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  • 1.
    Alriksson, Björn
    et al.
    Karlstad University, Sweden.
    Rose, S. H.
    University of Stellenbosch, South Africa.
    Van Zyl, W. H.
    University of Stellenbosch, South Africa.
    Sjöde, A.
    Karlstad University, Sweden.
    Nilvebrant, N. -O
    RISE., STFI-Packforsk. Karlstad University, Sweden.
    Jönsson, L. J.
    Karlstad University, Sweden; Umeå University, Sweden.
    Cellulase production from spent lignocellulose hydrolysates by recombinant aspergillus niger2009Ingår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 75, nr 8, s. 2366-2374Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A recombinant Aspergillus niger strain expressing the Hypocrea jecorina endoglucanase Cel7B was grown on spent hydrolysates (stillage) from sugarcane bagasse and spruce wood. The spent hydrolysates served as excellent growth media for the Cel7B-producing strain, A. niger D15[egI], which displayed higher endoglucanase activities in the spent hydrolysates than in standard medium with a comparable monosaccharide content (e.g., 2,100 nkat/ml in spent bagasse hydrolysate compared to 480 nkat/ml in standard glucose-based medium). In addition, A. niger D15[egI] was also able to consume or convert other lignocellulose-derived compounds, such as acetic acid, furan aldehydes, and phenolic compounds, which are recognized as inhibitors of yeast during ethanolic fermentation. The results indicate that enzymes can be produced from the stillage stream as a high-value coproduct in secondgeneration bioethanol plants in a way that also facilitates recirculation of process water.

  • 2.
    Benavente, Verónica
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi. Umeå university, Sweden.
    Pérez, Carla
    Umeå university, Sweden.
    Jansson, Stina
    Umeå university, Sweden.
    Co-hydrothermal carbonization of microalgae and digested sewage sludge: Assessing the impact of mixing ratios on the composition of primary and secondary char2024Ingår i: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 174, s. 429-438Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The role of microalgae cultivation in wastewater treatment and reclamation has been studied extensively, as has the potential utility of the resulting algal biomass. Most methods for processing such biomass generate solid residues that must be properly managed to comply with current sustainable resource utilization requirements. Hydrothermal carbonization (HTC) can be used to process both individual wet feedstocks and mixed feedstocks (i.e., co-HTC). Here, we investigate co-HTC using microalgae and digested sewage sludge as feedstocks. The objectives were to (i) study the material’s partitioning into solid and liquid products, and (ii) characterize the products’ physicochemical properties. Co-HTC experiments were conducted at 180–250°C using mixed microalgae/sewage sludge feedstocks with the proportion of sewage sludge ranging from 0 to 100 %. Analyses of the hydrochar composition and the formation and composition of secondary char revealed that the content of carbonized material in the product decreased as the proportion of sewage sludge in the feedstock increased under fixed carbonization conditions. The properties of the hydrochars and the partitioning of material between the liquid phase and the hydrochar correlated linearly with the proportion of microalgae in mixed feedstocks, indicating that adding sewage sludge to microalgae had weak or non-existent synergistic effects on co-HTC outcomes. However, the proportion of sewage sludge in the feedstock did affect the secondary char. For example, adding sewage sludge reduced the abundance of carboxylic acids and ketones as well as the concentrations of higher molecular weight cholesterols. Such changes may alter the viable applications of the hydrochar. 

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  • 3.
    Bergentall, Martina
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Malafronte, Loredana
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel. AstraZeneca, Sweden.
    As, Dorine
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel. Hedelab, Belgium.
    Calmet, Emeline
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel. Fleury Michon, France.
    Melin, Petter
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Reduction of malic acid in bilberry juice by Lactiplantibacillus plantarum-mediated malolactic fermentation2024Ingår i: European Food Research and Technology, ISSN 1438-2377, E-ISSN 1438-2385, Vol. 250, nr 3, s. 811-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bilberries (Vaccinium myrtillus) are the most common wild berries in Northern Europe. A substantial amount of the berries are picked with the objective to extract highly valued products such as anthocyanins. A smaller amount of the bilberries is used to make jams and drinks, and these are generally restricted to the domestic market. One reason is the sour taste, partly as a result of the high content of malic acid. By using certain strains of lactic acid bacteria with the ability to convert malic acid to lactic acid, the taste is predicted to be more pleasant. This process is called malolactic fermentation, and historically it has mostly been used in winemaking. After testing five different starter cultures, we identified that the strain, Lactiplantibacillus plantarum LP58, can rapidly convert malic acid to lactic acid without any loss of sugar or citric acid, which strongly indicates a successful malolactic acid fermentation. As it has been reported that other strains of L. plantarum can be used as biopreservative agents, the resulting product was also tested in terms of microbial safety after prolonged storage, and by means of metagenome sequencing. The obtained product was quite tolerant to microbial growth, but this observation was rather due to an initial heat treatment than the addition of lactobacilli. Potentially, starter cultures with documented biopreservative activity can be combined with L. plantarum LP58 to obtain a more stable product. Until then, the fermented bilberry juice must be processed and preserved like non-fermented bilberry products. © 2023, The Author(s).

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  • 4.
    Björkmalm, Johanna
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Energi och cirkulär ekonomi.
    Byrne, Eoin
    Lund University, Sweden.
    van Niel, Ed
    Lund University, Sweden.
    Willquist, Karin
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Energi och cirkulär ekonomi.
    A non-linear model of hydrogen production by Caldicellulosiruptor saccharolyticus for diauxic-like consumption of lignocellulosic sugar mixtures2018Ingår i: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 11, artikel-id 175Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background

    Caldicellulosiruptor saccharolyticus is an attractive hydrogen producer suitable for growth on various lignocellulosic substrates. The aim of this study was to quantify uptake of pentose and hexose monosaccharides in an industrial substrate and to present a kinetic growth model of C. saccharolyticus that includes sugar uptake on defined and industrial media. The model is based on Monod and Hill kinetics extended with gas-to-liquid mass transfer and a cybernetic approach to describe diauxic-like growth.

    Results

    Mathematical expressions were developed to describe hydrogen production by C. saccharolyticus consuming glucose, xylose, and arabinose. The model parameters were calibrated against batch fermentation data. The experimental data included four different cases: glucose, xylose, sugar mixture, and wheat straw hydrolysate (WSH) fermentations. The fermentations were performed without yeast extract. The substrate uptake rate of C. saccharolyticus on single sugar-defined media was higher on glucose compared to xylose. In contrast, in the defined sugar mixture and WSH, the pentoses were consumed faster than glucose. Subsequently, the cultures entered a lag phase when all pentoses were consumed after which glucose uptake rate increased. This phenomenon suggested a diauxic-like behavior as was deduced from the successive appearance of two peaks in the hydrogen and carbon dioxide productivity. The observation could be described with a modified diauxic model including a second enzyme system with a higher affinity for glucose being expressed when pentose saccharides are consumed. This behavior was more pronounced when WSH was used as substrate.

    Conclusions

    The previously observed co-consumption of glucose and pentoses with a preference for the latter was herein confirmed. However, once all pentoses were consumed, C. saccharolyticus most probably expressed another uptake system to account for the observed increased glucose uptake rate. This phenomenon could be quantitatively captured in a kinetic model of the entire diauxic-like growth process. Moreover, the observation indicates a regulation system that has fundamental research relevance, since pentose and glucose uptake in C. saccharolyticus has only been described with ABC transporters, whereas previously reported diauxic growth phenomena have been correlated mainly to PTS systems for sugar uptake.

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  • 5.
    Byrne, Eoin
    et al.
    Lund University, Sweden; Teagasc Food Research Centre, Ireland.
    Björkmalm, Johanna
    RISE Research Institutes of Sweden, Samhällsbyggnad, Energi och resurser. Lund University, Sweden.
    Bostick, James
    Lund University, Sweden; Coriolis Pharma Research GmbH, Germany.
    Sreenivas, Krishnan
    Lund University, Sweden.
    Willquist, Karin
    RISE Research Institutes of Sweden.
    van Niel, Ed
    Lund University, Sweden.
    Characterization and adaptation of Caldicellulosiruptor strains to higher sugar concentrations, targeting enhanced hydrogen production from lignocellulosic hydrolysates2021Ingår i: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 14, nr 1, artikel-id 210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The members of the genus Caldicellulosiruptor have the potential for future integration into a biorefinery system due to their capacity to generate hydrogen close to the theoretical limit of 4 mol H2/mol hexose, use a wide range of sugars and can grow on numerous lignocellulose hydrolysates. However, members of this genus are unable to survive in high sugar concentrations, limiting their ability to grow on more concentrated hydrolysates, thus impeding their industrial applicability. In this study five members of this genus, C.owensensis, C. kronotskyensis, C.bescii, C.acetigenus and C.kristjanssonii, were developed to tolerate higher sugar concentrations through an adaptive laboratory evolution (ALE) process. The developed mixed population C.owensensis CO80 was further studied and accompanied by the development of a kinetic model based on Monod kinetics to quantitatively compare it with the parental strain. Results: Mixed populations of Caldicellulosiruptor tolerant to higher glucose concentrations were obtained with C.owensensis adapted to grow up to 80 g/L glucose; other strains in particular C. kristjanssonii demonstrated a greater restriction to adaptation. The C.owensensis CO80 mixed population was further studied and demonstrated the ability to grow in glucose concentrations up to 80 g/L glucose, but with reduced volumetric hydrogen productivities (QH2) and incomplete sugar conversion at elevated glucose concentrations. In addition, the carbon yield decreased with elevated concentrations of glucose. The ability of the mixed population C.owensensis CO80 to grow in high glucose concentrations was further described with a kinetic growth model, which revealed that the critical sugar concentration of the cells increased fourfold when cultivated at higher concentrations. When co-cultured with the adapted C.saccharolyticus G5 mixed culture at a hydraulic retention time (HRT) of 20 h, C.owensensis constituted only 0.09–1.58% of the population in suspension. Conclusions: The adaptation of members of the Caldicellulosiruptor genus to higher sugar concentrations established that the ability to develop improved strains via ALE is species dependent, with C.owensensis adapted to grow on 80 g/L, whereas C.kristjanssonii could only be adapted to 30 g/L glucose. Although C.owensensis CO80 was adapted to a higher sugar concentration, this mixed population demonstrated reduced QH2 with elevated glucose concentrations. This would indicate that while ALE permits adaptation to elevated sugar concentrations, this approach does not result in improved fermentation performances at these higher sugar concentrations. Moreover, the observation that planktonic mixed culture of CO80 was outcompeted by an adapted C.saccharolyticus, when co-cultivated in continuous mode, indicates that the robustness of CO80 mixed culture should be improved for industrial application. © 2021, The Author(s).

  • 6.
    Chambi, Diego
    et al.
    Umeå University, Sweden; Universidad Mayor de San Andrés, Bolivia; Ministerio de Desarrollo Productivo y Economía Plural, Bolivia.
    Lundqvist, Jenny
    Umeå University, Sweden.
    Nygren, Erik
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Romero-Soto, Luis
    Universidad Mayor de San Andrés, Bolivia.
    Marin, Katherine
    Umeå University, Sweden; Universidad Mayor de San Andrés, Bolivia.
    Gorzsás, András
    Umeå University, Sweden.
    Hedenström, Mattias
    Umeå University, Sweden.
    Carlborg, Markus
    Umeå University, Sweden.
    Broström, Markus
    Umeå University, Sweden.
    Sundman, Ola
    Umeå University, Sweden.
    Carrasco, Cristhian
    Universidad Mayor de San Andrés, Bolivia.
    Jönsson, Leif J.
    Umeå University, Sweden.
    Martín, Carlos
    Umeå University, Sweden; Inland Norway University of Applied Sciences, Norway.
    Production of Exopolysaccharides by Cultivation of Halotolerant Bacillus atrophaeus BU4 in Glucose- and Xylose-Based Synthetic Media and in Hydrolysates of Quinoa Stalks2022Ingår i: Fermentation, E-ISSN 2311-5637, Vol. 8, nr 2, artikel-id 79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A halotolerant, exopolysaccharide-producing bacterium isolated from the Salar de Uyuni salt flat in Bolivia was identified as Bacillus atrophaeus using next-generation sequencing. Comparisons indicate that the genome most likely (p-value: 0.0024) belongs to a subspecies previously not represented in the database. The growth of the bacterial strain and its ability to produce exopolysaccharides (EPS) in synthetic media with glucose or xylose as carbon sources, and in hydrolysates of quinoa stalks, was investigated. The strain grew well in all synthetic media, but the growth in glucose was better than that in xylose. Sugar consumption was better when initial concentrations were low. The growth was good in enzymatically produced cellulosic hydrolysates but was inhibited in hemicellulosic hydrolysates produced using hydrothermal pretreatment. The EPS yields were up to 0.064 g/g on initial glucose and 0.047 g/g on initial xylose, and was higher in media with relatively low sugar concentrations. The EPS was isolated and purified by a sequential procedure including centrifugation, cold ethanol precipitation, trichloroacetic acid treatment, dialysis, and freeze-drying. Glucose and mannose were the main sugars identified in hydrolyzed EPS. The EPS was characterized by size-exclusion chromatography, Fourier-transform infrared (FTIR) spectroscopy, heteronuclear single-quantum coherence nuclear magnetic resonance (HSQC NMR) spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. No major differences were elucidated between EPS resulting from cultivations in glucose- or-xylose-based synthetic media, while some divergences with regard to molecular-weight averages and FTIR and HSQC NMR spectra were detected for EPS from hydrolysate-based media.

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  • 7.
    Chandolias, Konstantinos
    et al.
    RISE Research Institutes of Sweden, Samhällsbyggnad, Energi och resurser.
    Pawar, Sudhanshu
    Fortum Sverige AB, Sweden.
    Vu, H. D.
    University of Borås, Sweden.
    Wainaina, S.
    University of Borås, Sweden.
    Taherzadeh, M. J.
    University of Borås, Sweden.
    Bio‑hydrogen and VFA production from steel mill gases using pure and mixed bacterial cultures2023Ingår i: Bioresource Technology Reports, ISSN 2589-014X, Vol. 23, artikel-id 101544Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A major source of CO2 emissions is the flaring of steel mill gas. This work demonstrated the enrichment of carboxydotrophic bacteria for converting steel mill gas into volatile fatty acids and H2, via gas fermentation. Several combinations of pure and mixed anaerobic cultures were used as inoculum in 0.5-L reactors, operated at 30 and 60 °C. The process was then scaled up in a 4-L membrane bioreactor, operated for 20 days, at 48 °C. The results showed that the enriched microbiomes can oxidize CO completely to produce H2/H+ which is subsequently used to fix the CO2. At 30 °C, a mixture of acetate, isobutyrate and propionate was obtained while H2 and acetate were the main products at 60 °C. The highest CO conversion and H2 production rate observed in the membrane bioreactor were 29 and 28 mL/LR/h, respectively. The taxonomic diversity of the bacterial community increased and the dominant species was Pseudomonas.

  • 8.
    Cheng, G.
    et al.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Gabler, Florian
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi. SLU Swedish University of Agricultural Sciences, Sweden.
    Pizzul, Leticia
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Olsson, Henrik
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi.
    Nordberg, Åke
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi. SLU Swedish University of Agricultural Sciences, Sweden.
    Schnürer, A.
    SLU Swedish University of Agricultural Sciences, Sweden.
    Microbial community development during syngas methanation in a trickle bed reactor with various nutrient sources2022Ingår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 106, s. 5317-5333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Microbial community development within an anaerobic trickle bed reactor (TBR) during methanation of syngas (56% H2, 30% CO, 14% CO2) was investigated using three different nutrient media: defined nutrient medium (241 days), diluted digestate from a thermophilic co-digestion plant operating with food waste (200 days) and reject water from dewatered digested sewage sludge at a wastewater treatment plant (220 days). Different TBR operating periods showed slightly different performance that was not clearly linked to the nutrient medium, as all proved suitable for the methanation process. During operation, maximum syngas load was 5.33 L per L packed bed volume (pbv) & day and methane (CH4) production was 1.26 L CH4/Lpbv/d. Microbial community analysis with Illumina Miseq targeting 16S rDNA revealed high relative abundance (20–40%) of several potential syngas and acetate consumers within the genera Sporomusa, Spirochaetaceae, Rikenellaceae and Acetobacterium during the process. These were the dominant taxa except in a period with high flow rate of digestate from the food waste plant. The dominant methanogen in all periods was a member of the genus Methanobacterium, while Methanosarcina was also observed in the carrier community. As in reactor effluent, the dominant bacterial genus in the carrier was Sporomusa. These results show that syngas methanation in TBR can proceed well with different nutrient sources, including undefined medium of different origins. Moreover, the dominant syngas community remained the same over time even when non-sterilised digestates were used as nutrient medium. Key points: •Independent of nutrient source, syngas methanation above 1 L/Lpbv/D was achieved. •Methanobacterium and Sporomusa were dominant genera throughout the process. •Acetate conversion proceeded via both methanogenesis and syntrophic acetate oxidation. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s).

  • 9. Ciranna, Alessandro
    et al.
    Pawar, Sudhanshu
    Santala, Ville
    Karp, Matti
    van Niel, Ed W. J.
    Assessment of metabolic flux distribution in the thermophilic hydrogen producer Caloramator celer as affected by external pH and hydrogen partial pressure.2014Ingår i: Microbial Cell Factories, ISSN 1475-2859, E-ISSN 1475-2859, Vol. 13, nr 1, artikel-id 48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Caloramator celer is a strict anaerobic, alkalitolerant, thermophilic bacterium capable of converting glucose to hydrogen (H2), carbon dioxide, acetate, ethanol and formate by a mixed acid fermentation. Depending on the growth conditions C. celer can produce H2 at high yields. For a biotechnological exploitation of this bacterium for H2 production it is crucial to understand the factors that regulate carbon and electron fluxes and therefore the final distribution of metabolites to channel the metabolic flux towards the desired product.

    RESULTS: Combining experimental results from batch fermentations with genome analysis, reconstruction of central carbon metabolism and metabolic flux analysis (MFA), this study shed light on glucose catabolism of the thermophilic alkalitolerant bacterium C. celer. Two innate factors pertaining to culture conditions have been identified to significantly affect the metabolic flux distribution: culture pH and partial pressures of H2 (PH2). Overall, at alkaline to neutral pH the rate of biomass synthesis was maximized, whereas at acidic pH the lower growth rate and the less efficient biomass formation are accompanied with more efficient energy recovery from the substrate indicating high cell maintenance possibly to sustain intracellular pH homeostasis. Higher H2 yields were associated with fermentation at acidic pH as a consequence of the lower synthesis of other reduced by-products such as formate and ethanol. In contrast, PH2 did not affect the growth of C. celer on glucose. At high PH2 the cellular redox state was balanced by rerouting the flow of carbon and electrons to ethanol and formate production allowing unaltered glycolytic flux and growth rate, but resulting in a decreased H2 synthesis.

    CONCLUSION: C. celer possesses a flexible fermentative metabolism that allows redistribution of fluxes at key metabolic nodes to simultaneously control redox state and efficiently harvest energy from substrate even under unfavorable conditions (i.e. low pH and high PH2). With the H2 production in mind, acidic pH and low PH2 should be preferred for a high yield-oriented process, while a high productivity-oriented process can be achieved at alkaline pH and high PH2.

  • 10.
    de Knegt, Leonardo V.
    et al.
    DTU Technical University of Denmark, Denmark.
    Pires, Sara M.
    DTU Technical University of Denmark, Denmark.
    Löfström, Charlotta
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience, Microbiology. DTU Technical University of Denmark, Denmark.
    Sörensen, Gitte
    DTU Technical University of Denmark, Denmark.
    Pedersen, Karl
    DTU Technical University of Denmark, Denmark.
    Torpdahl, Mia
    Statens Serum Institut, Denmark.
    Nielsen, Eva M.
    Statens Serum Institut, Denmark.
    Hald, Tine
    DTU Technical University of Denmark, Denmark.
    Application of Molecular Typing Results in Source Attribution Models: The Case of Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) of Salmonella Isolates Obtained from Integrated Surveillance in Denmark2016Ingår i: Risk Analysis, ISSN 0272-4332, E-ISSN 1539-6924, Vol. 36, nr 3, s. 571-588Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Salmonella is an important cause of bacterial foodborne infections in Denmark. To identify the main animal-food sources of human salmonellosis, risk managers have relied on a routine application of a microbial subtyping-based source attribution model since 1995. In 2013, multiple locus variable number tandem repeat analysis (MLVA) substituted phage typing as the subtyping method for surveillance of S. Enteritidis and S. Typhimurium isolated from animals, food, and humans in Denmark. The purpose of this study was to develop a modeling approach applying a combination of serovars, MLVA types, and antibiotic resistance profiles for the Salmonella source attribution, and assess the utility of the results for the food safety decisionmakers. Full and simplified MLVA schemes from surveillance data were tested, and model fit and consistency of results were assessed using statistical measures. We conclude that loci schemes STTR5/STTR10/STTR3 for S. Typhimurium and SE9/SE5/SE2/SE1/SE3 for S. Enteritidis can be used in microbial subtyping-based source attribution models. Based on the results, we discuss that an adjustment of the discriminatory level of the subtyping method applied often will be required to fit the purpose of the study and the available data. The issues discussed are also considered highly relevant when applying, e.g., extended multi-locus sequence typing or next-generation sequencing techniques.

  • 11.
    Diler, Erwan
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Korrosion.
    Leblanc, Vanessa
    Corrodys, France.
    Gueuné, Herve
    Corrodys, France.
    Maillot, Valerie
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Linard, Yannick
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Charrier, Gaelle
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Crusset, Didier
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Potential influence of microorganisms on the corrosion of carbon steel in the French high-level long-lived radioactive waste disposal context at 80°C2023Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 74, nr 11-12, s. 1795-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high-level radioactive waste disposal. The exposures were carried out at 80°C in different repository relevant conditions, including the presence of different cement-grout mixtures as filling material. Biotic conditions with nutrient and nonsterile conditions with indigenous microbes added from Callovo Oxfordian clayey rock and without nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at Andra's Underground Research Laboratory and microorganisms from microbial culture collection centers. Corrosion kinetics were determined using traditional coupons and completed with real-time corrosion sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next-generation sequencing. The obtained results show no significant MIC and a reduced risk with the use of more alkaline filling material. © 2023 The Authors. 

  • 12.
    Diler, Erwan
    et al.
    RISE Research Institutes of Sweden, Material och produktion, Korrosion.
    Leblanc, Vanessa
    Corrodys, France.
    Gueuné, Herve
    Corrodys, France.
    Maillot, Valerie
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Linard, Yannick
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Charrier, Gaelle
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Crusset, Didier
    ANDRA Agence nationale pour la gestion des déchets radioactifs, France.
    Potential influence of microorganisms on the corrosion of the carbon steel in the French high-level long-lived nuclear waste disposal context at 50°C2023Ingår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176, Vol. 74, s. 1177-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, short-term experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high-level radioactive waste disposal CIGEO (Centre Industriel de Stockage Géologique). The exposures were carried out in different representative media, including the presence of different cement-grout mixtures as filling material. Nonsterile and biotic conditions with nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at ANDRA's Underground Research Laboratory and microorganisms from the library. Corrosion kinetics were determined using both traditional coupons and completed with real-time electrical resistance sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next-generation sequencing. The obtained results show no significant MIC, but a reduced risk was observed using more alkaline filling materials. © 2023 The Authors.

  • 13.
    Fachmann, M S R
    et al.
    DTU Technical University of Denmark, Denmark.
    Löfström, Charlotta
    RISE - Research Institutes of Sweden, Biovetenskap och material, Jordbruk och livsmedel. DTU Technical University of Denmark, Denmark.
    Hoorfar, J
    DTU Technical University of Denmark, Denmark.
    Hansen, F
    DMRI Danish Technological Institute, Denmark.
    Christensen, J
    DTU Technical University of Denmark, Denmark.
    Mansdal, S
    DTI Danish Technological Institute, Denmark.
    Josefsen, M H
    DTU Technical University of Denmark, Denmark.
    Detection of Salmonella in meat in less than 5 hours by a low-cost and non-complex sample preparation method.2017Ingår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 83, nr 5, artikel-id e03151-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Salmonella is recognised as one of the most important foodborne bacteria, and has a wide health and socioeconomical impact worldwide. Fresh pork meat is one of the main sources of Salmonella and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in few cases < 12 h, thus requiring at least two working shifts. Here, we report a rapid (< 5 h) and high throughput method, for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water, and a real-time PCR compatible sample preparation method, based on filtration, centrifugation, and enzymatic digestion, followed by fast cycling real-time PCR detection. The method was validated in an un-paired, comparative study against the Nordic Committee on Food Analysis (NMKL) reference culture method 187. Pork meat samples (n=140) were either artificially contaminated with Salmonella at levels: 0, 1-10 and 10-100 CFU/25 g, or naturally contaminated. Cohen's Kappa for degree of agreement between the rapid method and the reference was 0.64 and the relative accuracy, sensitivity and specificity for the rapid method were 81.4, 95.1 and 97.9 %, respectively. The limit of detection (LOD50) was 8.8 CFU/25 g for the rapid method and 7.7 CFU/25 g for the reference method. Implementation of this method will enable faster release of Salmonella low risk meat, providing savings for meat producers, and help contribute to improved food safety.

    IMPORTANCE: While the cost of analysis and hands-on time of the presented rapid method were comparable to reference culture methods, the fast product release by this method can provide the meat industry with a competitive advantage. Not only will the abattoirs save costs for work hours and cold storage; consumers as well as retailers will also benefit from fresher meat with a longer shelf life. Furthermore, the presented sample preparation might be adjusted for application in detection of other pathogenic bacteria in different sample types.

  • 14.
    Garrido Banuelos, Gonzalo
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Miljkovic, Ana
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Morange, Clement
    RISE Research Institutes of Sweden.
    Mihnea, Mihaela
    Örebro University, Sweden.
    Lopez-Sanchez, Patricia
    Chalmers University of Technology, Sweden.
    Assessing the volatile composition of seaweed (Laminaria digitata) suspensions as function of thermal and mechanical treatments2022Ingår i: Lebensmittel-Wissenschaft + Technologie, ISSN 0023-6438, E-ISSN 1096-1127, Vol. 162, artikel-id 113483Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Macroalgae are a rich source of dietary fibre, protein, lipids and bioactives. However, more research is needed to understand how processing methods impact macroalgae techno-functional properties. In this work, aqueous suspensions of the fibre-rich brown algae Laminaria digitata were prepared by conventional food processing methods. The impact of sequence of processing steps (thermal and mechanical treatments), and heating time (15, 30 and 45 min), on volatile aroma composition were investigated. Changes in volatile composition were monitored with headspace GC-FID/MS analysis. Our results showed that both parameters impacted the volatiles profile of the suspensions. From an overall volatile perspective, short heating times (90 °C for 15 min) led to similar profiles, independently of the sequence of thermal and mechanical treatments. However, longer heating times induced a larger release of several aldehydes, specific for each processing method. Our results bring new insights on the volatile composition of suspensions of Laminaria digitata, which are related to flavour properties, and aid design of food products containing seaweed. © 2022 The Authors

  • 15.
    Hellmér, Maria
    et al.
    DTU Technical University of Denmark, Denmark.
    Hjelmsø, Mathis Hjort
    DTU Technical University of Denmark, Denmark.
    Fernandez-Cassi, Xavier
    University of Barcelona, Spain.
    Timoneda, Natalia
    University of Barcelona, Spain.
    Lukjancenko, Oksana
    DTU Technical University of Denmark, Denmark.
    Seidel, Michael
    Technical University of Munich, Germany.
    Aarestrup, Frank Møller
    DTU Technical University of Denmark, Denmark.
    Löfström, Charlotta
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience. DTU Technical University of Denmark, Denmark.
    Girones, Rosina
    University of Barcelona, Spain.
    Schultz, Anna Charlotte
    DTU Technical University of Denmark, Denmark.
    Evaluation of methods for the concentration and extraction of viruses from sewage water in the context of metagenomic sequencing2016Ingår i: The Danish Microbiological Society Annual Congress 2016: Programme & Abstracts, Copenhagen, 2016, s. 76-76, artikel-id P61Konferensbidrag (Övrigt vetenskapligt)
  • 16.
    Hintzmann, Ann-Sofie
    et al.
    DTU Technical University of Denmark, Denmark.
    Sørensen, Gitte
    DTU Technical University of Denmark, Denmark.
    Löfström, Charlotta
    RISE - Research Institutes of Sweden, Biovetenskap och material, Jordbruk och livsmedel. DTU Technical University of Denmark, Denmark.
    Baggesen, Dorte Lau
    DTU Technical University of Denmark, Denmark.
    Whole genome sequencing data confirm transmission of Salmonella enterica serovar Typhimurium phage type DT41 in the Danish poultry production chain2017Konferensbidrag (Övrigt vetenskapligt)
  • 17.
    Hintzmann, Ann-Sofie
    et al.
    DTU Technical University of Denmark, Denmark.
    Sørensen, Gitte
    DTU Technical University of Denmark, Denmark.
    Löfström, Charlotta
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience. DTU Technical University of Denmark, Denmark.
    Baggesen, Dorte Lau
    DTU Technical University of Denmark, Denmark.
    Whole genome sequencing data confirm transmission of Salmonella enterica serovar Typhimurium phage type DT41 in the Danish poultry production chain2016Ingår i: Technical meeting on the Impact of Whole Genome Sequencing on food safety management: Poster abstracts, Rome, Italy: Food and Agriculture Organization of the United Nations (FAO), 2016, s. 12-12, artikel-id 11Konferensbidrag (Övrigt vetenskapligt)
  • 18.
    Hjelmsø, Mathis Hjort
    et al.
    DTU Technical University of Denmark, Denmark.
    Hellmér, Maria
    DTU Technical University of Denmark, Denmark.
    Fernandez-Cassi, Xavier
    University of Barcelona, Spain.
    Timoneda, Natàlia
    University of Barcelona, Spain.
    Lukjancenko, Oksana
    DTU Technical University of Denmark, Denmark.
    Seidel, Michael
    Technical University of Munich, Germany.
    Elsässer, Dennis
    Technical University of Munich, Germany.
    Aarestrup, Frank M
    DTU Technical University of Denmark, Denmark.
    Löfström, Charlotta
    RISE - Research Institutes of Sweden, Biovetenskap och material, Jordbruk och livsmedel. DTU Technical University of Denmark, Denmark.
    Bofill-Mas, Sílvia
    University of Barcelona, Spain.
    Abril, Josep F
    University of Barcelona,Spain.
    Girones, Rosina
    University of Barcelona, Spain.
    Schultz, Anna Charlotte
    DTU Technical University of Denmark, Denmark.
    Evaluation of Methods for the Concentration and Extraction of Viruses from Sewage in the Context of Metagenomic Sequencing.2017Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 12, nr 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Viral sewage metagenomics is a novel field of study used for surveillance, epidemiological studies, and evaluation of waste water treatment efficiency. In raw sewage human waste is mixed with household, industrial and drainage water, and virus particles are, therefore, only found in low concentrations. This necessitates a step of sample concentration to allow for sensitive virus detection. Additionally, viruses harbor a large diversity of both surface and genome structures, which makes universal viral genomic extraction difficult. Current studies have tackled these challenges in many different ways employing a wide range of viral concentration and extraction procedures. However, there is limited knowledge of the efficacy and inherent biases associated with these methods in respect to viral sewage metagenomics, hampering the development of this field. By the use of next generation sequencing this study aimed to evaluate the efficiency of four commonly applied viral concentrations techniques (precipitation with polyethylene glycol, organic flocculation with skim milk, monolithic adsorption filtration and glass wool filtration) and extraction methods (Nucleospin RNA XS, QIAamp Viral RNA Mini Kit, NucliSENS® miniMAG®, or PowerViral® Environmental RNA/DNA Isolation Kit) to determine the viriome in a sewage sample. We found a significant influence of concentration and extraction protocols on the detected viriome. The viral richness was largest in samples extracted with QIAamp Viral RNA Mini Kit or PowerViral® Environmental RNA/DNA Isolation Kit. Highest viral specificity were found in samples concentrated by precipitation with polyethylene glycol or extracted with Nucleospin RNA XS. Detection of viral pathogens depended on the method used. These results contribute to the understanding of method associated biases, within the field of viral sewage metagenomics, making evaluation of the current literature easier and helping with the design of future studies.

  • 19.
    Hutinel, Marion
    et al.
    University of Gothenburg, Sweden.
    Fick, Jerker
    Umeå University, Sweden.
    Larsson, D G Joakim
    University of Gothenburg, Sweden.
    Flach, Carl-Fredrik
    University of Gothenburg, Sweden.
    Investigating the effects of municipal and hospital wastewaters on horizontal gene transfer.2021Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 276, s. 116733-, artikel-id 116733Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Horizontal gene transfer (HGT) plays an important role in the dissemination of antibiotic resistance genes. In sewer systems, human-associated and environmental bacteria are mixed together and exposed to many substances known to increase HGT, including various antibacterial compounds. In wastewaters, those substances are most often detected below concentrations known to induce HGT individually. Still, it is possible that such wastewaters induce HGT, for example via mixture effects. Here, a panel of antibiotics, biocides and other pharmaceuticals was measured in filter-sterilized municipal and hospital wastewater samples from Gothenburg, Sweden. The effects on HGT of the chemical mixtures in these samples were investigated by exposing a complex bacterial donor community together with a GFP-tagged E. coli recipient strain. Recipients that captured sulfonamide resistance-conferring mobile genetic elements (MGEs) from the bacterial community were enumerated and characterized by replicon typing, antibiotic susceptibility testing and long read sequencing. While exposure to municipal wastewater did not result in any detectable change in HGT rates, exposure to hospital wastewater was associated with an increase in the proportion of recipients that acquired sulfonamide resistance but also a drastic decrease in the total number of recipients. Although, concentrations were generally higher in hospital than municipal wastewater, none of the measured substances could individually explain the observed effects of hospital wastewater. The great majority of the MGEs captured were IncN plasmids, and resistance to several antibiotics was co-transferred in most cases. Taken together, the data show no evidence that chemicals present in the studied municipal wastewater induce HGT. Still, the increased relative abundance of transconjugants after exposure to hospital wastewater could have implications for the risks of both emergence and transmission of resistant bacteria.

  • 20.
    Hutinel, Marion
    et al.
    University of Gothenburg,Sweden.
    Larsson, D G Joakim
    University of Gothenburg,Sweden.
    Flach, Carl-Fredrik
    University of Gothenburg,Sweden.
    Antibiotic resistance genes of emerging concern in municipal and hospital wastewater from a major Swedish city.2022Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 812, artikel-id 151433Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The spread of antibiotic resistance among bacterial pathogens is to a large extent mediated by mobile antibiotic resistance genes (ARGs). The prevalence and geographic distribution of several newly discovered ARGs, as well as some clinically important ARGs conferring resistance to last resort antibiotics, are largely unknown. Targeted analysis of wastewater samples could allow estimations of carriage in the population connected to the sewers as well as release to the environment. Here we quantified ARGs conferring resistance to linezolid (optrA and cfr(A)) and colistin (mcr-1, -2, -3, -4 and -5) and the recently discovered gar (aminoglycoside ARG) and sul4 (sulphonamide ARG) in raw hospital and municipal wastewater as well as treated municipal wastewater during five years in a low antibiotic resistance prevalence setting (Gothenburg, Sweden). Additionally, variations in bacterial composition of the wastewaters characterized by 16S rRNA sequencing were related to the variations of the ARGs in an attempt to reveal if the presence of known or suspected bacterial host taxa could explain the presence of the ARGs in wastewater. The mcr-1, mcr-3, mcr-4, mcr-5, sul4 and gar genes were detected regularly in all types of wastewater samples while optrA and cfr(A) were detected only in hospital wastewater. The most abundant genes were mcr-3 and mcr-5, especially in municipal wastewater. The detection of optrA was restricted to a peak during one year. Most of the ARGs correlated with taxa previously described as bacterial hosts and associated with humans. Although some of the tentative hosts may include bacteria also thriving in wastewater environments, detection of the ARGs in the wastewaters could reflect their presence in the gut flora of the contributing populations. If so, they could already today or in the near future hinder treatment of bacterial infections in a setting where they currently are rarely targeted/detected during clinical surveillance.

  • 21.
    Johansson, Pernilla
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Samhällsbyggnad, Byggteknik.
    Mjörnell, Kristina
    RISE - Research Institutes of Sweden (2017-2019).
    Arfvidsson, J.
    Lund University, Sweden.
    Examples of characteristics of wood that affect mould growth: a meta-analysis2017Ingår i: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 75, nr 4, s. 603-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Building materials differ in their susceptibility to mould growth. Wood is a material often considered to have a low mould resistance. However, wood is not a homogenous material and different characteristics of the material are expected to have an impact on mould growth. In this paper, it was shown that wood species (pine or spruce), sawing pattern (centre-board or side-board) and surface structure (planed or sawn) affected mould growth. In addition, it was indicated that the susceptibility cannot be described by one single parameter, but also depends on other parameters. It is therefore difficult to estimate the susceptibility of wood in general. These conclusions were drawn from a meta-analysis, using data from five separate, previously performed laboratory studies conducted at 90% relative humidity and 22 °C, and from a laboratory study performed at 95% RH and 22 °C. © 2016 Springer-Verlag Berlin Heidelberg

  • 22.
    Kraupner, Nadine
    et al.
    University of Gothenburg, Sweden.
    Ebmeyer, Stefan
    University of Gothenburg, Sweden.
    Hutinel, Marion
    University of Gothenburg, Sweden.
    Fick, Jerker
    Umeå University, Sweden.
    Flach, Carl-Fredrik
    University of Gothenburg, Sweden.
    Larsson, D G Joakim
    Selective concentrations for trimethoprim resistance in aquatic environments.2020Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 144, artikel-id 106083Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Antibiotic resistance presents a serious and still growing threat to human health. Environmental exposure levels required to select for resistance are unknown for most antibiotics. Here, we evaluated different experimental approaches and ways to interpret effect measures, in order to identify what concentration of trimethoprim that are likely to select for resistance in aquatic environments. When grown in complex biofilms, selection for resistant E. coli increased at 100 µg/L, whereas there was only a non-significant trend with regards to changes in taxonomic composition within the tested range (0-100 µg/L). Planktonic co-culturing of 149 different E. coli strains isolated from sewage again confirmed selection at 100 µg/L. Finally, pairwise competition experiments were performed with engineered E. coli strains carrying different trimethoprim resistance genes (dfr) and their sensitive counterparts. While strains with introduced resistance genes grew slower than the sensitive ones at 0 and 10 µg/L, a significant reduction in cost was found already at 10 µg/L. Defining lowest effect concentrations by comparing proportion of resistant strains to sensitive ones at the same time point, rather than to their initial ratios, will reflect the advantage a resistance factor can bring, while ignoring exposure-independent fitness costs. As costs are likely to be highly dependent on the specific environmental and genetic contexts, the former approach might be more suitable as a basis for defining exposure limits with the intention to prevent selection for resistance. Based on the present and other studies, we propose that 1 µg/L would be a reasonably protective exposure limit for trimethoprim in aquatic environments.

  • 23.
    Löfström, Charlotta
    RISE - Research Institutes of Sweden, Biovetenskap och material, Jordbruk och livsmedel.
    Pre-PCR processing strategies for rapid detection of Listeria monocytogenes in food and environmental samples2017Konferensbidrag (Övrigt vetenskapligt)
  • 24.
    Mateva, Gergana
    et al.
    National Diagnostic Research Veterinary Institute, Bulgaria.
    Pedersen, Karl
    DTU Technical University of Denmark, Denmark.
    Sørensen, Gitte
    DTU Technical University of Denmark, Denmark.
    Asseva, Galina
    National Center of Infectious and Parasitic Diseases, Bulgaria.
    Daskalov, Hristo
    National Diagnostic Research Veterinary Institute, Bulgaria.
    Petrov, Petar
    National Center of Infectious and Parasitic Diseases, Bulgaria.
    Kantardjiev, Todor
    National Center of Infectious and Parasitic Diseases, Bulgaria.
    Alexandar, Irina
    Bulgarian Academy of Sciences, Bulgaria.
    Löfström, Charlotta
    RISE - Research Institutes of Sweden (2017-2019), Biovetenskap och material, Jordbruk och livsmedel. DTU Technical University of Denmark, Denmark.
    Use of multiple-locusvariable-numberof tandem repeatsanalysis (MLVA) to investigate genetic diversity of Salmonellaenterica subsp. enterica serovar Typhimurium isolates fromhuman, food, and veterinary sources2018Ingår i: MicrobiologyOpen, E-ISSN 2045-8827, Vol. 7, nr 1, artikel-id e00528Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Salmonella enterica subspecies enterica serovar Typhimurium is the most common zoonotic pathogen in Bulgaria. To allow efficient outbreak investigations and surveillance in the food chain, accurate and discriminatory methods for typing are needed. This study evaluated the use of multiple-locus variable-number of tandem repeats analysis (MLVA) and compared results with antimicrobial resistance (AMR) determinations for 100 S. Typhimurium strains isolated in Bulgaria during 2008–2012 (50 veterinary/ food and 50 human isolates). Results showed that isolates were divided into 80 and 34 groups using MLVA and AMR, respectively. Simpson’s index of diversity was determined to 0.994 ± 0.003 and 0.945 ± 0.012. The most frequently encountered MLVA profiles were 3-11-9-NA-211 (n = 5); 3-12-9-NA-211 (n = 3); 3-12-11-21-311 (n = 3); 3-17-10-NA-311 (n = 3); 2-20-9-7-212 (n = 3); and 2-23-NA-NA-111 (n = 3). No clustering of isolates related to susceptibility/resistance to antimicrobials, source of isolation, or year of isolation was observed. Some MLVA types were found in both human and veterinary/food isolates, indicating a possible route of transmission. A majority (83%) of the isolates were found to be resistant against at least one antimicrobial and 44% against ≥4 antimicrobials. Further studies are needed to verify MLVA usefulness over a longer period of time and with more isolates, including outbreak strains.

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  • 25.
    Mukherjee, Vaskar
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Bioraffinaderi och energi. Chalmers University of Technology, Sweden.
    Lenitz, Ibai
    Chalmers University of Technology, Sweden.
    Lind, Ulrika
    University of Gothenburg, Sweden.
    Blomberg, Anders
    University of Gothenburg, Sweden.
    Nygård, Yvonne
    Chalmers University of Technology, Sweden.
    CRISPRi screen highlights chromatin regulation to be involved in formic acid tolerance in Saccharomyces cerevisiae2023Ingår i: Engineering Microbiology, ISSN 2667-3703, Vol. 3, nr 2, artikel-id 100076Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formic acid is one of the main weak acids in lignocellulosic hydrolysates that is known to be inhibitory to yeast growth even at low concentrations. In this study, we employed a CRISPR interference (CRISPRi) strain library comprising >9000 strains encompassing >98% of all essential and respiratory growth-essential genes, to study formic acid tolerance in Saccharomyces cerevisiae. To provide quantitative growth estimates on formic acid tolerance, the strains were screened individually on solid medium supplemented with 140 mM formic acid using the Scan-o-Matic platform. Selected resistant and sensitive strains were characterized in liquid medium supplemented with formic acid and in synthetic hydrolysate medium containing a combination of inhibitors. Strains with gRNAs targeting genes associated with chromatin remodeling were significantly enriched for strains showing formic acid tolerance. In line with earlier findings on acetic acid tolerance, we found genes encoding proteins involved in intracellular vesicle transport enriched among formic acid sensitive strains. The growth of the strains in synthetic hydrolysate medium followed the same trend as when screened in medium supplemented with formic acid. Strains sensitive to formic acid had decreased growth in the synthetic hydrolysate and all strains that had improved growth in the presence of formic acid also grew better in the hydrolysate medium. Systematic analysis of CRISPRi strains allowed identification of genes involved in tolerance mechanisms and provided novel engineering targets for bioengineering strains with increased resistance to inhibitors in lignocellulosic hydrolysates. © 2023 The Author(s)

  • 26. Mölelr, Hanne
    et al.
    Hagtved, Therese
    Lödrup, Nina
    Kirk Andersen, Jens
    Lundquist Madsen, Pernille
    Werge, Mads
    Are, Ane Kristine
    Reinikainen, Anu
    Rosengren, Åsa
    Kjellen, Jimmy
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Food and Bioscience, Microbiology.
    Stenmarck, Åsa
    Youhanan, Lena
    Food waste and date labelling - Issues affecting the durability2016Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The purpose of the project has been to identify how date labelling legislation on food is practised in Denmark, Finland, Norway and Sweden and how the durability can be affected in the food supply chain. The project recommends enhanced guidance for manufacturers, retailers and consumers.

  • 27.
    Nygren, Erik
    et al.
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Gonzales Strömberg, Lucia
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Logenius, Jenny
    Essity Hygiene and Health AB, Sweden.
    Husmark, Ulrika
    Essity Hygiene and Health AB, Sweden.
    Löfström, Charlotta
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Bergström, Birgitta
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Jordbruk och livsmedel.
    Potential sources of contamination on textiles and hard surfaces identified as high-touch sites near the patient environment2023Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 18, artikel-id e0287855Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hospital environment represents an important mediator for the transmission of healthcare-associated infections through direct and indirect hand contact with hard surfaces and textiles. In this study, bacteria on high-touch sites, including textiles and hard surfaces in two care wards in Sweden, were identified using microbiological culture methods and 16S rDNA sequencing. During a cross-sectional study, 176 high-touch hard surfaces and textiles were identified and further analysed using microbiological culture for quantification of total aerobic bacteria, Staphylococcus aureus, Clostridium difficile and Enterobacteriacae. The bacterial population structures were further analysed in 26 samples using 16S rDNA sequencing. The study showed a higher frequency of unique direct hand-textile contacts (36 per hour), compared to hard surfaces (2.2 per hour). Hard surfaces met the recommended standard of ≤ 5 CFU/cm2 for aerobic bacteria and ≤ 1 CFU/cm2 for S. aureus (53% and 35%, respectively) to a higher extent compared to textiles (19% and 30%, respectively) (P = 0.0488). The number of bacterial genera was higher on textiles than on the hard surfaces. Staphylococcus (30.4%) and Corynebacterium (10.9%) were the most representative genera for textiles and Streptococcus (13.3%) for hard surfaces. The fact that a big percentage of the textiles did not fulfil the criteria for cleanliness, combined with the higher bacterial diversity, compared to hard surfaces, are indicators that textiles were bacterial reservoirs and potential risk vectors for bacterial transmission. However, since most of the bacteria found in the study belonged to the normal flora, it was not possible to draw conclusions of textiles and hard surfaces as sources of healthcare associated infections. 2023 Nygren et al.

  • 28.
    Pawar, Sudhanshu
    et al.
    Lund University, Sweden.
    van Niel, E. W. J.
    Lund University, Sweden.
    Evaluation of assimilatory sulphur metabolism in Caldicellulosiruptor saccharolyticus2014Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976Artikel i tidskrift (Refereegranskat)
  • 29.
    Peciulyte, Ausra
    et al.
    Chalmers University of Technology, Sweden.
    Anasontzis, George E.
    Chalmers University of Technology, Sweden.
    Karlström, Katarina
    RISE., Innventia.
    Larsson, Per Tomas
    RISE., Innventia. KTH Royal Institute of Technology, Sweden.
    Olsson, Lisbeth
    RISE., Innventia. Chalmers University of Technology, Sweden.
    Morphology and enzyme production of Trichoderma reesei Rut C-30 are affected by the physical and structural characteristics of cellulosic substrates2014Ingår i: Fungal Genetics and Biology, ISSN 1087-1845, E-ISSN 1096-0937, Vol. 72, s. 64-72Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The industrial production of cellulolytic enzymes is dominated by the filamentous fungus Trichoderma reesei (anamorph of Hypocrea jecorina). In order to develop optimal enzymatic cocktail, it is of importance to understand the natural regulation of the enzyme profile as response to the growth substrate. The influence of the complexity of cellulose on enzyme production by the microorganisms is not understood. In the present study we attempted to understand how different physical and structural properties of cellulose-rich substrates affected the levels and profiles of extracellular enzymes produced by T. reesei. Enzyme production by T. reesei Rut C-30 was studied in submerged cultures on five different cellulose-rich substrates, namely, commercial cellulose Avicel® and industrial-like cellulosic pulp substrates which consist mainly of cellulose, but also contain residual hemicellulose and lignin. In order to evaluate the hydrolysis of the substrates by the fungal enzymes, the spatial polymer distributions were characterised by cross-polarisation magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C-NMR) in combination with spectral fitting. Proteins in culture supernatants at early and late stages of enzyme production were labeled by Tandem Mass Tags (TMT) and protein profiles were analysed by liquid chromatography-tandem mass spectrometry. The data have been deposited to the ProteomeXchange with identifier PXD001304. In total 124 proteins were identified and quantified in the culture supernatants, including cellulases, hemicellulases, other glycoside hydrolases, lignin-degrading enzymes, auxiliary activity 9 (AA9) family (formerly GH61), supporting activities of proteins and enzymes acting on cellulose, proteases, intracellular proteins and several hypothetical proteins. Surprisingly, substantial differences in the enzyme profiles were found even though there were minor differences in the chemical composition between the cellulose-rich substrates.

  • 30.
    Pedersen, Emma
    et al.
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Fant, Kristina
    RISE - Research Institutes of Sweden, Biovetenskap och material, Kemi och material.
    Guidance Document on Good In Vitro Method Practices (GIVIMP): Series on Testing and Assessment No. 2862018Övrigt (Övrigt vetenskapligt)
  • 31.
    Salva Serra, Francisco
    et al.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital,, Sweden; University of the Balearic Islands, Spain.
    Jaén-Luchoro, Daniel
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Marathe, Nachiket P.
    IMR Institute of Marine Research, Norway.
    Adlerberth, Ingegerd
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Moore, Edward R. B.
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden.
    Karlsson, Roger
    University of Gothenburg, Sweden; Sahlgrenska University Hospital, Sweden; Nanixis Consulting, Sweden.
    Responses of carbapenemase-producing and non-producing carbapenem-resistant Pseudomonas aeruginosa strains to meropenem revealed by quantitative tandem mass spectrometry proteomics2023Ingår i: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pseudomonas aeruginosa is an opportunistic pathogen with increasing incidence of multidrug-resistant strains, including resistance to last-resort antibiotics, such as carbapenems. Resistances are often due to complex interplays of natural and acquired resistance mechanisms that are enhanced by its large regulatory network. This study describes the proteomic responses of two carbapenem-resistant P. aeruginosa strains of high-risk clones ST235 and ST395 to subminimal inhibitory concentrations (sub-MICs) of meropenem by identifying differentially regulated proteins and pathways. Strain CCUG 51971 carries a VIM-4 metallo-β-lactamase or ‘classical’ carbapenemase; strain CCUG 70744 carries no known acquired carbapenem-resistance genes and exhibits ‘non-classical’ carbapenem-resistance. Strains were cultivated with different sub-MICs of meropenem and analyzed, using quantitative shotgun proteomics based on tandem mass tag (TMT) isobaric labeling, nano-liquid chromatography tandem-mass spectrometry and complete genome sequences. Exposure of strains to sub-MICs of meropenem resulted in hundreds of differentially regulated proteins, including β-lactamases, proteins associated with transport, peptidoglycan metabolism, cell wall organization, and regulatory proteins. Strain CCUG 51971 showed upregulation of intrinsic β-lactamases and VIM-4 carbapenemase, while CCUG 70744 exhibited a combination of upregulated intrinsic β-lactamases, efflux pumps, penicillin-binding proteins and downregulation of porins. All components of the H1 type VI secretion system were upregulated in strain CCUG 51971. Multiple metabolic pathways were affected in both strains. Sub-MICs of meropenem cause marked changes in the proteomes of carbapenem-resistant strains of P. aeruginosa exhibiting different resistance mechanisms, involving a wide range of proteins, many uncharacterized, which might play a role in the susceptibility of P. aeruginosa to meropenem.

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  • 32.
    Salva Serra, Francisco
    et al.
    University of the Balearic Islands, Spain; University of Gothenburg, Sweden.
    Pérez-Pantoja, Danilo
    Universidad Tecnológica Metropolitana, Chile.
    Donoso, Raúl A.
    Universidad Tecnológica Metropolitana, Chile; Center of Applied Ecology and Sustainability, Chile.
    Jaén-Luchoro, Daniel
    University of the Balearic Islands, Spain; University of Gothenburg, Sweden.
    Fernández-Juárez, Víctor
    University of Copenhagen, Denmark.
    Engström-Jakobsson, Hedvig
    University of Gothenburg, Sweden.
    Moore, Edward R. B.
    University of Gothenburg, Sweden.
    Lalucat, Jorge
    University of the Balearic Islands, Spain.
    Bennasar-Figueras, Antoni
    University of the Balearic Islands, Spain.
    Comparative genomics of Stutzerimonas balearica (Pseudomonas balearica): diversity, habitats, and biodegradation of aromatic compounds2023Ingår i: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 14, artikel-id 1159176Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stutzerimonas balearica (Pseudomonas balearica) has been found principally in oil-polluted environments. The capability of S. balearica to thrive from the degradation of pollutant compounds makes it a species of interest for potential bioremediation applications. However, little has been reported about the diversity of S. balearica. In this study, genome sequences of S. balearica strains from different origins were analyzed, revealing that it is a diverse species with an open pan-genome that will continue revealing new genes and functionalities as the genomes of more strains are sequenced. The nucleotide signatures and intra- and inter-species variation of the 16S rRNA genes of S. balearica were reevaluated. A strategy of screening 16S rRNA gene sequences in public databases enabled the detection of 158 additional strains, of which only 23% were described as S. balearica. The species was detected from a wide range of environments, although mostly from aquatic and polluted environments, predominantly related to petroleum oil. Genomic and phenotypic analyses confirmed that S. balearica possesses varied inherent capabilities for aromatic compounds degradation. This study increases the knowledge of the biology and diversity of S. balearica and will serve as a basis for future work with the species.

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  • 33. Willquist, Karin
    et al.
    Pawar, Sudhanshu
    Van Niel, Ed W. J.
    Reassessment of hydrogen tolerance in Caldicellulosiruptor saccharolyticus.2011Ingår i: Microbial Cell Factories, ISSN 1475-2859, E-ISSN 1475-2859, Vol. 10, artikel-id 111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Caldicellulosiruptor saccharolyticus has the ability to produce hydrogen (H2) at high yields from a wide spectrum of carbon sources, and has therefore gained industrial interest. For a cost-effective biohydrogen process, the ability of an organism to tolerate high partial pressures of H2 (PH2) is a critical aspect to eliminate the need for continuous stripping of the produced H2 from the bioreactor.

    RESULTS: Herein, we demonstrate that, under given conditions, growth and H2 production in C. saccharolyticus can be sustained at PH2 up to 67 kPa in a chemostat. At this PH2, 38% and 16% of the pyruvate flux was redirected to lactate and ethanol, respectively, to maintain a relatively low cytosolic NADH/NAD ratio (0.12 mol/mol). To investigate the effect of the redox ratio on the glycolytic flux, a kinetic model describing the activity of the key glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), was developed. Indeed, at NADH/NAD ratios of 0.12 mol/mol (Ki of NADH = 0.03 ± 0.01 mM) GAPDH activity was inhibited by only 50% allowing still a high glycolytic flux (3.2 ± 0.4 mM/h). Even at high NADH/NAD ratios up to 1 mol/mol the enzyme was not completely inhibited. During batch cultivations, hydrogen tolerance of C. saccharolyticus was dependent on the growth phase of the organism as well as the carbon and energy source used. The obtained results were analyzed, based on thermodynamic and enzyme kinetic considerations, to gain insight in the mechanism underlying the unique ability of C. saccharolyticus to grow and produce H2 under relatively high PH2.

    CONCLUSION: C. saccharolyticus is able to grow and produce hydrogen at high PH2, hence eliminating the need of gas sparging in its cultures. Under this condition, it has a unique ability to fine tune its metabolism by maintaining the glycolytic flux through regulating GAPDH activity and redistribution of pyruvate flux. Concerning the later, xylose-rich feedstock should be preferred over the sucrose-rich one for better H2 yield.

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