14-34: Effects of lignin of sweet sorghum on enzymatice activity of β-gluconase based on different pretreatments and immobilized enzyme

It has been proven that the accumulation of cellubiose in enzymatic hydrolyzate of cellulose inhibited the hydrolysis of cellulose.β-gluconase as an important component of cellulase can convert cellubiose into glucose and improve the enzymatic hydrolysis rate of cellulose. So β-gluconase is usually additively added to get higher cellulose conversion rate. However, extra utility ofβ-gluconase will increase the cost of enzymatic saccharification process. Due to the solubility of the substrate, it is possible to use immobilized β-gluconase to enhance the hydrolysis of cellulose and decrease the cost of cellulase via recycle of the immobilized enzyme. In our study, an immobilized ofβ-gluconase was prepared via a mesoporous hydrogel method. The enzymatic activity of immobilized β-gluconase did not decrease after six times of recycle. The effect of lignin of sweet sorghum obtained from various pretreatment on the enzymatic activity ofβ-gluconase was investigated on the basis of the immobilized β-gluconase. The results demonstrated the existence of lignin could decrease 10-20% of enzymatic activity of β-gluconase, while this effect was not observed when immobilized β-gluconase was used. Moreover, the lignin obtained from alkaline pretreatment had the stronger negative impact on hydrolysis than the sulfuric lignin. The result of electrophoresis after adsorption experiment confirmed there was obvious non-productive adsorption of β-gluconase on lignin of sweet sorghum.