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Patel, A. & Matsakas, L. (2019). A comparative study on de novo and ex novo lipid fermentation by oleaginous yeast using glucose and sonicated waste cooking oil. Ultrasonics sonochemistry, 52, 364-374
Open this publication in new window or tab >>A comparative study on de novo and ex novo lipid fermentation by oleaginous yeast using glucose and sonicated waste cooking oil
2019 (English)In: Ultrasonics sonochemistry, ISSN 1350-4177, E-ISSN 1873-2828, Vol. 52, p. 364-374Article in journal (Refereed) Published
Abstract [en]

There are only a few reports available about the assimilation of hydrophobic substrates by microorganisms, however, it is well known that oleaginous microorganisms are capable of utilizing both hydrophilic and hydrophobic substrates and accumulate lipids via two different pathways namely de novo and ex novo lipid synthesis, respectively. In the present study, an oleaginous yeast, Cryptococcus curvatus, was investigated for its potentials to utilize a waste substrate of hydrophobic nature (waste cooking oil – WCO) and compared with its ability to utilize a hydrophilic carbon source (glucose). To facilitate the utilization of WCO by C. curvatus, the broth was sonicated to form a stable oil-in-water emulsion without adding any emulsifier, which was then compared with WCO samples without any ultrasound treatment (unsonicated) for the yeast cultivation. Ultrasonication reduces the size of hydrophobic substrates and improves their miscibility in an aqueous broth making them easily assimilated by oleaginous yeast. Under de novo lipid fermentation, the yeast synthesized 9.93 ± 0.84 g/L of cell dry weight and 5.23 ± 0.49 g/L lipids (lipid content of 52.66 ± 0.93% w/w) when cultivated on 40 g/L of glucose (C/N ratio of 40). The amount of cell dry weight, lipid concentration, and lipid content were considerably higher during the ex novo lipid synthesis. More specifically, the highest lipid content achieved was 70.13 ± 1.65% w/w with a corresponding dry cell weight and lipid concentration of 18.62 ± 0.76 g/L and 13.06 ± 0.92 g/L respectively, when grown on 20 g/L sonicated WCO. The highest lipid concentration, however, was observed when the yeast was cultivated on 40 g/L sonicated WCO. Under these conditions, 20.34 g/L lipids were produced with a lipid content of 57.05% w/w. On the other hand, lipid production with unsonicated WCO was significant lower, reaching 11.16 ± 1.02 g/L (69.14 ± 1.34% w/w of lipid content) and 12.21 ± 1.34 g/L (47.39 ± 1.67% w/w of lipid content) for 20 g/L and 40 g/L of WCO, respectively. This underpins the significance of the sonication treatment, especially at elevated WCO concentrations, to improve the accessibility of the yeast to the WCO. Sonication treatment that was used in this study assisted the utilization of WCO without the need to add emulsifiers, thus reducing the need for chemicals and in turn has a positive impact on the production costs. The microbial lipids produced presented a different fatty acid composition compared to the WCO, making them more suitable for biodiesel production as suggested by the theoretical estimation of the biodiesel properties.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Oleaginous yeast, Sonicated waste cooking oil, De novo lipid accumulation, Ex novo lipid accumulation, LipidsFatty acid methyl esters
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-72671 (URN)10.1016/j.ultsonch.2018.12.010 (DOI)000467509200041 ()2-s2.0-85058415972 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-27 (oliekm)

Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2019-08-19Bibliographically approved
Hruzova, K., Patel, A., Masák, J., Maťátková, O., Rova, U., Christakopoulos, P. & Matsakas, L. (2019). A novel approach for the production of green biosurfactant from Pseudomonas aeruginosa using renewable forest biomass. Science of the Total Environment
Open this publication in new window or tab >>A novel approach for the production of green biosurfactant from Pseudomonas aeruginosa using renewable forest biomass
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2019 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026Article in journal (Refereed) Epub ahead of print
Abstract [en]

The rising demand for surfactants by the pharmaceuticals and cosmetic industries has generated vast amounts of petroleum-based synthetic surfactants, which are often toxic and non-degradable. Owing to their low toxicity, stability in extreme conditions, and biodegradability, biosurfactants could represent a sustainable alternative. The present study aimed to maximize the production of rhamnolipids (RL) from Pseudomonas aeruginosa by optimizing glucose concentration, temperature, and C/N and C/P ratios. After 96 h of cultivation at 37 °C, the final RL concentration was 4.18 ± 0.19 g/L with a final yield of 0.214 ± 0.010 g/gglucose when pure glucose was used as a carbon source. At present, the main obstacle towards commercialization of RL production is economic sustainability, due to the high cost of downstream processes and media components. For this reason, a renewable source such as wood hydrolysates (from birch and spruce woodchips) was examined here as a possible source of glucose for RL production. Both hydrolysates proved to be adequate, resulting in 2.34 ± 0.17 and 2.31 ± 0.10 g/L of RL, respectively, and corresponding yields of 0.081 ± 0.006 and 0.089 ± 0.004 g/gsugar after 96 h. These results demonstrate the potential of using renewable biomass for the production of biosurfactants and, to the best of our knowledge, they constitute the first report on the use of wood hydrolysates for RL production.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Rhamnolipid, Biosurfactants, Pseudomonas, Wood hydrolysate, Organosolv fractionation
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-76888 (URN)10.1016/j.scitotenv.2019.135099 (DOI)
Available from: 2019-11-27 Created: 2019-11-27 Last updated: 2019-11-27
Patel, A., Arora, N., Pruthi, V. & Pruthi, P. A. (2019). A novel rapid ultrasonication-microwave treatment for total lipid extraction from wet oleaginous yeast biomass for sustainable biodiesel production. Ultrasonics sonochemistry, 51, 504-516
Open this publication in new window or tab >>A novel rapid ultrasonication-microwave treatment for total lipid extraction from wet oleaginous yeast biomass for sustainable biodiesel production
2019 (English)In: Ultrasonics sonochemistry, ISSN 1350-4177, E-ISSN 1873-2828, Vol. 51, p. 504-516Article in journal (Refereed) Published
Abstract [en]

Oleaginous yeasts have emerged as a sustainable source of renewable oils for liquid biofuels. However, biodiesel production from them has few constraints with respect to their cell disruption and lipid extraction techniques. The lipid extraction from oleaginous yeasts commonly includes dewatering and drying of cell biomass, which requires energy and time. The aim of this work was to establish a process for the lipid extraction techniques from wet biomass applying acid catalyzed hot water, microwave, rapid ultrasonication-microwave treatment together with conventional Bligh and Dyer method. In the wake of testing all procedures, it was revealed that rapid ultrasonication-microwave treatment has great potential to give high lipid content (70.86 % w/w) on the cell dry weight basis. The lipid profile after treatment showed the presence of appropriate quantities of saturated (10.39 ± 0.15%), monounsaturated (76.55 ± 0.19%) and polyunsaturated fatty acids (11.49 ± 0.23%) which further improves biodiesel quality compared to the rest of methods. To the best of our knowledge, this is the first report of using rapid ultrasonication-microwave treatment for the lipid extraction from wet oleaginous yeast biomass in the literature.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-68648 (URN)10.1016/j.ultsonch.2018.05.002 (DOI)000454375900059 ()30082251 (PubMedID)2-s2.0-85049490275 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-12-05 (svasva)

Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2019-01-29Bibliographically approved
Patel, A., Matsakas, L., Rova, U. & Christakopoulos, P. (2019). A perspective on biotechnological applications of thermophilic microalgae and cyanobacteria. Bioresource Technology, 278, 424-434
Open this publication in new window or tab >>A perspective on biotechnological applications of thermophilic microalgae and cyanobacteria
2019 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 278, p. 424-434Article in journal (Refereed) Published
Abstract [en]

The importance of expanding our knowledge on microorganisms derived from extreme environments stems from the development of novel and sustainable technologies for our health, food, and environment. Microalgae and cyanobacteria represent a group of diverse microorganisms that inhabit a wide range of environments, are capable of oxygenic photosynthesis, and form a thick microbial mat even at extreme environments. Studies of thermophilic microorganisms have shown a considerable biotechnological potential due to their optimum growth and metabolisms at high temperatures (≥50 °C), which is supported by their thermostable enzymes. Microalgal and cyanobacterial communities present in high-temperature ecosystems account for a large part of the total ecosystem biomass and productivity, and can be exploited to generate several value-added products of agricultural, pharmaceutical, nutraceutical, and industrial relevance. This review provides an overview on the current status of biotechnological applications of thermophilic microalgae and cyanobacteria, with an outlook on the challenges and future prospects.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Thermophilic microorganisms, Microalgae, Cyanobacteria, Biotechnological applications, Biofuels, Biologically active compounds, Pigments
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-73043 (URN)10.1016/j.biortech.2019.01.063 (DOI)000457852400049 ()30685131 (PubMedID)2-s2.0-85060269950 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-27 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-02-27Bibliographically approved
Patel, A., Matsakas, L., Hruzova, K., Rova, U. & Christakopoulos, P. (2019). Biosynthesis of Nutraceutical Fatty Acids by the Oleaginous Marine Microalgae Phaeodactylum tricornutum Utilizing Hydrolysates from Organosolv-Pretreated Birch and Spruce Biomass. Marine Drugs, 17(12), Article ID 119.
Open this publication in new window or tab >>Biosynthesis of Nutraceutical Fatty Acids by the Oleaginous Marine Microalgae Phaeodactylum tricornutum Utilizing Hydrolysates from Organosolv-Pretreated Birch and Spruce Biomass
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2019 (English)In: Marine Drugs, ISSN 1660-3397, E-ISSN 1660-3397, Vol. 17, no 12, article id 119Article in journal (Refereed) Published
Abstract [en]

Polyunsaturated fatty acids (PUFAs) are essential for human function, however they have to be provided through the diet. As their production from fish oil is environmentally unsustainable, there is demand for new sources of PUFAs. The aim of the present work was to establish the microalgal platform to produce nutraceutical-value PUFAs from forest biomass. To this end, the growth of Phaeodactylum tricornutum on birch and spruce hydrolysates was compared to autotrophic cultivation and glucose synthetic media. Total lipid generated by P. tricornutum grown mixotrophically on glucose, birch, and spruce hydrolysates was 1.21, 1.26, and 1.29 g/L, respectively. The highest eicosapentaenoic acid (EPA) production (256 mg/L) and productivity (19.69 mg/L/d) were observed on spruce hydrolysates. These values were considerably higher than those obtained from the cultivation without glucose (79.80 mg/L and 6.14 mg/L/d, respectively) and also from the photoautotrophic cultivation (26.86 mg/L and 2.44 mg/L/d, respectively). To the best of our knowledge, this is the first report describing the use of forest biomass as raw material for EPA and docosapentaenoic acid (DHA) production.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
polyunsaturated fatty acids, EPA, DHA, marine algae, Phaeodactylum tricornutum, forest biomass
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-73136 (URN)10.3390/md17020119 (DOI)000460795500047 ()30781416 (PubMedID)2-s2.0-85061857091 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-07 (johcin)

Available from: 2019-03-07 Created: 2019-03-07 Last updated: 2019-04-24Bibliographically approved
Patel, A., Pruthi, V. & Pruthi, P. A. (2019). Innovative screening approach for the identification of triacylglycerol accumulating oleaginous strains. Renewable energy, 135, 936-944
Open this publication in new window or tab >>Innovative screening approach for the identification of triacylglycerol accumulating oleaginous strains
2019 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 135, p. 936-944Article in journal (Refereed) Published
Abstract [en]

Currently, triacylglycerides (TAG) accumulation in the form of lipid droplets (LDs) in oleaginous microorganisms is of immense importance due to their ability to get transesterified into value-added products in the form of biodiesel. Hence, in order to search for oleaginous microorganisms having high lipid content among a wide range of samples from different niches, there is a compulsive need to develop simple, reliable and rapid methods for screening of TAG accumulating strains. Conventional methods require multistep processes for the isolation, cultivation, extraction and estimation of lipids to identify oleagenic strains. To overcome these challenges, we are proposing an easy, live cellimaging technique for the estimation of lipids via visualization of TAG accumulation in probable strains at the single cell level that gives real-time monitoring of intracellular lipid accumulation in yeasts. In this screening technique, only 100 μl of specific neutral lipid accumulating medium was used to grow the isolated culture in the microtiter plate. The harvested cells were stained with LipidTOX™ Green and visualized by a LED based digital inverted fluorescence microscope. Among 446 yeast colonies screened, maximum lipid producing yeast strains Rhodosporidium kratochvilovae HIMPA1 and Rhodotorula minuta,having supersized lipid body of 5.05 ± 0.87 μm and 4.46 ± 0.61 μm, respectively, were identified as potential candidates for biodiesel production. To the best of our knowledge, this is the first report of using LipidTOX™ Green for the staining of lipid droplets present in yeast cells as per the literature.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Oleaginous microorganisms, Live fluorescence microscopy, Triacylglycerides (TAG), Lipid droplets (LDs), LipidTOX™ green, Biodiesel
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-72819 (URN)10.1016/j.renene.2018.12.078 (DOI)000459365600081 ()2-s2.0-85059591548 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-07 (johcin)

Available from: 2019-02-07 Created: 2019-02-07 Last updated: 2019-03-08Bibliographically approved
Patel, A., Antonopoulou, I., Enman, J., Rova, U., Christakopoulos, P. & Matsakas, L. (2019). Lipids detection and quantification in oleaginous microorganisms: an overview of the current state of the art. BMC Chemical Engineering, 1, Article ID 13.
Open this publication in new window or tab >>Lipids detection and quantification in oleaginous microorganisms: an overview of the current state of the art
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2019 (English)In: BMC Chemical Engineering, ISSN 2524-4175, Vol. 1, article id 13Article in journal (Refereed) Published
Abstract [en]

Oleaginous microorganisms are among the most promising feedstocks for the production of lipids for biofuels and oleochemicals. Lipids are synthesized in intracellular compartments in the form of lipid droplets. Therefore, their qualitative and quantitative analysis requires an initial pretreatment step that allows their extraction. Lipid extraction techniques vary with the type of microorganism but, in general, the presence of an outer membrane or cell wall limits their recovery. This review discusses the various types of oleaginous microorganisms, their lipid accumulating capabilities, lipid extraction techniques, and the pretreatment of cellular biomass for enhanced lipid recovery. Conventional methods for lipid quantification include gravimetric and chromatographic approaches; whereas non-conventional methods are based on infrared, Raman, nuclear magnetic resonance, and fluorescence spectroscopic analysis. Recent advances in these methods, their limitations, and fields of application are discussed, with the aim of providing a guide for selecting the best method or combination of methods for lipid quantification.

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Oleaginous microorganisms, Microbial lipids, Lipid extraction, Lipid quantification, Conventional methods, High-throughput analysis
National Category
Chemical Process Engineering Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-75376 (URN)10.1186/s42480-019-0013-9 (DOI)
Available from: 2019-07-30 Created: 2019-07-30 Last updated: 2019-08-14Bibliographically approved
Patel, A., Rova, U., Christakopoulos, P. & Matsakas, L. (2019). Simultaneous production of DHA and squalene from Aurantiochytrium sp. grown on forest biomass hydrolysates. Biotechnology for Biofuels, 12(1), Article ID 255.
Open this publication in new window or tab >>Simultaneous production of DHA and squalene from Aurantiochytrium sp. grown on forest biomass hydrolysates
2019 (English)In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 12, no 1, article id 255Article in journal (Refereed) Published
Abstract [en]

Background

Recent evidence points to the nutritional importance of docosahexaenoic acid (DHA) in the human diet. Thraustochytrids are heterotrophic marine oleaginous microorganisms capable of synthesizing high amounts of DHA, as well as other nutraceutical compounds such as squalene, in their cellular compartment. Squalene is a natural triterpene and an important biosynthetic precursor to all human steroids. It has a wide range of applications in the cosmetic and pharmaceutical industries, with benefits that include boosting immunity and antioxidant activity. Apart from its nutritional quality, it can also be utilized for high-grade bio-jet fuel by catalytic conversion.

Results

In the present study, the potential of thraustochytrid strain Aurantiochytrium sp. T66 to produce DHA and squalene was evaluated. When the strain was cultivated on organosolv-pretreated birch hydrolysate (30 g/L glucose) in flask, it resulted in 10.39 g/L of cell dry weight and 4.98 g/L of total lipids, of which 25.98% was DHA. In contrast, when the strain was grown in a bioreactor, cell dry weight, total lipid, and DHA increased to 11.24 g/L, 5.90 g/L, and 35.76%, respectively. The maximum squalene yield was 69.31 mg/gCDW (0.72 g/L) when the strain was cultivated in flask, but it increased to 88.47 mg/gCDW (1.0 g/L), when cultivation shifted to a bioreactor.

Conclusions

This is the first report demonstrating the utilization of low cost non-edible lignocellulosic feedstock to cultivate the marine oleaginous microorganism Aurantiochytrium sp. for the production of nutraceutical vital compounds. Owing to the simultaneous generation of DHA and squalene, the strain is suitable for industrial-scale production of nutraceuticals.

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Thraustochytrids, Aurantiochytrium sp., DHA, Squalene, Wood biomass, Organosolv pretreatment, Heterotrophic growth, Lipid production
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-76775 (URN)10.1186/s13068-019-1593-6 (DOI)31687043 (PubMedID)2-s2.0-85074448972 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-11-20 (johcin)

Available from: 2019-11-20 Created: 2019-11-20 Last updated: 2019-11-20Bibliographically approved
Patel, A., Hruzova, K., Rova, U., Christakopoulos, P. & Matsakas, L. (2019). Sustainable biorefinery concept for biofuel production through holistic volarization of food waste. Bioresource Technology, 294, Article ID 122247.
Open this publication in new window or tab >>Sustainable biorefinery concept for biofuel production through holistic volarization of food waste
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2019 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 294, article id 122247Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to utilize the whole food waste in two stages. In the first stage, the carbohydrate and protein fractions of food waste recovered after enzymatic hydrolysis was used to cultivate heterotrophic microalgae, resulting in biomass yield of 0.346 ± 0.09 g/gsugars and lipid yield of 0.216 ± 0.06 g/gsugars. In the second stage, oil (14.15% w/w) was extracted from food waste after hydrolysis and converted to biodiesel by a two-step transesterification reaction that generated 135.8 g/kgfood waste of fatty acid methyl esters and 13.8 g/kgfood waste of crude glycerol. Finally, crude glycerol obtained from both processes was used at 20 g/L to cultivate heterotrophic microalgae, resulting in a cell dry weight and total lipid concentration of 6.23 g/L and 2.91 g/L, respectively. A total 248.21 g of fatty acid methyl esters were obtained from the 1 kg of food waste through this integrated process.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Food waste, Enzymatic hydrolysis, Microalgae, Heterotrophic cultivation, Lipids, Fatty acid methyl esters
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-76458 (URN)10.1016/j.biortech.2019.122247 (DOI)000492696100060 ()31683456 (PubMedID)2-s2.0-85073202083 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-21 (johcin)

Available from: 2019-10-21 Created: 2019-10-21 Last updated: 2019-12-09Bibliographically approved
Patel, A., Sartaj, K., Pruthi, P., Pruthi, V. & Matsakas, L. (2019). Utilization of Clarified Butter Sediment Waste as a Feedstock for Cost-Effective Production of Biodiesel. Foods, 8(7), Article ID 234.
Open this publication in new window or tab >>Utilization of Clarified Butter Sediment Waste as a Feedstock for Cost-Effective Production of Biodiesel
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2019 (English)In: Foods, E-ISSN 2304-8158, Vol. 8, no 7, article id 234Article in journal (Refereed) Published
Abstract [en]

The rising demand and cost of fossil fuels (diesel and gasoline), together with the need for sustainable, alternative, and renewable energy sources have increased the interest for biomass-based fuels such as biodiesel. Among renewable sources of biofuels, biodiesel is particularly attractive as it can be used in conventional diesel engines without any modification. Oleaginous yeasts are excellent oil producers that can grow easily on various types of hydrophilic and hydrophobic waste streams that are used as feedstock for single cell oils and subsequently biodiesel production. In this study, cultivation of Rhodosporidium kratochvilovae on a hydrophobic waste (clarified butter sediment waste medium (CBM)) resulted in considerably high lipid accumulation (70.74% w/w). Maximum cell dry weight and total lipid production were 15.52 g/L and 10.98 g/L, respectively, following cultivation in CBM for 144 h. Neutral lipids were found to accumulate in the lipid bodies of cells, as visualized by BODIPY staining and fluorescence microscopy. Cells grown in CBM showed large and dispersed lipid droplets in the intracellular compartment. The fatty acid profile of biodiesel obtained after transesterification was analyzed by gas chromatography-mass spectrometry (GC–MS), while its quality was determined to comply with ASTM 6751 and EN 14214 international standards. Hence, clarified sediment waste can be exploited as a cost-effective renewable feedstock for biodiesel production. 

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
clarified butter sediment waste, hydrophobic substrates, oleaginous yeast, lipids, biodiesel, fatty acid methyl esters
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-75277 (URN)10.3390/foods8070234 (DOI)000481473600021 ()31261933 (PubMedID)2-s2.0-85069216259 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-10 (johcin)

Available from: 2019-07-10 Created: 2019-07-10 Last updated: 2019-09-09Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-5285-1136

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