PEER-REVIEWED ARTICLE bioresources.com Kukwa et al. (2023). “Bioethanol from rice husk,” BioResources 18(1), 1836-1847. 1836 Conversion of Waste Products Derived from Rice Processing Industry Into Bioethanol Rose E. Kukwa, a,c, * Donald T. Kukwa, a,b Winifred U. Nande, c and Michael T. Tse a The effects of acid and alkali hydrolysis, as well as rice husk varieties (pure and mixed), on bioethanol production using saccharification and fermentation, were investigated in this study. Microbes such as Saccharomyces cerevisiae are currently used for fermenting agricultural wastes to bioethanol, an environmentally friendly alternative to petroleum energy sources. Rice husks were ground to a fine powder, then hydrolyzed with acid and alkali, and incubated for five days. A refractometer was used to perform a sugar reduction test, which determined the presence of fermentable sugar in the media. The parameters revealed that the variety of rice husk used did not affect the ethanol percent yield, which was 14.8 ± 0.5% and 15.0 ± 0.5% for the pure and mixed varieties, respectively; however, there was a substantial difference in the percentage yield in the method of pre-treatment. The percentage yield of ethanol in the acid pre- treated sample was higher (14.8 ± 0.5% and 15.0 ± 0.5%) than that of the alkali (6.1 ± 0.5% and 4.8 ± 0.5%). The presence of alcohol in the sample was confirmed by FTIR analysis, while GC-MS identified the specific compounds and their percentage composition - ethanol (9.67%). This suggests that using H2SO4 in the hydrolysis of rice husk is a promising and effective method for producing bioethanol. DOI: 10.15376/biores.18.1.1836-1847 Keywords: Rice husk; Hydrolysis; Fermentation; Bioethanol Contact information: a: Department of Chemistry, Benue State University, Makurdi, Nigeria; b: Department of Chemical Engineering Durban University of Technology, Durban, South Africa; c: Centre for Food Technology and Research, Benue State University, Makurdi, Nigeria; * Corresponding author: erdoo.rose@gmail.com INTRODUCTION The management of solid waste from the agriculture and food processing industries, which causes environmental contamination, is one of the most serious concerns at hand today. The need for an alternative energy source that is sustainable, renewable, economically viable, environmentally friendly, and does not compete with human food sources has also been sparked by the high cost of producing fossil fuels, their inability to be replenished, and the rising demand for food and energy due to the growing human population. As a result, the use of rice husk for future supplies of ethanol is a means to lessen reliance on petroleum-based fuels, mitigate the effects of global warming, and efficiently manage agricultural waste. Ethanol is a clear, colourless, volatile, inflammable liquid produced either by synthesis or fermentation. Synthetic ethanol is produced by the hydration of ethylene, which is a petrochemical process with a high negative impact on the carbon economy. Fermentative ethanol, on the other hand, is produced from biomass, which can either be starchy or lignocellulosic material. Biomass-based ethanol, commonly referred to as