Effect of carbon and nitrogen source concentrations on the growth and lipid accumulation of yeastTrichosporon oleaginosusin continuous and batch culture

Abstract

BACKGROUND Biodiesel is an alternative to conventional fossil diesel fuel. Currently, it is mainly produced from vegetable oils and consequently it has an adverse impact on food price. Lipids from oleaginous microorganisms (e.g. microalgae, bacteria, fungi and yeasts) could be an alternative feedstock for biodiesel production and therefore the growth and lipid accumulation of Trichosporon oleaginosus was studied under different conditions. RESULTS The growth of T. oleaginosus on the xylose containing media enhanced the lipid accumulation and reduced cell growth, while on the glucose‐containing media the opposite effect was observed. Trichosporon oleaginosus can accumulate above 50% of total lipids in dry cell mass during continuous and batch culture in the nitrogen‐limited conditions. In the continuous culture relatively high productivity of total lipid accumulation (0.67 g dm−3 h−1) was observed on the glucose containing media. The type of substrate limitation has considerable impact on the fatty acid composition of yeast cell lipids. The predicted biodiesel properties (based on the fatty acids composition of lipids) were found to meet the CEN quality standards. CONCLUSION The results obtained show that T. oleaginosus has great potential for feasible biodiesel production, especially when sugars from industrial and agricultural waste are used as a substrate. © 2016 Society of Chemical Industry

Strategies for Improvement of Lipid Production by Yeast Trichosporon oleaginosus from Lignocellulosic Biomass

“…Growth media contained phosphate buffer (50 mM, pH = 5.0), trace elements and nutrient solution. Macro and micronutrients were added to obtain the final concentrations: (trace elements solution) 40 [8]. Optimal initial carbon to nitrogen ratio of 207.4 mol mol −1 was obtained by supplementing growth media with the appropriate amount of NH 4 Cl.…”

“…The next two fed-batch SSF experiments were performed at a high enzyme loading of 30 FPU Cellic CTec2 per gram of glucan at two molar carbon to nitrogen ratios (C:N, mol mol −1 ) of 207.4 (FB_3) and 38.7 mol mol −1 (FB_4) [8]. Initial substrate loading in both cultivations was 7.5% (g g −1 ).…”

“…Yeast biomass was washed with water and freeze-dried. The lipid content in cell biomass was determined using a modified Schneiter and Daum extraction protocol [8,28,29].…”

“…The most abundant lipid class in cell biomass, neutral lipids (primarily triacylglycerols), are stored in the form of intracellular lipid bodies at levels exceeding 70% of dry cell mass under favourable growth conditions. The most dominant fatty acids in yeast lipids are myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), stearic acid C18:0), oleic acid (C18:1), and linoleic acid (C18:2) [8,9]. Since the fatty acid composition of microbial lipids is similar to that of vegetable oils, they can be readily used for the production of biodiesel.…”

“…Lipid content in cells grown on a glucose-based medium under nitrogen deprivation usually exceeds 50% of dry cell weight, while lipid productivity reaches maximal 0.67 g L −1 h −1 . Due to the favourable fatty acid profile, T. oleaginosus is considered as a promising strain for the production of microbial lipids and biodiesel [8].…”