Microbial lipid production as biodiesel feedstock from N-acetylglucosamine by oleaginous microorganisms

BACKGROUND: The byproducts from shrimp processing are heads and shells which contain a wealth of carbon and could be converted into oils via oleaginous microorganisms. The objective of this investigation was to determine the feasibility of using oleaginous microorganisms to convert N-acetylglucosamine (GlcNAc), the major carbohydrate of the hydrolysate of shrimp processing waste, to triacylglycerols as a biodiesel feedstock. RESULTS: Screening experiments were conducted among Rhodotorula glutinis, Rhodococcus opacus and Cryptococcus curvatus using GlcNAc as sole carbon and energy source at 30 degrees C. All three microorganisms were found to grow well on GlcNAc, but the lipid contents in the cells were consistently low (lower than 5%) in the growth phase. However, lipid accumulation by C. curvatus was greatly enhanced upon entering the death phase in the absence of GlcNAc and the lipid content increased to 28.4% at 167.7 h. This indicated that C. curvatus was the optimal tested microorganism for the production of microbial oils from GlcNAc. Phosphate was further evaluated on the growth and lipid production by C. curvatus from GlcNAc. Results indicated that the yields of both biomass during growth phase and lipids at death phase increased with the increase of the ratio of C to P. But the fatty acid profiles of the accumulated lipids did not change significantly. CONCLUSION: Results indicated that shrimp processing waste could be utilized to produce oils as a biodiesel feedstock. The results could be applied to maximize production of oils from shrimp processing waste. (C) 2011 Society of Chemical Industry