Optimizing bioethanol production from cassava peels through agitation timing variation in separate hydrolysis and co-fermentation

Background: This study assessed the effect of various agitation timings on bioethanol production from cassava peels (CP) using separate hydrolysis and co-fermentation (SHCF) technique. Methods: The milled CP was divided into three groups each of ۲۰ g and subjected to two-stage hydrolysis carried out at ۱۰۰ oC for ۶۰ min and ۵۰ minutes, respectively. Experimental layouts were Sample ۱ (B۱) [۰ hours i.e., no shaking], Sample ۲ (B۲) [۳ hours shaking with an electric shaker at ۲۰۰ rev/min-۱], and Sample ۳ (B۳) [۶ hours shaking at ۲۰۰ rev/min-۱]. Fermentations were carried out at ۳۰ oC for ۷۲ days. Data were analyzed using descriptive statistics, one–way ANOVA, and New Duncan’s multiple range test at P = ۰.۰۵. Results: The TSS and pH readings of the treatment groups before and after fermentation were: B۱ – TSS (۲۷.۱۵ ± ۰.۱۵, ۱۷.۲۵ ± ۰.۰۷ oBx), pH (۵.۵۰ ± ۰.۰۰, ۴.۵۳ ± ۰.۰۴); B۲ – TSS (۲۷.۳۲ ± ۰.۰۸, ۱۴.۷۸ ± ۰.۱۲ oBx), pH (۵.۵۰ ± ۰.۰۰, ۴.۷۴ ± ۰.۰۶); and B۳ – TSS (۲۷.۱۷ ± ۰.۰۷, ۱۰.۲۴ ± ۰.۰۸ oBx), pH (۵.۵۰ ± ۰.۰۰, ۴.۷۷ ± ۰.۰۵) (P < ۰.۰۵). The mean fermentation efficiency (FE) and ethanol productivity (EP) were B۱ (۱۵.۱۷ ± ۰.۰۷%, ۰.۱۲۲ ± ۰.۰۰۱ gL-۱h-۱), B۲ (۱۵.۷۰ ± ۰.۱۸%, ۰.۱۲۶ ± ۰.۰۰۲ gL-۱h-۱), and B۳ (۱۸.۸۰ ± ۰.۱۴%, ۰.۱۵۱ ± ۰.۰۰۱ gL-۱h-۱) (P < ۰.۰۵). All treatment groups attained the maximum ethanol yields at ۷۲ hours of fermentation (P < ۰.۰۵). Agitation at ۲۰۰ rev/min-۱ for ۶ hours gave the optimal FE (%), EP, and ethanol yield. Conclusion: The established condition improved the Bioethanol quality and yield of CP. Thus, optimizing bioethanol production from CP would help enhance sustainable biofuel production without affecting food security.

کلیدواژه ها:

Ethanol ، Fermentation ، Hydrolysis ، Saccharomyces cerevisiae ، Sugars