Bioethanol production from white onion by yeast in repeated batch

Abstract Considered to be the cleanest liquid fuel, bioethanol can be a reliable alternative to fossil fuels. It is produced by fermentation of sugar components of plant materials. The common onions are considered to be a favorable source of fermentation products as they have high sugar contents as well as contain various nutrients. This study focused on the effective production of ethanol from an endemic Iranian white onion (Allium cepa L., Dorche cultivar) by the yeast "Saccharomyces cerevisiae" in repeated batch. The results showed that the total sugar concentration of onion juice was77.3 g/l. The maximum rate of productivity, ethanol yield and final bioethanol percentage was 8 g/l/h (g ethanol per liter of onion juice per hour), 40 g/l (g ethanol per liter of onion juice and 93 %, respectively