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Cheregi, O., Ekendahl, S., Engelbrektsson, J., Strömberg, N., Godhe, A. & Spetea, C. (2019). Microalgae biotechnology in Nordic countries – the potential of local strains. Physiologia Plantarum: An International Journal for Plant Biology, 166(1), 438-450
Open this publication in new window or tab >>Microalgae biotechnology in Nordic countries – the potential of local strains
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2019 (English)In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 166, no 1, p. 438-450Article in journal (Refereed) Published
Abstract [en]

Climate change, energy use and food security are the main challenges that our society is facing nowadays. Biofuels and feedstock from microalgae can be part of the solution if high and continuous production is to be ensured. This could be attained in year-round, low cost, outdoor cultivation systems using strains that are not only champion producers of desired compounds but also have robust growth in a dynamic climate. Using microalgae strains adapted to the local conditions may be advantageous particularly in Nordic countries. Here, we review the current status of laboratory and outdoor-scale cultivation in Nordic conditions of local strains for biofuel, high-value compounds and water remediation. Strains suitable for biotechnological purposes were identified from the large and diverse pool represented by saline (NE Atlantic Ocean), brackish (Baltic Sea) and fresh water (lakes and rivers) sources. Energy-efficient annual rotation for cultivation of strains well adapted to Nordic climate has the potential to provide high biomass yields for biotechnological purposes

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38263 (URN)10.1111/ppl.12951 (DOI)2-s2.0-85063336382 (Scopus ID)
Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-07-01Bibliographically approved
Moen, I., Ugland, H., Strömberg, N., Sjöström, E., Karlsson, A., Ringstad, L., . . . Hagleröd, C. (2018). Development of a novel in situ gelling skin dressing: Deliveringhigh levels of dissolved oxygen at pH 5.5. Health Sci Rep., Article ID e57.
Open this publication in new window or tab >>Development of a novel in situ gelling skin dressing: Deliveringhigh levels of dissolved oxygen at pH 5.5
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2018 (English)In: Health Sci Rep., article id e57Article in journal (Refereed) Published
Abstract [en]

Background and aims: Wound healing requires appropriate oxygen and pH levels.Oxygen therapy and pH‐modulating treatments have shown positive effects onwound healing. Thus, a dressing, which combines high levels of dissolved oxygen(DO) with the pH of intact skin, may improve wound healing. Our aims were to (1) formulatean in situ gelling dressing with high levels of DO and with the pH level of intactskin, (2) evaluate physical and chemical properties of the dressing, and (3) elucidatebasic effects of elevated levels of DO on human skin cells in vitro.Methods: A dressing was formulated with 15 to 16 wt% poloxamer 407, acetatebuffer, and oxygenated water. Stability of pH and DO, rheology, and shelf life wereanalysed. Furthermore, in vitro studies of the effect of increased levels of DO wereperformed.Results: An in situ gelling wound dressing, with a DO concentration rangingbetween 25 and 35 mg/L and a pH of 5.5, was formulated. The DO concentrationwas stable above 22 mg/L for at least 30 hours when applied on a surface at 35°Cand covered for directed diffusion into the intended wound area. At storage, thedressing had stable pH for 3 months and stable DO concentration over 30 mg/L for7 weeks. Increasing DO significantly enhanced intracellular ATP in human skin cells,without changing reactive oxygen species production, proliferation rate, or viability.Conclusion: The developed dressing may facilitate wound healing by deliveringcontrolled and stable oxygen levels, providing adjustable pH for optimized healing,and increasing intracellular ATP availability.

Keywords
hyperoxia, intracellular ATP, thermo sensitive, topical dressing, wound healing
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34880 (URN)10.1002/hsr2.57 (DOI)
Note

Eurostars project, Grant/Award Number: E!10397

Available from: 2018-08-21 Created: 2018-08-21 Last updated: 2019-06-18
Ekendahl, S., Bark, M., Engelbrektsson, J., Karlsson, C.-A., Niyitegeka, D. & Strömberg, N. (2018). Energy-efficient outdoor cultivation of oleaginous microalgae at northern latitudes using waste heat and flue gas from a pulp and paper mill. Algal Research, 31, 138-146
Open this publication in new window or tab >>Energy-efficient outdoor cultivation of oleaginous microalgae at northern latitudes using waste heat and flue gas from a pulp and paper mill
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2018 (English)In: Algal Research, ISSN 2211-9264, Vol. 31, p. 138-146Article in journal (Refereed) Published
Abstract [en]

Energy efficient cultivation is the major bottleneck for microalgal biomass production on a large scale and considered very difficult to attain at northern latitudes. In this study an unconventional method for industrial microalgae cultivation for bio-oil production using pulp and paper mill waste resources while harvesting only once a year was performed, mainly in order to investigate the energy efficiency of the process. Algae were cultivated for three months in 2014 in covered pond systems with access to flue gas and waste heat from the industry, and the biomass was recovered as thick sediment sludge after dewatering. The cultivation systems, designed to manage the waste resources, reached a promising photosynthetic efficiency of at most 1.1%, a net energy ratio (NER) of 0.25, and a projected year-round energy biomass yield per area 5.2 times higher than corresponding rapeseed production at the location. Thus, microalgae cultivation was, for the first time, proven energy efficient in a cold continental climate. Energy-rich indigenous communities quickly out-competed the oleaginous monocultures used for inoculation. The recovered biomass had higher heating values of 20–23 MJ kg− 1 and contained 14–19% oil dominated by C16 followed by C18 fatty acids. The cultivation season at 59°15′N, 14°18′E was projected to be efficient for 10 months and waste heat drying of the biomass is suggested for two winter months. The technique is proposed for carbon sequestering and energy storage in the form of microalgal sludge or dry matter for later conversion into biochemicals.

Keywords
Autotrophic, Energy efficiency, Flue gas, Lipids, Microalgae, Pulp and paper
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33428 (URN)10.1016/j.algal.2017.11.007 (DOI)2-s2.0-85041819849 (Scopus ID)
Note

Funding details: 2012-03987, VINNOVA

Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2019-06-27Bibliographically approved
Hakonen, A. & Strömberg, N. (2018). Fluorescence and naked-eye detection of Pb2+ in drinkingwater using a low-cost ionophore based sensing scheme. Chemosensors, 6(4), Article ID 51.
Open this publication in new window or tab >>Fluorescence and naked-eye detection of Pb2+ in drinkingwater using a low-cost ionophore based sensing scheme
2018 (English)In: Chemosensors, ISSN 2227-9040, Vol. 6, no 4, article id 51Article in journal (Refereed) Published
Abstract [en]

Drinking water contamination of lead from various environmental sources, leaching consumer products, and intrinsic water-pipe infrastructure is still today a matter of great concern. Therefore, new highly sensitive and convenient Pb2+ measurement schemes are necessary, especially for in-situ measurements at a low cost. Within this work dye/ionophore/Pb2+ co-extraction and effective water phase de-colorization was utilized for highly sensitive lead measurements and sub-ppb naked-eye detection. A low-cost ionophore Benzo-18-Crown-6-ether was used, and a simple test-tube mix and separate procedure was developed. Instrumental detection limits were in the low ppt region (LOD = 3, LOQ = 10), and naked-eye detection was 500 ppt. Note, however, that this sensing scheme still has improvement potential as concentrations of fluorophore and ionophore were not optimized. Artificial tap-water samples, leached by a standardized method, demonstrated drinking water application. Implications for this method are convenient in-situ lead ion measurements.

Keywords
Benzo-18-Crown-6-ether, Drinking water, Fluorescence detection, Ionophore, Lead ions
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37024 (URN)10.3390/chemosensors6040051 (DOI)2-s2.0-85059237254 (Scopus ID)
Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-06-18Bibliographically approved
Strömberg, N., Eriksson, H. & Saramat, A. (2014). Determination of phase separation efficiency for biodiesel quality and blending (ed.). Fuel, 117(pt A), 74-78
Open this publication in new window or tab >>Determination of phase separation efficiency for biodiesel quality and blending
2014 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 117, no pt A, p. 74-78Article in journal (Refereed) Published
Abstract [en]

In this study we reintroduce phase separation efficiency as an important characteristic for biodiesel quality and blending. The ability of the fuel to emulsify water is possibly one of the most important features behind biological and chemical fuel degradation but yet, no methods that directly measure this property are included in the standard biodiesel regulation EN14214. The proposed simple technique for fuel quality testing is based on the time it takes for ultra-purified water to become transparent after complete mixing with an equal volume of fuel, measured by kinetic absorbance spectrophotometry. In this study we screen the phase separation efficiency (measured as separation time) of purified, un-aged and aged Fatty Acid Methyl Esters (FAME/B100) and its blends with EN590 with 7% FAME without detergents (B7 reference fuel Euro VI Part no 546061-35 and B100) as well as for FAME blends with a commercial EN590. The B7 fuel was used as reference in all measurements. Aged biodiesel (FAME/B100) almost doubled (1.8 times) its separation time compared to the un-aged FAME/B100 sample and had almost three times (2.9) longer phase separationtime relative the reference B7 fuel. Also fuel blends showed long separation times. A fuel blend based on aged FAME/B100 blended with B7 to a corresponding B30 (30% FAME) gave after three consecutive 10 s mixings stable emulsions (>30 min) in two out of three replicates. All fuels blended with commercial EN590 showed excellent phase separation efficiencies with significantly shorter separation times than FAME/B100. We also show that the phase separation efficiency of the B30 blend could be improved after the rape seed ester was vacuum distilled before blending with B7 petrodiesel. The results indicate that likely emulsion problems associated with the B30 blends can be circumvented with proper selection of compatible petroleum components as well as FAME purifications.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6678 (URN)10.1016/j.fuel.2013.07.078 (DOI)2-s2.0-84886532937 (Scopus ID)23657 (Local ID)23657 (Archive number)23657 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-08-15Bibliographically approved
Strömberg, N. (2014). Digital colour tone for fluorescence sensing: A direct comparison of intensity, ratiometric and hue based quantification (ed.). The Analyst, 139(14), 3524-3527
Open this publication in new window or tab >>Digital colour tone for fluorescence sensing: A direct comparison of intensity, ratiometric and hue based quantification
2014 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 139, no 14, p. 3524-3527Article in journal (Refereed) Published
Abstract [en]

The hue parameter of HSV colour-space for digital imaging is shown to be accessible for convenient quantitative fluorescence imaging. A commercially available pH probe was utilized in solution and incorporated into optical μ-sensors for microscopy applications.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6734 (URN)10.1039/c4an00063c (DOI)2-s2.0-84902530559 (Scopus ID)23748 (Local ID)23748 (Archive number)23748 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-08-08Bibliographically approved
Strömberg, N. (2013). Biodiesel degradation rate after refueling (ed.). Fuel, 105(Mar), 301-305
Open this publication in new window or tab >>Biodiesel degradation rate after refueling
2013 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 105, no Mar, p. 301-305Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6535 (URN)23814 (Local ID)23814 (Archive number)23814 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-06-18Bibliographically approved
Ekendahl, S., Strömberg, N., Haglund, J., Lauritzen, A., Persson, M., Sandberg, M., . . . Pettersson, C. (2012). Algodling hos massa- och pappersbruk för hållbar produktion av biobränsle – en förstudie (ed.). Paper presented at .
Open this publication in new window or tab >>Algodling hos massa- och pappersbruk för hållbar produktion av biobränsle – en förstudie
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2012 (Swedish)Report (Refereed)
Publisher
p. 62
Series
SP Rapport, ISSN 0284-5172 ; 2012:15
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-5039 (URN)13694 (Local ID)13694 (Archive number)13694 (OAI)
Available from: 2016-09-07 Created: 2016-09-07 Last updated: 2019-06-20Bibliographically approved
Strömberg, N. & Sahlin, E. (2012). Determination of the short-chain fatty acid pattern in biodiesel using high throughput syringe solvent extraction and ion exclusion chromatography (ed.). Fuel, 97, 531-535
Open this publication in new window or tab >>Determination of the short-chain fatty acid pattern in biodiesel using high throughput syringe solvent extraction and ion exclusion chromatography
2012 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 97, p. 531-535Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6402 (URN)23927 (Local ID)23927 (Archive number)23927 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-06-18Bibliographically approved
Strömberg, N. (2012). Diffusion consistent calibrations for improved chemical imaging using nanoparticle enhanced optical sensors (ed.). The Analyst, 137(2), 315-321
Open this publication in new window or tab >>Diffusion consistent calibrations for improved chemical imaging using nanoparticle enhanced optical sensors
2012 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 137, no 2, p. 315-321Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6425 (URN)23972 (Local ID)23972 (Archive number)23972 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-06-18Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6383-8319

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