Repeated batch fermentation with water recycling and cell separation for microbial lipid production

Abstract

Large waste water disposal was the major problem in microbial lipid fermentation because of low yield of lipid. In this study, the repeated batch fermentation was investigated for reducing waste water generated in the lipid fermentation of an oleaginous yeast Trichosporon cutaneum CX1 strain. The waste fermentation broth was recycled in the next batch operation after the cells were separated using two different methods, centrifugation and flocculation. Two different sugar substrates, glucose and inulin, were applied to the proposed operation. The result showed that at least 70% of the waste water was reduced, while lipid production maintained satisfactory in the initial four cycles. Furthermore, it is suggested that T. cutaneum CX1 cells might produce certain naturally occurring inulin hydrolyzing enzyme(s) for obtaining fructose and glucose from inulin directly. Our method provided a practical option for reducing the waste water generated from microbial lipid fermentation.

Key words： batch fermentation; microbial lipid; Trichosporon cutaneum CX1; flocculation; waste water recycle

Acknowledgments

This research was supported by the National Basic Research Program of China (No. 2011CB707406), the National Natural Science Foundation of China (Grant No. 20976051), the Fundamental Research Funds for the Central Universities of China (WF0913005/1114054), and the Shanghai Leading Academic Discipline Project (B505).

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