Authors Contributions
B.Z. developed the concepts, designed and led the research, contributed to data analyses and wrote the paper. Y.Z.X. and K.L. conducted all the research work and analyses. S.H.Y. contributed to PLFA analysis. X.D.Z. and H.B.H. contributed to amino sugar analysis. J.D.M. and Y.L.Z contributed to NMR analysis. C.C and D.C.O. provided constructive comments and suggestions to improve the manuscript. All the authors contributed to the writing of the paper.