Effect of photocatalytic pretreatment of potato starch for bioethanol production using Saccharomyces cerevisiae during simultaneous saccharification-fermentation (SSF)

Abstract

In this study, the effect of photocatalytic (PC) pretreatment of potato starch with TiO2 during the gelatinization (GE) stage of a simultaneous saccharification-fermentation (SSF) process for bioethanol production was evaluated. The maximum amounts of reducing sugars were 119.3, 114.6 and 104.8 g l-1 for PC→GE, GE→PC and the reference (without PC), respectively, while bioethanol concentration gradually increased to a maximum amount of 128.21, 106.74 and 85.91 g l-1 after 30 h for PC→GE, GE→PC and the reference (without PC), respectively. Although enzymatic activity (ʋmax) for each treatment was similar, in the reference (without PC pretreatment) it did not promote rapid substrate conversion into ethanol, despite showing the higher affinity enzyme-substrate (Km). Considering traditional potato starch hydrolysis, PC pretreatment shortened the reaction time of the biological reactions. Thus, the PC pretreatment of potato starch for bioethanol production could be an environmentally feasible process without the addition of acid and alkali.