Adewale Allen Sokan-Adeaga - Corresponding author: Department of Environmental Health Science, Faculty of Public Health, College of Medicine, Lead City University, Ibadan, Nigeria
Godson R.E.E Ana - Department of Environmental Health Sciences, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria
Abel Olajide Olorunnisola - Department of Wood Products Engineering, Faculty of Technology, University of Ibadan, Ibadan, Nigeria
Edris Hoseinzadeh - Incubation and Innovation Center, Saveh University of Medical Sciences, Saveh, Iran

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.

Ethanol, Fermentation, Hydrolysis, Saccharomyces cerevisiae, Sugars