ABSTRACT
The objective of this work is to investigate how dilution rate and carbon-to-nitrogen (C/N) ratio affects lipid accumulation by Rhodosporidium toruloides AS 2.138 9 in continuous culture. Under steady-state conditions, the increase in dilution rate led to the decrease in lipid content and lipid yield. The highest lipid yield and lipid content at D = 0.02 h(-1) were 0.18 g lipid/g sugar and 57.1%, respectively, while the highest lipid productivity and biomass productivity were obtained at D = 0.14 h(-1). The increase in C/N ratio led to the increase in lipid content. The highest lipid content of 38% was obtained at C/N = 237. The highest lipid yield of 0.12 g lipid/g sugar was obtained at C/N = 92. However, the highest lipid productivity of 0.12 g/(L x h) was obtained at C/N = 32. No significant changes were observed in terms of fatty acid composition of the lipid produced under different C/N ratios, and these three fatty acids, palmitic acid, stearic acid and oleic acid, took over 85% in all samples.
Subject(s)
Basidiomycota , Metabolism , Batch Cell Culture Techniques , Carbon , Metabolism , Culture Media , Fatty Acids , Metabolism , Glucose , Metabolism , Lipids , Nitrogen , Metabolism , Oleic Acid , Palmitic Acid , MetabolismABSTRACT
Microbial lipid is a potential raw material for biofuel industry. In this review, we summarized recent progress in microbial lipid production by oleaginous fungi in terms of identifying cheap feedstock, developing robust lipid producer, establishing novel strategies and better culture modes for cellular lipid accumulation, as well as revealing the molecular mechanism of oleaginity. We discussed issues, solutions and directions for further development of microbial lipid technology.
Subject(s)
Biofuels , Cellulose , Metabolism , Fatty Acids , Fermentation , Fungi , Cell Biology , Metabolism , Industrial Microbiology , Methods , LipidsABSTRACT
To shorten the cultivation time and reduce the consumption of raw materials for microbial lipid production, oleaginous yeast Rhodosporidium toruloides AS 2.1389 was cultivated using a two-stage culture mode, in which the cell propagation and lipid accumulation were separated. The yeast cells recovered from the propagation culture were re-suspended in glucose solution for lipid accumulation, through which lipid content over 55% of the dry cell weight was achieved, the longer the propagation stage was, the higher the lipid content. Analysis of the lipid indicated that the long-chain fatty acids with 16 and 18 carbon atoms were major components, suggesting that the lipid can be an alternative feedstock for biodiesel production.