Study On The Diversity,enzymes And Antibiotic Activity Of Bacteria From Badain Jaran Desert In Gansu Province

Objective:In order to take insight into the diversity and ecological function,explore strains with the ability of producing enzyme and inhibiting human pathogens,as well as obtain unique strains for the development and application of novel and highly active antibiotics and enzyme preparation,bacteria of Badain Jaran desert in Gansu Province was investigated.Methods:1.The diversity and functional profiles of microbes were analyzed by high-throughput sequencing technology.2.The bacteria were isolated from desert based on culture-dependent method.Isolations were identified and classified through16 S r RNA gene sequence similarities.Then,the representative strains with distinct phylogenic distances were employed for amylase,protease and esterase activity screening by using the plate hydrolysis spot method.3.Detection of antibiotic biosynthesis genes with representative actinomycetes was performed by PCR.For the positive strains,antibiotic activity was carried out by traditional filter paper method to further screen the actinomycetes with inhibitory effects on 6 pathogenic bacteria.4.Identification of two potential new species of actinomycetes were performed by heterogeneous classification method.At the same time,their secondary metabolism was analyzed by anti SMASH bioinformatics methods.Results:1.A total of 3561 OTUs from desert soil were affiliated to 34 phyla,75 classes,160 orders,228 families and 354 genera.Among them,51 functional profiles were detected.2.A total of 368 strains of bacteria were obtained from this desert,among which actinomycetes was the most abundant member with the frequency of 48.10%.Among 180 typical strains,128 strains were capable of functional enzymes producing.The isolates with amylase,protease,esterase came in 18.33%,51.67% and 55.55%,respectively.3.26 strains from 80 tested actinomycetes had at least one of PKS-I,PKS-II,NRPS biosynthetic gene clusters.Among positive strains,9 strains,14 strains,17 strains showed antibiotic activity against Bacillus cereus,Staphylococcus aureus and Cryptococcus neoformans,respectively.4.Two novel species belonging to the genus Arthrobacter were named Arthrobacter halotolerans and Arthrobacter coccineus respectively,both which host 5 gene clusters related to synthesis of secondary metabolites.Conclusion:1.There is a large number of bacteria,some archaea and unidentified microorganisms thriving among Badain Jaran Desert in Gansu Province,which has a potential value with microbial resources mining.2.Among these strains,the phylum Actinobacteria is the most widely distributed microbial group.The strains producing functional enzymes have high genetic diversity.Among these isolates,the main functional strains belong to the genus Arthrobacter and Streptomyces.These actinomycetes are potential sources of enzyme drugs.3.Actinomycetes isolated from this desert can be potential resources for the development of polyketones and non-ribosomal peptide anti-infective drugs against gram-positive bacteria and pathogenic fungi.4.There are new microbial resources isolated from this desert,among which two new species at the genus Arthrobacter have the potential ability to produce novel NRPS-PKS heterozygosity,?-lactones and unidentified natural compounds.It will provide new clues for the discovery of new antibiotics.