Dilute acid pretreatment of wheat straw for simultaneous saccharification and fermentation by enzymes and Candida wickerhamii Y-799

摘要

Wheat straw was pretreated with dilute acid for straw subsequent fermentation. The fermentation was carried out in simultaneous saccharification and fermentation (SSF) method by cultivation of C. wickerhamii for 3 days at 37 deg and in the presence of enzyme. Various parameters such as the acid concentration [1-4 percent (W/V), 98 percent H_2SO_4] under pressure [1 kg/cm~2, 120 deg C, 30 min] and the source of cellulase [3 sources, individually or in mixture and in the presence of pectinase] were studied. The enzyme was added at 10g or ml enzyme/10g treated straw/L. The end products of ethanol, residual reducing sugar (as glucose), total higher alchols (as hexanol) centration pretreatment of the straw increased the end products of total higher alcohols and total acidity but, reduced the residual reducing sugar. No significant change in the ethanol content was observed by using the enzyme in single or in mixture. It was nearly constant at 0.07 mg/ml. Maximum values of total higher alcohols (as hexanol) and total acidity were 73 X 10~(-4) mM/ml and 4.56 mg/ml, respectively and minimum amount of the residual reducing sugar was 0.78 mg/ml in mixture of enzyme at 4 percent acid concentration pretreatment.