Enhancement Of Lipid Production In Trichosporon Fermentans By The Nutrients-limitation Strategies

Production of microbial lipid from cheap raw materials such as Jerusalem artichoke,industrial and agricultural waste is a hotspot research in recent years.Corrently,nitrogen limition is the main way to promote microbial lipid accumulation.However,the coupling of carbon source and nitrogen source in natural ingredients hindered for its large-scale application.In this paper,we achieved a higher yield of lipid accumulation by phosphate limitation and sulfate limitation environments and two-stage cultivation strategy,and conducted a preliminary application in natural material Jerusalem artichoke.(1)Trichosporon fermentans CICC 1368 fermnetation for lipids production using fructose-the monomer of Jerusalem artichoke-as carbon scource is investigated under high C/N ratios and different phosphorus concentration gradients.The results indicate that phosphorus limitation can effectively control the accumulation of lipid,which is consistent with the imaging analysis and low-field NMR analysis.TLC and GC analysis shows that C/P ratio had little effect on the composition of lipid oil and fatty acid.The lipid concentration reached 6.8 g/L and the lipid content rose to 44% at a C/P molar ratio of 6342.(2)The oil production was improved by two-stage cultivation strategy and Fungus age optimization experiment.Results showed that in a two-stage culture mode,the lipid concentration reached 8.3 g/L and the lipid content rose to 49.6%,which is respectively 3.2 times and 4.7 times of one-stage results.Biomass,lipid and lipid content were also higher than that of one-stage.The older fungus age,the greater improvement of the lipid product efficiency,and the optimal fungus age was 36 h(3)Trichosporon fermentans CICC 1368 fermnetation for lipids production using fructose as carbon scource is investigated under high C/N ratios and different phosphorus concentration gradients.The results indicated that sulfur limitation can effectively control the accumulation of lipid,which is consistent with the imaging analysis and low-field NMR analysis.TLC and GC analysis shows that C/S ratio had little effect on the composition of lipid oil and fatty acid.The lipid concentration reached 8.9 g/L and the lipid content rose to 45% at a C/S molar ratio of 3310.(4)The dual limitation of nutrition and two-stage cultivation were simultaneously investigated in the fermnetation of natural inulin hydrolysate under high C/N ratios.Results showed that the limitation of nutrition is conducive to the accumulation of lipid,while the two-stage cultivation shows little effect.