Screening of high-efficiency lignocellulosic degrading bacteria and study on the degradation effect of straw by complex microbial systems
In order to isolate,screen and construct complex microbial systems that could degrade lignocellulose for corn straw efficiently,this experiment used sodium carboxymethyl cellulose(CMC-Na)as carbon source.The strains were screened by Congo red plate dilution method,and the carboxymethyl cellulose activity(CMCase),filter paper enzyme(FPA)and lignin peroxidase(Lip)were determined for further screening.Five strains with high enzyme production capacity were screened from rotten rice straw,forest humus and humus soil,of which K3 identified by 16S rDNA gene sequence as Klebsiella sp.,P4 as Pantoea ananatis,H7 as Herbaspirillum seropedicae,R18 as Raoultella ornithinolytica,and C25 as Citrobacter freundii.According to the antagonistic test,eight groups of complex microbial systems were constructed.Based on enzyme activity determination,the complex microbial systems B(P4,R18),C(R18,C25),F(K3,R18,C25),G(P4,R18,C25)and H(K3,P4,R18,C25)were finally selected as the dominant complex microbial systems for study on degradation effect of corn straw.The results showed that the enzyme activity of the complex microbial systems was higher than that of the single strain,and the complex microbial systems F,G and H had a better degradation effect on the corn straw.After 26 days of treatment with them,the weight loss rate of the corn straw reached 32.96％,36.24％and 46.41％,respectively.The degradation rates of cellulose,hemicellulose and lignin of corn straw by complex microbial system H were 28.02％,36.31％and 25.16％,respectively.The complex microbial system H had the best degradation effect on lignocellulose degradation of corn straw and had good application potential.
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维普
