A Study Of Pretreatment Technology On Enzymatic Hydrolysis Of Corn Stalk

The crop straw resources is very plentiful in China，but it is not used reasonably for along time，2/3of it is burned in the field.It caused serious waste and environmentpollution.We produce fuel alcohol,L-lactate etc.with corn stalk,which reduce the environmentpollution,and new raw material is found used for L-lactate production.The pretreatment beforeenzymolysis is a key point of enhancing enzyme hydrolysis efficiency.This paper compared corn stalk enzymolysis after mechanical crushing with chemistrycooking pretreatment firstly，then researched corn stalk enzymolysis with malt enzyme complexand cellulase.The character of the product and mechanism of enzyme hydrolysis of corn stalkpowder is analysed.There is direct relationship between cellulose enzymolysis result and pretreatment ofcorn stalk.The mechanical disintegration can enhance enzymolysis efficiencyeffectually,along with corn stalk mechanical crushing intensity increasing,the contents ofglucose of zymohydrolysis increasing. In addition，when corn stalk is crashed to100-300nmparticle，the yield of glucose raised markedly.It raise6-fold than40～60mesh corn stalkenzymolysis yield.When the particle of corn stalk is bigger(under200mesh),corn stalkenzymolysis result is better after chemical cooking pretreatment.The results showed thatmechanical crushing intensity increasing,lignocellulose is destroyed more seriously. Thedegree of polymerization of corn stalk lessening gradually,enzymolysis result increasing,lignin is dissolved out more easily.There is some synergistic effect between malt enzyme complex and cellulosedegradation of corn stalk.The contents of glucose of malt enzyme complex and cellulosehydrolysis together is higher than cellulose alone.With malt quality adding，synergistic effectstrengthening.Furthermore，when the dosage of cellulose is less，synergistic effect is moreremarkable.There is synergistic effect still between malt enzyme complex after80℃hightemperature and cellulose.The enzyme activity determination result indicate that α-amylase，prolease，polyphenol oxidase have principally synergistic effect to cellulose hydrolysis of corn stalk.By the analysis of product character and mechanism of enzymatic hydrolysis of cornstalk powder,glucose is not only produced but also xylose,when cellulose hydrolyze cornstalk.Through GC-MS analysis,we can judge that glucose have optical isomer in enzymesolution of corn stalk.It means that it is mixture of D-glucose and L-glucose.Along with thelessening of granularity of corn stalk,cellulase hydrolysis can destroy ether bond,glycosidicbond,acetal bond and some other bonds between lignin-carbohydrate complexes(LCC) invarying degrees.The less granularity,the more amount of hydrolysis saccharide.When itreaches100-300nm particle,some xylose is dissolve out under the condition of pH4.8.