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Olszewska-Widdrat, A., Xiros, C., Wallenius, A., Schneider, R., Rios da Costa Pereira, L. P. & Venus, J. (2023). Bioprocess optimization for lactic and succinic acid production from a pulp and paper industry side stream. Frontiers in Bioengineering and Biotechnology, 11, Article ID 1176043.
Open this publication in new window or tab >>Bioprocess optimization for lactic and succinic acid production from a pulp and paper industry side stream
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2023 (English)In: Frontiers in Bioengineering and Biotechnology, E-ISSN 2296-4185, Vol. 11, article id 1176043Article in journal (Refereed) Published
Abstract [en]

The effective and cheap production of platform chemicals is a crucial step towards the transition to a bio-based economy. In this work, biotechnological methods using sustainable, cheap, and readily available raw materials bring bio-economy and industrial microbiology together: Microbial production of two platform chemicals is demonstrated [lactic (LA) and succinic acid (SA)] from a non-expensive side stream of pulp and paper industry (fibre sludge) proposing a sustainable way to valorize it towards economically important monomers for bioplastics formation. This work showed a promising new route for their microbial production which can pave the way for new market expectations within the circular economy principles. Fibre sludge was enzymatically hydrolysed for 72 h to generate a glucose rich hydrolysate (100 g·L−1 glucose content) to serve as fermentation medium for Bacillus coagulans A 541, A162 strains and Actinobacillus succinogenis B1, as well as Basfia succiniciproducens B2. All microorganisms were investigated in batch fermentations, showing the ability to produce either lactic or succinic acid, respectively. The highest yield and productivities for lactic production were 0.99 g·g−1 and 3.75 g·L−1·h−1 whereas the succinic acid production stabilized at 0.77 g·g−1 and 1.16 g·L−1·h−1. Copyright © 2023 Olszewska-Widdrat, Xiros, Wallenius, Schneider, Rios da Costa Pereira and Venus.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2023
Keywords
bioeconomy, fermentation, fibre sludge, hydrolysate, lactic acid, succinic acid, Bacteriology, Glucose, Industrial chemicals, Paper and pulp industry, Pulp, Acid production, Bio-based, Bioprocess optimization, Fiber sludge, Microbial production, Platform chemicals, Pulp and paper industry, Side streams, Succinic acids
National Category
Bioprocess Technology
Identifiers
urn:nbn:se:ri:diva-65548 (URN)10.3389/fbioe.2023.1176043 (DOI)2-s2.0-85161057437 (Scopus ID)
Note

This work was funded from the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 952941 (BIOMAC Project).

Available from: 2023-06-28 Created: 2023-06-28 Last updated: 2023-12-22Bibliographically approved
Bakratsas, G., Polydera, A., Nilson, O., Chatzikonstantinou, A., Xiros, C., Katapodis, P. & Stamatis, H. (2023). Mycoprotein Production by Submerged Fermentation of the Edible Mushroom Pleurotus ostreatus in a Batch Stirred Tank Bioreactor Using Agro-Industrial Hydrolysate. Foods, 12(12), Article ID 2295.
Open this publication in new window or tab >>Mycoprotein Production by Submerged Fermentation of the Edible Mushroom Pleurotus ostreatus in a Batch Stirred Tank Bioreactor Using Agro-Industrial Hydrolysate
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2023 (English)In: Foods, E-ISSN 2304-8158, Vol. 12, no 12, article id 2295Article in journal (Refereed) Published
Abstract [en]

The demand for cheap, healthy, and sustainable alternative protein sources has turned research interest into microbial proteins. Mycoproteins prevail due to their quite balanced amino acid profile, low carbon footprint and high sustainability potential. The goal of this research was to investigate the capability of Pleurotus ostreatus to metabolize the main sugars of agro-industrial side streams, such as aspen wood chips hydrolysate, to produce high-value protein with low cost. Our results indicate that P. ostreatus LGAM 1123 could be cultivated both in a C-6 (glucose)- and C-5(xylose)-sugar-containing medium for mycoprotein production. A mixture of glucose and xylose was found to be ideal for biomass production with high protein content and rich amino acid profile. P. ostreatus LGAM 1123 cultivation in a 4 L stirred-tank bioreactor using aspen hydrolysate was achieved with 25.0 ± 3.4 g L−1 biomass production, 1.8 ± 0.4 d−1 specific growth rate and a protein yield of 54.5 ± 0.5% (g/100 g sugars). PCA analysis of the amino acids revealed a strong correlation between the amino acid composition of the protein produced and the ratios of glucose and xylose in the culture medium. The production of high-nutrient mycoprotein by submerged fermentation of the edible fungus P. ostreatus using agro-industrial hydrolysates is a promising bioprocess in the food and feed industry. © 2023 by the authors.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
agro-industrial hydrolysate, amino acid metabolism, bioreactors, single-cell protein, submerged cultivation
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:ri:diva-65722 (URN)10.3390/foods12122295 (DOI)2-s2.0-85163872480 (Scopus ID)
Note

This study was co-financed by the European Regional Development Fund of the European Union and Greek National Funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH-CREATE-INNOVATE (project code: Τ2EDK-02830).

Available from: 2023-08-08 Created: 2023-08-08 Last updated: 2023-08-08Bibliographically approved
Bakratsas, G., Polydera, A., Nilson, O., Kossatz, L., Xiros, C., Katapodis, P. & Stamatis, H. (2023). Single-cell protein production by Pleurotus ostreatus in submerged fermentation†. Sustainable Food Technology, 1(3), 377-389
Open this publication in new window or tab >>Single-cell protein production by Pleurotus ostreatus in submerged fermentation†
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2023 (English)In: Sustainable Food Technology, ISSN 2753-8095, Vol. 1, no 3, p. 377-389Article in journal (Refereed) Published
Abstract [en]

Agricultural land shrinkage, decreasing global water resources, population increase and malnutrition highlight the need for new food sources. Single-cell protein derived from microorganisms could be a solution to high protein demand. The aim of this work was to optimize the cultivation conditions for single-cell protein production by Pleurotus ostreatus LGAM 1123 in submerged cultures and valorize fiber sludge, a low cost industrial side stream from the pulp and paper industry, as a substrate for single-cell protein (SCP) production. A study on the effect of different cultivation conditions on fungal growth and protein production has been conducted. Response surface methodology was used to investigate the combined effect of the most important factors (glucose and yeast extract medium concentrations) and optimize the process. A maximum protein production of 10.0 ± 0.9 g L-1 was found for the submerged cultivation of the fungus in a 3.5 L stirred-tank bioreactor, while the biomass produced and its total protein content were 26.0 ± 2.0 g L-1 and 44.8 ± 0.8%, respectively. As an industrial application, a cellulosic hydrolysate obtained after enzymatic hydrolysis of fibre sludge in the optimized medium composition was used. Fibre sludge was shown to be an excellent feedstock for SCP production achieving productivity and protein content very similar to glucose fermentations. Single-cell protein of P. ostreatus presented higher amino acid scores compared to the recommended ones for valine, leucine, and aromatic amino acids in human nutrition. Therefore, P. ostreatus biomass could stand as an alternative vegan protein source due to its high protein content and amino acid composition. 

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2023
National Category
Industrial Biotechnology
Identifiers
urn:nbn:se:ri:diva-69466 (URN)10.1039/d2fb00058j (DOI)2-s2.0-85163812744 (Scopus ID)
Note

“Co-financed by the European Regional Development Fund of the European Union and Greek National Funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code: T2EDK-02830)”.

Available from: 2024-01-15 Created: 2024-01-15 Last updated: 2024-05-21Bibliographically approved
Xiros, C., Shahab, R. & Studer, M. (2019). A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome. Applied Microbiology and Biotechnology, 103(8), 3355-3365
Open this publication in new window or tab >>A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome
2019 (English)In: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 103, no 8, p. 3355-3365Article in journal (Refereed) Published
Abstract [en]

The ability of the multispecies biofilm membrane reactors (MBM reactors) to provide distinguished niches for aerobic and anaerobic microbes at the same time was used for the investigation of the consolidated bioprocessing of cellulose to short chain fatty acids (SCFAs). A consortium based consolidated bioprocess (CBP) was designed. The rumen microbiome was used as the converting microbial consortium, co-cultivated with selected individual aerobic fungi which formed a biofilm on the tubular membrane flushed with oxygen. The beneficial effect of the fungal biofilm on the process yields and productivities was attributed to the enhanced cellulolytic activities compared with those achieved by the rumen microbiome alone. At 30 °C, the MBM system with Trichoderma reesei biofilm reached a concentration 39% higher (7.3 g/L SCFAs), than the rumen microbiome alone (5.1 g/L) using 15 g/L crystalline cellulose as the substrate. Fermentation temperature was crucial especially for the composition of the short chain fatty acids produced. The temperature increase resulted in shorter fatty acids produced. While a mixture of acetic, propionic, butyric, and caproic acids was produced at 30 °C with Trichoderma reesei biofilm, butyric and caproic acids were not detected during the fermentations at 37.5 °C carried out with Coprinopsis cinerea as the biofilm forming fungus. Apart from the presence of the fungal biofilm, no parameter studied had a significant impact on the total yield of organic acids produced, which reached 0.47 g of total SCFAs per g of cellulose (at 30 °C and at pH 6, with rumen inoculum to total volume ratio equal to 0.372).

Keywords
Acetic acid, Biofilms, Butyric acid, Coprinopsis cinerea, Membrane reactors, Trichoderma reesei, Bioreactors, Cellulose, Fermentation, Fungi, Propionic acid, Consolidated bio-processing, Fermentation temperature, Membrane reactor, Multi-species biofilms, Short chain fatty acids (SCFAs), Short-chain fatty acids, Fatty acids
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38235 (URN)10.1007/s00253-019-09706-1 (DOI)2-s2.0-85062795288 (Scopus ID)
Available from: 2019-03-27 Created: 2019-03-27 Last updated: 2023-05-11Bibliographically approved
Svensson, E., Lundberg, V., Jansson, M., Xiros, C. & Berntsson, T. (2016). The effect of high solids loading in ethanol production integrated with a pulp mill. Chemical engineering research & design, 111, 387-402
Open this publication in new window or tab >>The effect of high solids loading in ethanol production integrated with a pulp mill
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2016 (English)In: Chemical engineering research & design, ISSN 0263-8762, E-ISSN 1744-3563, Vol. 111, p. 387-402Article in journal (Refereed) Published
Abstract [en]

In this paper, two ethanol processes integrated with a softwood pulp mill are compared with regard to their steam demand, process integration potential and profitability. The processes differ in the solids loading in the simultaneous saccharification and fermentation step and in the resulting ethanol concentration. The results show that a higher ethanol concentration does not necessarily lead to significant reductions in steam demand. Instead, it is demonstrated that the steam demand for distillation is highly dependent on the design of the distillation plant. Nevertheless, a higher solids loading (high gravity) can be beneficial for the treatment of the stillage from the distillation plant. A higher solids loading results either in a lower steam demand for evaporation of the stillage or possibly in a reduced demand for effluent treatment compared to a conventional solids loading process. While the results show that a higher ethanol concentration leads to advantages in energy costs and investment costs for the distillation plant, they also show that the potential benefits of a high-gravity process are offset by the expected decrease in ethanol yield, which leads to higher raw material costs.

Keywords
Biorefinery, Ethanol, High gravity, Pinch analysis, Pulp mill, Techno-economic assessment
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-12634 (URN)10.1016/j.cherd.2016.05.026 (DOI)2-s2.0-84979298728 (Scopus ID)
Available from: 2016-09-15 Created: 2016-09-15 Last updated: 2023-05-11Bibliographically approved
Johansson, E., Xiros, C. & Larsson, C. (2014). Fermentation performance and physiology of two strains of Saccharomyces cerevisiae during growth in high gravity spruce hydrolysate and spent sulphite liquor. BMC Biotechnology, 14, Article ID Art no 47.
Open this publication in new window or tab >>Fermentation performance and physiology of two strains of Saccharomyces cerevisiae during growth in high gravity spruce hydrolysate and spent sulphite liquor
2014 (English)In: BMC Biotechnology, E-ISSN 1472-6750, Vol. 14, article id Art no 47Article in journal (Refereed) Published
Abstract [en]

Background: Lignocellulosic materials are a diverse group of substrates that are generally scarce in nutrients, which compromises the tolerance and fermentation performance of the fermenting organism. The problem is exacerbated by harsh pre-treatment, which introduces sugars and substances inhibitory to yeast metabolism. This study compares the fermentation behaviours of two yeast strains using different types of lignocellulosic substrates; high gravity dilute acid spruce hydrolysate (SH) and spent sulphite liquor (SSL), in the absence and presence of yeast extract. To this end, the fermentation performance, energy status and fermentation capacity of the strains were measured under different growth conditions.Results: Nutrient supplementation with yeast extract increased sugar uptake, cell growth and ethanol production in all tested fermentation conditions, but had little or no effect on the energy status, irrespective of media. Nutrient-supplemented medium enhanced the fermentation capacity of harvested cells, indicating that cell viability and reusability was increased by nutrient addition.Conclusions: Although both substrates belong to the lignocellulosic spruce hydrolysates, their differences offer specific challenges and the overall yields and productivities largely depend on choice of fermenting strain.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-184 (URN)10.1186/1472-6750-14-47 (DOI)2-s2.0-84901634198 (Scopus ID)
Available from: 2016-06-13 Created: 2016-06-13 Last updated: 2024-01-10Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3443-8038

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