Changs of Microorganisms in Mao Bamboo Stumps at Different Decomposition Degrees

The microbial flora in bamboo stump at different decomposition degree was studied. The results showed that the logarithmic values of bacterial concentrations ranged from 5.477 to 7.380; the logarithmic values of fungal concentrations ranged from 5.301 to 6.903; the logarithmic values of actinomycetes concentrations ranged from 5.740 to 7.000; the logarithmic values of cellulose-degrading bacterial concentrations ranged from 4.301 to 6.447; the logarithmic values of lignin-degrading bacterial concentrations ranged from 4.415 to 6.799. During the decomposition of bamboo stump, all the microorganisms grew rapidly at the initial stage; the logarithmic values of bacterial, fungal and actinomycetes concentrations changed constantly at the middle stage; and the logarithmic values were all higher at the late stage.There were assistance and competition among microorganism to certain extent. Understanding the decomposition rule of bamboo stump before its cutting down can provide some reference for the future decomposition of bamboo stump, and provide basic data for the isolation of microorganisms from bamboo stump at the species level.

Widespread Bathyarchaeia encode a novel methyltransferase utilizing lignin-derived aromatics

Lignin degradation is a major process in the global carbon cycle across both terrestrial and marine ecosystems.Bathyarchaeia,which are among the most abundant microorganisms in marine sediment,have been proposed to mediate anaerobic lignin degradation.However,the mechanism of bathyarchaeial lignin degradation remains unclear.Here,we report an enrichment culture of Bathy-archaeia,named Candidatus Baizosediminiarchaeum ligniniphilus DL1YTT001(Ca.B.ligniniphilus),from coastal sediments that can grow with lignin as the sole organic carbon source under mesophilic anoxic conditions.Ca.B.ligniniphilus possesses and highly expresses novel methyltransferase 1(MT1,mtgB)for transferring methoxyl groups from lignin monomers to cob(I)alamin.MtgBs have no homology with known microbial methyltransferases and are present only in bathyarchaeial lineages.Heterologous expression of the mtgB gene confirmed O-demethylation activity.The mtgB genes were identified in metagenomic data sets from a wide range of coastal sediments,and they were highly expressed in coastal sediments from the East China Sea.These findings suggest that Bathyarchaeia,capable of O-demethylation via their novel and specific methyltransferases,are ubiquitous in coastal sediments.