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Publications (10 of 10) Show all publications
Cheregi, O., Pinder, M. I. .., Shaikh, K. M., Andersson, M. X., Engelbrektsson, J., Strömberg, N., . . . Spetea, C. (2023). Transcriptome analysis reveals insights into adaptive responses of two marine microalgae species to Nordic seasons. Algal Research, Article ID 103222.
Open this publication in new window or tab >>Transcriptome analysis reveals insights into adaptive responses of two marine microalgae species to Nordic seasons
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2023 (English)In: Algal Research, ISSN 2211-9264, article id 103222Article in journal (Refereed) Published
Abstract [en]

There is an increasing interest in algae-based biomass produced outdoors in natural and industrial settings for biotechnological applications. To predict the yield and biochemical composition of the biomass, it is important to understand how the transcriptome of species and strains of interest is affected by seasonal changes. Here we studied the effects of Nordic winter and summer on the transcriptome of two phytoplankton species, namely the diatom Skeletonema marinoi (Sm) and the eustigmatophyte Nannochloropsis granulata (Ng), recently identified as potentially important for biomass production on the west coast of Sweden. Cultures were grown in photobioreactors in simulated Nordic summer and winter, and the gene expression in two phases was quantified by Illumina RNA-sequencing. Five paired comparisons were made among the four conditions. Sm was overall more responsive to seasons since 70 % of the total transcriptome (14,783 genes) showed differential expression in at least one comparison as compared to 1.6 % (1403 genes) for Ng. For both species, we observed larger differences between the seasons than between the phases of the same season. In summer phase 1, Sm cells focused on photosynthesis and polysaccharide biosynthesis. Nitrate assimilation and recycling of intracellular nitrogen for protein biosynthesis were more active in summer phase 2 and throughout winter. Lipid catabolism was upregulated in winter relative to summer to supply carbon for respiration. Ng favored lipid accumulation in summer, while in winter activated different lipid remodeling pathways as compared to Sm. To cope with winter, Ng upregulated breakdown and transport of carbohydrates for energy production. Taken together, our transcriptome data reveal insights into adaptive seasonal responses of Sm and Ng important for biotechnological applications on the west coast of Sweden, but more work is required to decipher the molecular mechanisms behind these responses.

National Category
Bioenergy
Identifiers
urn:nbn:se:ri:diva-66348 (URN)10.1016/j.algal.2023.103222 (DOI)
Note

This work was supported by the Swedish Energy Agency (P45907-1, to C.S.), the Swedish Research Council (2018-04555, to M.T.) and the Swedish Research Council for Sustainable Development (2017-00466, to M.T.). K.M.S. was recipient of a postdoctoral fellowship from the Carl Tryggers Foundation (CTS20:406).

Available from: 2023-09-06 Created: 2023-09-06 Last updated: 2023-09-06Bibliographically approved
Cheregi, O., Engelbrektsson, J., Andersson, M., Strömberg, N., Ekendahl, S., Godhe, A. & Spetea, C. (2021). Marine microalgae for outdoor biomass production—A laboratory study simulating seasonal light and temperature for the west coast of Sweden. Physiologia Plantarum, 173(2), 543-554
Open this publication in new window or tab >>Marine microalgae for outdoor biomass production—A laboratory study simulating seasonal light and temperature for the west coast of Sweden
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2021 (English)In: Physiologia Plantarum, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 173, no 2, p. 543-554Article in journal (Refereed) Published
Abstract [en]

At Nordic latitudes, year-round outdoor cultivation of microalgae is debatable due to seasonal variations in productivity. Shall the same species/strains be used throughout the year, or shall seasonal-adapted ones be used? To elucidate this, a laboratory study was performed where two out of 167 marine microalgal strains were selected for intended cultivation at the west coast of Sweden. The two local strains belong to Nannochloropsis granulata (Ng) and Skeletonema marinoi (Sm142). They were cultivated in photobioreactors and compared in conditions simulating variations in light and temperature of a year divided into three growth seasons (spring, summer and winter). The strains grew similarly well in summer (and also in spring), but Ng produced more biomass (0.225 vs. 0.066 g DW L−1 day−1) which was more energy rich (25.0 vs. 16.6 MJ kg−1 DW). In winter, Sm142 grew faster and produced more biomass (0.017 vs. 0.007 g DW L−1 day−1), having similar energy to the other seasons. The higher energy of the Ng biomass is attributed to a higher lipid content (40 vs. 16% in summer). The biomass of both strains was richest in proteins (65%) in spring. In all seasons, Sm142 was more effective in removing phosphorus from the cultivation medium (6.58 vs. 4.14 mg L−1 day−1 in summer), whereas Ng was more effective in removing nitrogen only in summer (55.0 vs. 30.8 mg L−1 day−1). Our results suggest that, depending on the purpose, either the same or different local species can be cultivated, and are relevant when designing outdoor studies. © 2021 The Authors. 

Place, publisher, year, edition, pages
Blackwell Publishing Ltd, 2021
National Category
Ecology
Identifiers
urn:nbn:se:ri:diva-53026 (URN)10.1111/ppl.13412 (DOI)2-s2.0-85104504824 (Scopus ID)
Note

Funding details: CTS 16:437, KF 17:19; Funding details: Carl Tryggers Stiftelse för Vetenskaplig Forskning; Funding details: Energimyndigheten; Funding text 1: This work was supported by the Swedish Energy Agency and Carl Tryggers Foundation (Cornelia Spetea). Otilia Cheregi was a recipient of a postdoctoral fellowship from the Carl Tryggers Foundation during 2016–2018. We acknowledge Olga Kourtchenko (Department Marine Sciences, University of Gothenburg) for providing the strains from the GUMACC collection as well as feedback to the manuscript. We thank Mathias Berglund at RISE for the elementary content and calorific value determination. We are grateful to the reviewers for their constructive suggestions.; Funding text 2: Carl Tryggers Foundation for Scientific Research, Grant/Award Numbers: CTS 16:437, KF 17:19; Swedish Energy Council, Grant/Award Number: P45907‐1 

Available from: 2021-05-25 Created: 2021-05-25 Last updated: 2022-07-12Bibliographically approved
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, 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, 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: 2022-05-10Bibliographically approved
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
Mayers, J., Vaiciulyte, S., Malmhall-Bah, E., Alcaide-Sancho, J., Ewald, S., Godhe, A., . . . Albers, E. (2018). Identifying a marine microalgae with high carbohydrate productivities under stress and potential for efficient flocculation. Algal Research, 31, 430-442
Open this publication in new window or tab >>Identifying a marine microalgae with high carbohydrate productivities under stress and potential for efficient flocculation
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2018 (English)In: Algal Research, ISSN 2211-9264, Vol. 31, p. 430-442Article in journal (Refereed) Published
Abstract [en]

Microalgal biomass represents a potential third generation feedstock that could be utilised as a source of carbohydrates for fermentative production of a range of platform biochemicals. Identifying microalgal strains with high biomass and carbohydrate productivities while also being amenable to downstream processes is key in improving the feasibility of these processes. Utilising marine microalgae capable of growing in seawater will decrease reliance on freshwater resources and improve the sustainability of production. This study screened several marine microalgae believed to accumulate carbohydrates to find new high performing strains. Four strains had high growth rates and accumulated carbohydrates > 35% DW under stress. The strain Chlorella salina demonstrated the highest biomass and carbohydrate productivity, and alkaline autoflocculation (4 mM NaOH) enabled biomass recoveries > 95% efficiency, resulting in an 8-10 x concentration of the culture. Under nutrient replete conditions, biomass productivity reached 0.6 g L-1 d(-1), significantly greater than that of nitrogen starved cultures. However, nitrogen starvation rapidly increased carbohydrate content to > 50% DW in 2 days, resulting in carbohydrate productivities > 0.20 g L-1 d(-1). Chlorella salina partitions the products of photosynthesis preferentially into carbohydrate synthesis under nitrogen starvation. A greater understanding of cellular physiology and carbon partitioning in response to nutrient stress will enable better control and optimisation of the bio-processes. This study has identified a potentially high performance marine microalga for carbohydrate production that is also amenable to low-cost harvesting.

Keywords
Marine microalgae, Chlorella, Carbohydrates, Flocculation, Nurient starvation, rbon allocation
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33823 (URN)10.1016/j.algal.2018.02.034 (DOI)2-s2.0-85043325350 (Scopus ID)
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2019-06-20Bibliographically approved
Røyne, F., Berlin, J., Ekendahl, S. & Albers, E. (2013). STATE OF THE ART OF ALGAL BIOMASS AS RAW MATERIAL FOR BIOFUEL PRODUCTION (ed.).
Open this publication in new window or tab >>STATE OF THE ART OF ALGAL BIOMASS AS RAW MATERIAL FOR BIOFUEL PRODUCTION
2013 (English)Report (Refereed)
Publisher
p. 41
Series
f3 rapport.
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-5594 (URN)16125 (Local ID)16125 (Archive number)16125 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2020-12-01Bibliographically 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.).
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: 2020-12-01Bibliographically approved
Olsson, M., Sárvári, I., Ekendahl, S., Brive, L., Luca Kovacs, E., Söderberg, P. & Edberg, A. (2011). Mikroskopiska alger som kombinerad koldioxidsänka och energikälla i Sverige (ed.).
Open this publication in new window or tab >>Mikroskopiska alger som kombinerad koldioxidsänka och energikälla i Sverige
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2011 (Swedish)Report (Other (popular science, discussion, etc.))
Series
Värmeforsk : SYS08-836
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-7033 (URN)12554 (Local ID)12554 (Archive number)12554 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2023-04-28Bibliographically approved
Jakubowicz, I., Yarahmadi, N., Jansson, A., Ekendahl, S., Eriksson, L. & Lindblad, C. (2006). Development of test procedure for the determination of disintegrability of plastic materials under conditions simulating small scale composting (ed.).
Open this publication in new window or tab >>Development of test procedure for the determination of disintegrability of plastic materials under conditions simulating small scale composting
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2006 (English)Report (Refereed)
Series
SP Rapport, ISSN 0284-5172 ; 2006:07
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-4708 (URN)6527 (Local ID)91-85303-91-7 (ISBN)6527 (Archive number)6527 (OAI)
Available from: 2016-09-07 Created: 2016-09-07 Last updated: 2023-05-26Bibliographically approved
Ekendahl, S. (2003). Characterization of yeasts isolated from deep igneous rock aquifers of the Fennoscandian Sheild (ed.). Microbiology and Ecology, 46, 416-428
Open this publication in new window or tab >>Characterization of yeasts isolated from deep igneous rock aquifers of the Fennoscandian Sheild
2003 (English)In: Microbiology and Ecology, Vol. 46, p. 416-428Article in journal (Refereed) Published
Abstract [en]

Characterization of yeasts isolated from deep igneous rock aquifers of the Fennoscandian Sheild

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-5843 (URN)2178 (Local ID)2178 (Archive number)2178 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2020-12-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9560-387x

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