Abstract：Screening lignin-degrading bacteria and studying its degradation properties could realize the efficient use of lignocellulosic, and provide high value-added raw materials for the chemical industry, and alleviate the contradiction of shortage of raw materials. In order to obtain more excellent and applicable bacteria for the biodegradation of lignin, a Bacillus sp. strain named MN-13 was screened from fresh manure of Bos taurus via heating enrichment, decolorization of aniline blue in plate cultivation combination with detection of enzyme activity. Strain MN-13 decolorized significantly aniline blue, oxidized Mn2+ and veratryl alcohol. According to morphology, physiological and biochemical characteristics, sequence analysis of 16S rDNA and gyrB gene, strain MN-13 was identified as Bacillus amyloliquefaciens (GenBank No. KP292553). Lignin degradation characteristics of strain MN-13 showed that this strain could efficiently degrade lignin in corn stalks with lignin-degradation rate of 44.8% and NDF-degradation rate of 29.0% after 24 d of inoculation. In the process of lignin-degradation mediated by strain MN-13, the ligninolytic peroxidase which was similar to lignin peroxidase (LiP) and manganese peroxidase (MnP) could be produced and the stage of highest enzyme activity was consistent with the period of the maximum lignin-degradation amplitude. Gas chromatography-mass spectrometry (GC-MS) analysis results of lignin degradation products showed that strain MN-13 could degrade lignin into H, G and S phenols by the fission of β-O-4, Cα-Cβ and Cβ-Cγ bonds and, oxidation of Cα and Cγ. Screening of B. amyloliquefaciens MN-13 provided a new ligninolytic microorganism which would enrich the bacteria resource capable of degrading lignin. Meanwhile, lignin degradation characteristics of B. amyloliquefaciens MN-13 would provide a reference for further application of Bacillus sp. strains in the lignin-degradation.
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