Isolation And Phylogenetic Studies Of Viable But Non-Culturable Bacteria From Xinjiang Soil Samples

There are a huge amount of microbial resources in Xinjiang region due to its special environment and less human interference.But we can only obtain the cultivated bacteria form environment less than0.01-10% by using traditional pure cultivating methodat present, most of them are in viable but non-culturable (VBNC) state and have not been recognized, more can’t be used by us.Asa huge microbial resources in nature, identification and functional exploitation of VBNC bacteria resources deserve our attention.This thesis focused on the resuscitation and isolation of VBNC state bacteria from soil samples collected from Xinjiang region using most probable number(MPN) culture system based on resuscitation promoting factor(Rpf). Totally 60 strains were isolated, including 48 VBNC bacteria, which enriched the laboratory’s microbial resources. The VBNC isolates belonged to 16 different genera (Bacillus, Brevibacillus, Staphylococcus, Brevibacterium, Arthrobacter, Kocuriac, Microbacterium, Cellulosimicrobium, Rhodococcus, Streptomyces, Enterobacter, Escherichia, Brevundimonas, Pseudomonas, Ensifer and Herbaspirillum. Among these isolates, Bacillus was the genus with largest numbers(40%); and Actinomycetes was the group with most abundant variety (7 genera). The preliminary investigation results indicated that the VBNC strains isolated from Xinjiang soils have significant diversity and wide distribution.14 of the isolates were considered novel taxa by current research. Polyphasic taxonomy including morphology, physiological and biochemical tests, chemotaxonomy and molecular characteristics were carried out for strain DSXY973.This study also indicated that Rpf can effectively resuscitate not only the high G+C content Gram-positive organisms, but also the low G+C content Gram-positive organisms, including the most sensitive genus Bacillus. Furthermore, Rpf also stimulates the growth of several other Gram-negative organisms. In a word, this research providesscientific basis for the resuscitation and isolation of VBNC bacteria resources from natural environment by using Rpf. It also provides a new insight and method of the development of novel species and further application study of VBNC bacteria.