Inhibitory Mechanism Of Alkaline Pretreatment Inhibitors On Enzymatic Hydrolysis And Fermentation

In this paper,the release of ferulic acid,coumaric acid and other inhibitors and the inhibition of enzymatic hydrolysis of corn straw in alkaline hydrogen peroxide pretreatment were studied.The effects of inhibitors on cellulase were determined by measuring enzyme activity,and the inhibition mechanism of inhibitors on cellulase was determined by measuring the kinetics of enzymatic reaction with microcrystalline cellulose as substrate,and the effects of inhibitors on yeast growth and fermentation were also determined.The main components of corn straw were determined by NREL method,and the amount of cellulase was determined according to the content of cellulose and hemicellulose.The release of ferulic acid and p-coumaric acid during pretreatment with alkaline hydrogen peroxide was determined.At 10% substrate concentration,the release of ferulic acid and p-coumaric acid were 0.14 g/L and 0.4 g/L,respectively.The effects of ferulic acid and coumaric acid on the enzymatic hydrolysis of corn straw before and after washing were studied.The enzymatic hydrolysis efficiency of glucose after washing was increased by nearly 15%.Through the optimization of enzymatic hydrolysis,the optimum enzymatic hydrolysis conditions of cellulase were determined as follows: the amount of enzymatic substrate was 20 mg/g,the temperature was 52?,and the pH was 5.0.Under these conditions,microcrystalline cellulose was used as substrate to study the effects of two inhibitors on the enzymatic hydrolysis of cellulase;Ferulic acid and p-coumaric acid were determined to inhibit cellulose endonuclease significantly by measuring the activity of cellulase;the kinetics of cellulase enzymatic reaction was studied,and the type of inhibition was determined to be competitive inhibitor,and the inhibition groups of the two inhibitors were further explored as methoxy.Groups and phenolic hydroxyl groups.The effects of ferulic acid and coumaric acid on yeast fermentation were also investigated.Adding inhibitors of different concentrations,the effect of inhibitors on yeast growth was studied by measuring growth curve.It was found that ferulic acid had stronger inhibitory effect than coumaric acid: when ferulic acid concentration was 1 g/L,yeast was severely inhibited,but when coumaric acid concentration was 2 g/L,yeast would be inhibited the same effect;the effect of inhibitors on alcohol fermentation was studied by measuring sugar consumption and ethanol production.