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| 2. |
- Blomqvist, Johanna, et al.
(author)
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Oleaginous yeast as a component in fish feed
- 2018
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Journal article (peer-reviewed)abstract
- This study investigates the replacement of vegetable oil (VO) in aquaculture feed for Arctic char (Salvelinus alpinus) with oil produced by the oleaginous yeast Lipomyces starkeyi grown in lignocellulose (wheat straw) hydrolysate. VO is extensively used to partially replace fish oil in aquaculture feed, which can be seen as non-sustainable. VO itself is becoming a limited resource. Plant oils are used in many different applications, including food, feed and biodiesel. Its replacement in non-food applications is desirable. For this purpose, yeast cells containing 43% lipids per g dry weight were mechanically disrupted and incorporated into the fish feed. There were no significant differences in this pilot study, regarding weight and length gain, feed conversion ratio, specific growth rate, condition factor and hepatosomatic index between the control and the yeast oil fed group. Fatty and amino acid composition of diet from both groups was comparable. Our results in fish demonstrate that it is possible to replace VO by yeast oil produced from lignocellulose, which may broaden the range of raw materials for food production and add value to residual products of agriculture and forestry.
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| 3. |
- Brandenburg, Jule, et al.
(author)
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Oleaginous yeasts respond differently to carbon sources present in lignocellulose hydrolysate
- 2021
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In: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14
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Journal article (peer-reviewed)abstract
- Background Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By unravelling the diversity of lipid accumulation physiology in different oleaginous yeasts grown on the various carbon sources present in lignocellulose hydrolysate (LH), new targets for optimisation of lipid accumulation can be identified. Monitoring lipid formation over time is essential for understanding lipid accumulation physiology. This study investigated lipid accumulation in a variety of oleaginous ascomycetous and basidiomycetous strains grown in glucose and xylose and followed lipid formation kinetics of selected strains in wheat straw hydrolysate (WSH). Results Twenty-nine oleaginous yeast strains were tested for their ability to utilise glucose and xylose, the main sugars present in WSH. Evaluation of sugar consumption and lipid accumulation revealed marked differences in xylose utilisation capacity between the yeast strains, even between those belonging to the same species. Five different promising strains, belonging to the species Lipomyces starkeyi, Rhodotorula glutinis, Rhodotorula babjevae and Rhodotorula toruloides, were grown on undiluted wheat straw hydrolysate and lipid accumulation was followed over time, using Fourier transform-infrared (FTIR) spectroscopy. All five strains were able to grow on undiluted WSH and to accumulate lipids, but to different extents and with different productivities. R. babjevae DVBPG 8058 was the best-performing strain, accumulating 64.8% of cell dry weight (CDW) as lipids. It reached a culture density of 28 g/L CDW in batch cultivation, resulting in a lipid content of 18.1 g/L and yield of 0.24 g lipids per g carbon source. This strain formed lipids from the major carbon sources in hydrolysate, glucose, acetate and xylose. R. glutinis CBS 2367 also consumed these carbon sources, but when assimilating xylose it consumed intracellular lipids simultaneously. Rhodotorula strains contained a higher proportion of polyunsaturated fatty acids than the two tested Lipomyces starkeyi strains. Conclusions There is considerable metabolic diversity among oleaginous yeasts, even between closely related species and strains, especially when converting xylose to biomass and lipids. Monitoring the kinetics of lipid accumulation and identifying the molecular basis of this diversity are keys to selecting suitable strains for high lipid production from lignocellulose.
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| 4. |
- Brunel, Mathilde, et al.
(author)
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Oleaginous yeast Rhodotorula toruloides biomass effect on the metabolism of Arctic char (Salvelinus alpinus)
- 2022
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In: Frontiers in Molecular Biosciences. - : Frontiers Media SA. - 2296-889X. ; 9
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Journal article (peer-reviewed)abstract
- Sustainability issues arise when using fish oil and vegetable oils in fish feed production for aquaculture purposes. Microbial production of single cell oil is a potential alternative as a lipid ingredient in the production of fish feed. In this study, we replaced the vegetable oils with the oleaginous yeast R. toruloides biomass in the diet of Arctic char (S. alpinus) and investigated the effects on health and composition. Measurement of fish growth parameters showed a higher liver weight and hepatosomatic index in the experimental group of fish fed partly with yeast biomass compared to a control group fed a diet with vegetable oils. No significant differences in the lipid content of muscle and liver tissues were found. The fatty acid profiles in the muscle of both fish groups were similar while the experimental fish group had a higher amount of monounsaturated fatty acids in the liver. Histology of livers showed no significant difference in the number of lipid droplets. The size of hepatic lipid droplets seemed to be related to liver fat content. Quantification of metabolites in the liver revealed no differences between the fish groups while plasma metabolites involved in energy pathways such as alanine, 3-hydroxybutyrate, creatinine, serine, betaine, and choline were significantly higher in the experimental fish group.
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| 5. |
- Cerveny, Daniel, et al.
(author)
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Insect Meal as a Partial Replacement for Fish Meal in a Formulated Diet for Perch Perca fluviatilis
- 2020
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In: Turkish Journal Of Fisheries And Aquatic Sciences. - : Central Fisheries Research Institute (SUMAE). - 1303-2712. ; 20, s. 867-878
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Journal article (peer-reviewed)abstract
- The growing importance of aquaculture products for human health also raises the question of product sustainability and decreasing its costs. Insects are considered as novel feed ingredients and source of proteins. In this study, a twelve-week feeding trial with replacement of 25% fishmeal by a mixture of house cricket (Acheta domesticus) and superworm (Zophobas morio) in the fish feed was conducted with perch (Perca fluviatilis). There were no significant differences in this feeding trial, regarding survival, but decreased fish growth and increased feed conversion between the control and the experimental fed groups. Hepatic cytochrome P450 (CYP1A and CYP3A-like) activity and fatty acid (FA) composition were assessed in perch also. No significant effects were observed on cytochrome P450 activity associated with presence of toxic compounds in fish. Feeding with insect pellets resulted in significant increasing of linoleic FA and an increase of the total content of n-6 FA in fish fillets, compared to the fish fillets from control group. However, changes in FA composition were only minor and did not affect the nutritional value of the fish with insect-based diet for human consumption. Further evaluation should be conducted with different ratios or different insect species.
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| 6. |
- Chmielarz, Mikolaj, et al.
(author)
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FT-NIR: a tool for rapid intracellular lipid quantification in oleaginous yeasts
- 2019
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In: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 12
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Journal article (peer-reviewed)abstract
- BackgroundLipid extraction for quantification of fat content in oleaginous yeasts often requires strong acids and harmful organic solvents; it is laborious and time-consuming. Therefore, in most cases just endpoint measurements of lipid accumulation are performed and kinetics of intracellular lipid accumulation is difficult to follow. To address this, we created a prediction model using Fourier-transform near-infrared (FT-NIR) spectroscopy. This method allows to measure lipid content in yeast.MethodsThe FT-NIR calibration sets were constructed from spectra of freeze-dried cells of the oleaginous yeasts Rhodotorula toruloides CBS 14, Lipomyces starkeyi CBS 1807 and Yarrowia lipolytica CBS 6114. The yeast cells were obtained from different cultivation conditions. Freeze-dried cell pellets were scanned using FT-NIR in the Multi Purpose Analyser (MPA) from Bruker. The obtained spectra were assigned corresponding to total fat content, obtained from lipid extraction using a modified Folch method. Quantification models using partial least squares (PLS) regression were built, and the calibration sets were validated on independently cultivated samples. The R. toruloides model was additionally tested on Rhodotorula babjevae DBVPG 8058 and Rhodotorula glutinis CBS 2387.ResultsThe R-2 of the FT-NIR model for R. toruloides was 98%, and the root mean square error of cross-validation (RMSECV) was 1.53. The model was validated using a separate set of R. toruloides samples with a root mean square error of prediction (RMSEP) of 3.21. The R-2 of the Lipomyces model was 96%, with RMSECV 2.4 and RMSEP 3.8. The R-2 of the mixed model, including all tested yeast strains, was 90.5%, with RMSECV 2.76 and RMSEP 3.22, respectively. The models were verified by predicting the total fat content in newly cultivated and freeze-dried samples. Additionally, the kinetics of lipid accumulation of a culture were followed and compared with standard lipid extraction methods.ConclusionsUsing FT-NIR spectroscopy, we have developed a faster, less laborious and non-destructive quantification of yeast intracellular lipid content compared to methods using lipid extraction.
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| 7. |
- Chmielarz, Mikolaj, et al.
(author)
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Microbial lipid production from crude glycerol and hemicellulosic hydrolysate with oleaginous yeasts
- 2021
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In: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14
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Journal article (peer-reviewed)abstract
- Background Crude glycerol (CG) and hemicellulose hydrolysate (HH) are low-value side-products of biodiesel transesterification and pulp-and paper industry or lignocellulosic ethanol production, respectively, which can be converted to microbial lipids by oleaginous yeasts. This study aimed to test the ability of oleaginous yeasts to utilise CG and HH and mixtures of them as carbon source. Results Eleven out of 27 tested strains of oleaginous yeast species were able to grow in plate tests on CG as sole carbon source. Among them, only one ascomycetous strain, belonging to Lipomyces starkeyi, was identified, the other 10 strains were Rhodotorula spec. When yeasts were cultivated in mixed CG/ HH medium, we observed an activation of glycerol conversion in the Rhodotorula strains, but not in L. starkeyi. Two strains-Rhodotorula toruloides CBS 14 and Rhodotorula glutinis CBS 3044 were further tested in controlled fermentations in bioreactors in different mixtures of CG and HH. The highest measured average biomass and lipid concentration were achieved with R. toruloides in 10% HH medium mixed with 55 g/L CG-19.4 g/L and 10.6 g/L, respectively, with a lipid yield of 0.25 g lipids per consumed g of carbon source. Fatty acid composition was similar to other R. toruloides strains and comparable to that of vegetable oils. Conclusions There were big strain differences in the ability to convert CG to lipids, as only few of the tested strains were able to grow. Lipid production rates and yields showed that mixing GC and HH have a stimulating effect on lipid accumulation in R. toruloides and R. glutinis resulting in shortened fermentation time to reach maximum lipid concentration, which provides a new perspective on converting these low-value compounds to microbial lipids.
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| 8. |
- Ewald, Nils, et al.
(author)
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Fatty acid composition of black soldier fly larvae (Hermetia illucens) - Possibilities and limitations for modification through diet
- 2020
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In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 102, s. 40-47
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Journal article (peer-reviewed)abstract
- Black soldier fly larvae (Hermetia illucens; BSFL) can convert organic wastes into a nutrient-rich biomass suitable in animal feed, which could be a way to achieve more sustainable production of food. However, little is known about how the diet fed to BSFL affects their nutritional value, especially their fatty acid composition. In this study, BSFL were fed 11 diets based on four different organic waste sources (mussels, bread, fish and food waste). Fatty acid and proximate composition (dry matter, crude fat, crude protein and ash) were analysed in the diets, in two-week-old larvae and substrate residues. Larval weight, survival and feed conversion were also recorded. The diet was found to affect all parameters investigated. Irrespective of diet, the larval fat consisted mainly of lauric acid and other saturated fatty acids and these were found to be synthesised by the larvae. However, both the fatty acid composition of the substrate, and the larval weight were found to affect the fatty acid profile of the larvae. In general, larvae with a higher weight contained a higher percentage of saturated fatty acids and a lower percentage of unsaturated fatty acids, such as eicosapentaenoic (EPA) and docosahexaenoic acid (DHA). It was concluded that the possibilities to tailor the fatty acid composition of the BSFL through the diet are limited; thus, the BSFL fat may not be suitable to replace fish oil, but has potential of inclusion in other food, feed and fuel products. (C) 2019 The Authors. Published by Elsevier Ltd.
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| 9. |
- Lindahl, Gunilla, et al.
(author)
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Ageing of large cuts of beef loin in vacuum or high oxygen modified atmosphere - Effect on shear force, calpain activity, desmin degradation and protein oxidation
- 2010
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In: Meat Science. - : Elsevier BV. - 0309-1740 .- 1873-4138. ; 85, s. 160-166
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Journal article (peer-reviewed)abstract
- The aim was to investigate the effect of ageing large beef cuts directly in high oxygen modified atmosphere (MA) and how ageing time in vacuum influence meat quality when followed by retail packaging in high oxygen MA. Large cuts (10 cm long) of beef loin (LD) were aged for up to 25 days postmortem in different ageing systems at 4 degrees C. Ageing solely in high oxygen modified atmosphere (MA, 80% O(2) + 20% CO(2)) for 5 or 10 days and ageing in vacuum for 5 or 15 days followed by high oxygen MA for 5 or 10 days were compared with ageing in vacuum for 5, 15 and 25 days. Warner-Bratzler shear force, purge and cooking losses, calpain activity and desmin and carbonyl contents were measured. Shear force decreased to the same level when ageing this large beef cut solely in high oxygen MA for 5 or 10 days as when ageing in vacuum. The activity of mu-calpain disappeared, the activity of m-calpain decreased and purge loss increased between 5 and 10 days, but cooking loss and the contents of desmin and carbonyls were unaffected. The ageing time in vacuum before packaging of this large beef cut in high oxygen MA did not affect the ultimate shear force. The m-calpain activity decreased and the content of carbonyls increased compared with solely in vacuum after 15 days of total ageing, but there was no difference in the content of desmin or cooking loss between these ageing systems at the same ageing time. (C) 2009 Elsevier Ltd. All rights reserved.
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| 10. |
- Lu, Jing, et al.
(author)
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Lipolysis and Oxidation in Ultra-High Temperature Milk Depend on Sampling Month, Storage Duration, and Temperature
- 2019
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In: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 84, s. 1045-1053
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Journal article (peer-reviewed)abstract
- During storage, some factors (for example, storage duration and temperature) can affect milk stability and consumer acceptability. Thiobarbituric acid reactive substances (TBARSs), lipid classes, and fatty acid profiles in stored ultra-high temperature (UHT) milk were analyzed to assess the effects of storage time and temperature on lipid oxidation and lipolysis. With storage duration up to 12 months, the milk fat phase was separated and showed high levels of oxidation and lipolysis, manifested as increased levels of TBARS and free fatty acids. High oxidation levels decreased the percentage of unsaturated fatty acids (UFAs) in triacylglycerol and phospholipids. Higher storage temperatures (20, 30, and 37 degrees C) resulted in a higher degree of fat aggregation, oxidation, and lipolysis compared with refrigerated storage (4 degrees C). Additionally, sampling month of raw milk (May, July, and November) affected the lipid profiles of UHT milk during storage, with more UFA oxidized in July than in the other 2 months.
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