Study on Effects of Degradation of Cassava Dregs by Adding Enzymes

SHANG Qian; WANG Yinghui; ZHANG Ruijie; YU Kefu

doi:10.3969/j.issn.1003-6504.2017.01.006

Abstract：Dregs from cassava starch production is degraded by use of enzyme technology and the by-product can be recycled to make feeds and ethanol.In this paper the optimum reaction condition of three kinds of enzyme and the influence of substrate concentration on the reaction were explored;and the optimized combination of three enzymes was determined through the orthogonal experiment,which resulted in the optimal condition of cellulose:pH,the temperature 60 ℃ and the enzyme amount 6 400 U/g (cassava dreg);the optimal conditions for saccharifying enzyme:pH value was 4,the temperature 90 ℃ and the enzyme amount is 2 000 U/g (cassava dreg);and the optimal condition for α-amylase:pH value 6,the temperature 60 ℃ and the enzyme amount 480 U/g (cassava dreg).The lower the ratio of solid to liquid,the more sufficient contact of the enzymes and substrates and the higher extraction rate would be.The experiment also showed that the final reducing sugar concentration of cellulose enzyme (7.15 mg/mL) from the degradation of cellulase was higher than the theoretical reducing sugar concentration (7 mg/mL);and compared to α-amylase saccharifying enzyme was more comprehensive in effectiveness,had higher reducing sugar concentration and longer reaction time.It was found that cellulase,sacchadfying enzyme and a-amylase when put together possessed a remarkable synergy,under which the concentration of reducing sugar could be greatly increased (by 97.92％) compared with the action of single enzyme and the action of traditional double enzymatic method as well.