In this work,screening by using methanol as the sole carbon source,a methylotrophic bacteria,namely NH8,was isolated from soil samples,and was identified preliminarily as Serratia marcescens based on phylogenetic analysis of 16S rRNA gene sequence.With multiple alignments of nucleotide sequences against pqq genes cluster,some primers amplifying the pqq genes were designed by Primer 5 software.Therefore,the pqq genes cluster,which was related to PQQ biosynthesis,had been isolated from Serratia marcescens NH8 by PCR amplification.The pqq genes fragment of 5 535 bp had six open reading frames including pqqA,pqqB,pqqC,pqqD,pqqE,pqqF genes and showed 99% homology to pqq genes of Serratia marcescens WW4.Meantime,the structures and functions of each gene in pqq genes cluster were analyzed.The result show that 5 genes of pqqB,pqqC,pqqD,pqqE,pqqF construct one operon for regulating PQQ biosynthesis in Serratia marcescens NH8.