Bioethanol production by immobilized Sacharomyces cerevisiae var. ellipsoideus cells

Abstract

Bioethanol can be produced by fermentation of sugars from various waste agricultural materials. Whichever system for bioethanol production is chosen, the attention must be paid to the overall economics and energy consumption. The aim of the present study was to investigate the immobilization of Sacharomyces cerevisiae var. ellipsoideus yeast cells for bioethanol production from corn meal hydrolyzates. For this purpose the biocompatible polymers such as polyvinil alcohol (PVA) and Ca-alginate were assessed. The parameters of ethanol fermentation, such as inoculum concentration in different carriers and the choice of a convenient carrier for the efficient ethanol production were studied. The maximum ethanol concentration of 10.05% (w/w) was obtained in the fermentation of corn meal hydrolyzates by 5% (v/v) of inoculum concentration of the yeast immobilized in Ca-alginate using a method of electrostatic droplet generation. The repeated batch fermentation with the yeast immobilized in Ca-alginate indicated that alginate gels degraded after the second fermentation cycle. PVA carrier exhibited better mechanical properties and stability; however lower ethanol concentrations were achieved during the fermentation.