Simultaneous fermentation of glucose and xylose by using co-culture of S. cerevisiae and a potential robust pentose fermenting fungi (Fusarium incarnatum)

Xylose is the second most prevalent sugar in lignocellulosic biomass after glucose. However, most of the microbial strains are unable to metabolize xylose efficiently leading to reduced ethanol yield and poor volumetric productivity. The aim of the study was to develop a co-culture strategy for efficient production of ethanol from mustard biomass. Present study covers enzymatic hydrolysis of alkali-treated mustard biomass using mixture of different cellulases. The highest reducing sugar (500.06 mg/g dry substrate) was obtained at a substrate loading of 15% (w/v), pH 5 within 48 h of incubation. Pentose sugar fermenting Fusarium incarnatum MTCC 10,292 was characterized for assimilation of different sugars and tolerance to ethanol and acetic acids. Optimization of simultaneous saccharification and fermentation process using co-culture of Fusarium incarnatum MTCC 10,292 and Saccharomyces cerevisiae MTCC 170 was carried out by using variable parameters. Within 5 days of incubation, the maximum ethanol production (3.29%, w/v) was recorded. Significant utilization of both hexose and pentose sugars for ethanol production is the major challenge for commercial lignocellulosic bioethanol production. This problem has been addressed in this study through co-culture strategy.