Screening And Degradation Pathways Of Lignin-degrading Bacteria

Lignin is a complex biological macromolecule with amorphous,three-dimensional network structure that widely exists in plants.It is an important member of the earth’s carbon cycle and the most abundant renewable resource of aromatic ring compounds in the world.The complex aromatic structure of lignin is also an important factor that makes it difficult to degrade,and it also becomes a barrier for the utilization of lignocellulose.Researchers have been studying how to separate and effectively utilize lignin for a century.Microorganisms are favored by scientific researchers because of their low energy consumption,low pollution,and strong adaptability.The study of microbial degradation of lignin is of great significance to the reuse of lignin.The study of lignin degradation process may provide a new idea for the industrialization of lignin degradation.This paper selection of lignin degrades with strongly residualization from corn core residues,conducts research on lignin degradation enzyme activity and metabolites by optimization of degradation conditions,and the main research results are:1.Screening out strains with strong ability to degrade lignin from corncob residue waste:bacteria: Burkholderia multivorans SZ-2 and fungi: Bjerkandera adusta SZ-4,they were found to degrade lignin well.After SZ-2 was optimized,the enzymatic activities of lignin-degrading enzymes reached Li P=777.31 U/m L,Lac=67.71 U/m L,Mn P=234.68 U/m L,respectively,indicating that Burkholderia polyphaga was living in Basic research on substance degradation provides a reference.After optimizing the conditions of SZ-4,the enzyme activity of lignin peroxidase was Li P =262.31 U/m L.It can be seen that the two strains of microorganisms screened have a certain effect on the degradation of lignin.Provides one more selection strain for lignin degradation.2.Through testing,it was found that under the promotion of PDB,the degradation rate of fungus SZ-4 on lignin was as high as 98.38% after 5 days of incubation,and it could degrade a variety of dyes,such as: Alizarin red,Congo red,aniline blue,bromophenol blue,bromocresol green,Coomassie brilliant blue G250,methylene blue,and the degradation rate of some of these pigments is close to 100%.In addition,SZ-4 has decolorizing effect on lignin and various dyes.The multiple functions of bacterial strain SZ-4 have changed the current situation that most of the existing strains have a single function,and have great application potential in degrading lignin and degrading dyes in the environment.3.Use GC-MS technology to analyze the metabolites produced during lignin degradation of the two strains,detecting a plurality of benzene ring compounds,alcohols,acid small molecule compounds,and speculatively decomposing lignin first.The benzene ring small molecular compound,and then the enzymatic reaction is enzymatically hydrolyzed by a benzene ring small molecule compound,and finally enters the TCA cycle(tricarboxylic acid cycle).