Screening Of Lignin Fungi For Degradation Of Hemp And Construction Of A Complex Microbial Community

Lignin is one of the important components of crop straw.Its structure is more complex than cellulose and hemicellulose,so it is difficult to degrade,and the common physical blasting method and chemical reagent treatment method will increase the cost and pollute the environment to a certain extent.Microbial degradation can not only reduce the pollution of chemical reagents,but also reduce the cost,so screening and degradation of lignin microbes is of great significance.The isolated strains were identified by tissue separation and identified by pure culture strains.The sequencing results were compared with Blast analysis,and phylogenetic tree was established to identify taxonomic status of each strain.The screening and rescreening of the strains were carried out after the identification of the strains.The first screening was divided into two parts.First,we observed and recorded the growth of the strains on the carbon source of the lignin,and then used the PDAguaiacol selective medium to cultivate each strain,and further screened the strains with good effect on the degradation of lignin by the size of the color change ring.The three enzyme activities of lignin degradation were taken as indicators.The two screening results showed that the strains with good degradation lignin were Stropharia rugosoannulata,Lentinus edodes and strain 09-27.There are three kinds of enzymes that degrade lignin.The aim of this study is to build up a complex microbial community to make up for the deficiency of the enzyme production characteristics of different strains,so as to make the enzyme production optimal.The construction is divided into three main parts:(1)it is proved that the three bacteria do not have growth inhibition by the flat confrontation test,which is the basis for the subsequent construction of complex bacteria groups.(2)determination of lignin enzyme activity and lignin degradation rate of single strain and complex microbial community.The results showed that the enzyme activity and degradation rate of the lignin in the compound bacteria group were better than the single strain fermentation.The lignin degradation rate of the compound bacteria group was 38.04%,which was higher than the single strain fermentation,indicating that the degradation effect of the compound bacteria group was better.(3)the optimal fermentation conditions were deduced by designing orthogonal test.Under optimal conditions,the results showed that the degradation rate of lignin was 38.04%.After optimization of fermentation conditions,the degradation rate of lignin was improved,the degradation rate was increased by 37.96%,and the degradation rate of lignin was 52.48%.Finally,the changes of the components before and after fermentation were determined.The results showed that each component degraded to different extent,and lignin degradation took precedence over other components.