Bioconversion of corn straw to ethanol by cellulolytic yeasts immobilized in Mucuna urens matrix

Abstract

Production of bioethanol from corn straw by cellulolytic yeasts immobilized on Mucuna urens was investigated. Yeast isolates were screened for amylase, cellulase and ethanol production. Effect of bead size, inoculum load, substrate concentration, pH and bead reusability were studied. Bioethanol production was optimum with 4 mm bead size, 10% substrate concentration, pH 4.5 and 10% inoculum load. Maximum ethanol production (55.27 g/L) was achieved by immobilized Saccharomyces diaststicus. Immobilized yeast cells were re-used repeatedly without obvious loss of activity. This study showed that yeasts immobilized on Mucuna urens can effectively utilize lignocellulolytic materials and produce ethanol from it. Keywords: Bioethanol, Yeasts, Immobilization, Mucuna urens, Saccharomyces diastaticus