Abstracto

The effect of furfural compounds in corn cob hydrolysate on microbial lipid accumulation of Trichosporon cutaneum for biomass bioprocessing to oil.

Hongfei Yu, Liuyang Wang, Lijun Guo, Yiming Chen, Wensheng Qin and Yun Liu

The oleaginous yeast Trichosporon cutaneum is an ideal strain to produce microbial lipids by fermentation in corncob hydrolysate. However, furfural, routinely generated during lignocellulose hydrolysis, shows detrimental effects on microbial lipid accumulation , the mechanism of which has not been well marked so far. In this paper, corncob biomass was hydrolyzed with 0.12 M diluted H ₂ SO ₄ and directly used as fermentation medium of T. cutaneum . The different initial furfural content was obtained by adding the proportional amount of furfural to the detoxified corncob hydrolysates. To explore the furfural-mediated mechanism of microbial lipid accumulation in this work, atomic force microscopy was used to visualize the morphological features and high-performance liquid chromatograph was employed to evaluate the furfural metabolism of yeast during the detrimental process of furfural. Furthermore, flow cytometry was used to monitor the growth of yeast and images were obtained by fluorescence spectroscopy in the dynamic process of microbial lipid accumulation. The analysis reveals that furfural at a low concentration (≤0.4 g/L) can be metabolized by yeast into 2-furoic acid with little detrimental effect on microbial lipid accumulation. The mechanism of furfural detriment related to cytomembrane damage to prevent yeast cell growth is proposed as the main cause of the lack of microbial lipid accumulation of T. cutaneum under high furfural concentration situations (≥ 0.6 g/L). These results provide valuable information to develop and design a more efficient biomass-to-lipid fermentation bioprocess.