Study On Phanerochaete Chrysosporium And Aspergillus Niger Degradation Of Straw And Ethanol Fermentation

Using corn straw as raw material,Phanerochaete Chrysosporium can degrade lignin in straw degradation,this makes Aspergillus niger can produce cellulase and touch straw cellulose easily and quickly.Reduced sugars were converted to ethanol by Saccharomyces cerevisiae.Cellulose degradation,saccharification and fermentation process can be carried out at the same time.The sugar produced by the hydrolysis of cellulose can be quickly fermented into ethanol,and the feedback inhibition effect on cellulase can be eliminated.In this paper,through the determination of the enzyme activity,the excellent strains were selected from the strains with high cellulase production,and the complex strains were constructed.Saccharomyces cerevisiae was used to degrade the carbohydrates produced by cellulose in the straw,and then to ethanol.The optimum conditions of microbial growth and fermentation were studied by the combination of lignin degradation,cellulose degradation and fermentation.The main conclusions are as follows:(1)Strains of endoglucanase activity,FPA determination(FPA),exoglucanases activity and beta glucosidase activity,from the D series(separation of dominant strains cultured in compost),Z series(dominant strains found in plant stems)screened strains D2,D2-1,Z14.(2)The different strains of the same series and the same series were used to make a combination of the 22 enzymes,and the enzyme activity of the 4 enzymes was used as the index to determine the efficient Cellulase Producing Strain of D2+D2-1.(3)Use filter paper activity as index,single factor test and response surface analysis of the influencing factors of the optimal fermentation conditions of mixed bacteria,the optimum conditions for D2:D2-1=2:1,fermentation time 6 D,6%inoculation amount,fermentation temperature 28.After optimization,the enzyme activity could reach 156.262 U/mL,and the enzyme activity(U/mL)increased by about 37.1%.(4)The optimum conditions for the degradation of lignin in corn straw are:temperature of 32 DEG C,pH6,inoculum size of(diameter 8mm),treatment time was 15 days.The degradation rate of lignin could reach 47%after optimization of degradation conditions,which was increased by about 42.4%compared with that of the first 33%.(5)The optimal fermentation conditions are determined.The orthogonal experiment was carried out by selecting the fermentation temperature,initial pH and yeast addition.The optimal fermentation conditions were as follows:natural pH,inoculation amount of 8%,and fermentation temperature of 34 DEG C for the first time in 5 days.The optimum fermentation conditions are:the yield of ethanol was increased to 7.1%,which was increased by about 56.3%compared with that of the non optimized one,which was about 3.1%.