Comparison of cell growth and ethanol productivity on different pretreatment of rice straw hemicellulose hydrolysate by using Candida shehatae CICC 1766

Abstract

In this work, the cell growth and ethanol productivity was tested forlignocellulosic biomass sugars of overliming-detoxified and NaOH-neutralized rice straw acid hydrolysate by using Candida shehatae CICC 1766. When the acetic acid reached 3 g/L in defined xylose medium, the final ethanol concentration was 33% of that in the medium without acetic acid addition. C. shehatae CICC 1766 could bear lower pH (ethanol yield 13.5 g/L at pH 4.0) in overliming-detoxified hydrolysate. At the optimal pH 5.0 the ethanol yield attended to 16.1 g/L. Ethanol yield in NaOH-neutralized hydrolysate was 13.7 g/L which is better than in overliming-detoxified hydrolysate (7.0 g/L). It suggested that NaOH-neutralized hydrolysate could be directly fermented by using C shehatae CICC 1766. Key words: Rice straw, Candida shehatae, hemicellulose hydrolysate, ethanol fermentation