Enzymatic saccharification of alkali pretreated rice straw.

Dilute solutions of H2SO4,NaOH,ammonia and H2O2 were evaluated as pretreatment reagents for improving the enzymatic saccharification of rice straw at room temperature (28 ℃). The highest saccharification rate was achieved in the case of rice straw pretreated with 2% NaOH. Mild alkali pretreatment resulted in a majority removal of lignin,but higher than half of hemicellulose was remained in the material. The compound enzyme produced by T. koningii QF-02 was more suitable for the hydrolysis of pretreated rice straw than the mixture of two commercial cellulases. The optimum temperature and pH for the hydrolysis of pretreated rice straw of the compound enzyme was 50℃ and 4.8 respectively. For the hydrolysis of alkali pretreated rice straw by the compound enzyme,the optimal hydrolysis time,enzyme loading and substrate concentration were determined as 48 h,10 FPU/g biomass and 8% (w/v),respectively.