Enhanced Ethanol Production from Sugarcane Bagasse Hydrolysate with High Content of Inhibitors by an Adapted Barnettozyma Californica

Bioethanol production from acid hydrolysate of sugarcane bagasse's hemicellulose was studied using an adapted new yeast strain, Barnettozyma californica HNMA-5. The growth rate and ethanol production were studied by using the adapted and the parental strains in Sugarcane Bagasse Hydrolysate (SBH) and Concentrated Sugarcane Bagasse Hydrolysate (CSBH). The hydrolysate concentration resulted in an increase of total sugar from 34 to 51.8 g L-1 and an approximately twofold increase in nonvolatile toxic compounds like phenol (1.017-2.11 g L-1) in CSBH. An adaptation of the yeast strain to CSBH resulted in improved growth ability and ethanol production, whereas no significant effect was observed in SBH. The adapted yeast showed a promising ethanol production of 4.804 g L-1 after 24 h compared to the parental strain, which produced 1.233 g L-1 after 72 h of fermentation. The adapted yeast could produce about four times more ethanol than the parental strain. In addition, the lag phase decreased from 9 to 5 h and productivity increased 10-fold. Furthermore, the hydrolysate concentration and the yeast's adaptation were effective methods to improve ethanol production in CSBH. Our data indicate that the new yeast isolate, B. californica HNMA-5 could be successfully applied to lignocellulosic ethanol production. (C) 2017 American Institute of Chemical Engineers