Isolation, Screening And Phylogenetic Analysis Of Antagonistic Bacillus From Soil Of Tianmu Mountain

Strains of Bacillus produce a wide range of second metabolites with great pharmaceutical importance, are important sources of antibiotic. With the aim to study the diversity of antagonistic Bacillus from soil of Tianmu Mountain National Natural Reserve and to discover new species and new antibiotics, Bacillus strains were isolated by culture-dependent method from soil samples collected from Tianmu Mountain. The isolated strains were screened for nonribosomal peptide synthetase (NRPS) and typeâ… polyketide synthase (PKSâ… ) gene by using specific primer PCR method. The selected strains were then detected for antimicrobial activities and surface active substance, and subjected to phylogenetic analysis based on 16S rDNA sequences, with the expectation to obtain strains of considerable research value for further investigation.Total 35 strains were isolated form soil of Tianmu Mountain. Of them,14 strains possessed NRPS or PKSâ… gene. Among the 14 strains,9 strains showed different antimicrobial activities against to Staphylococcs aureus, Escherichia coli or Candida albicans, and 7 strains could produce surface active substance. Phylogenetic analysis based on the 16S rDNA sequences revealed that 6 of the 14 strains belonged to the genus of Bacillus,6 of the 14 strains belonged to the genus of Paenibacillus and 2 of the 14 strains belonged to the genus of Brevibacillus. Among the 14 strains,4 strains were novel species candidates. One of the novel species candidate strain B5 was subsequently subjected to a polyphasic taxonomic analysis and was classified to be a novel Bacillus species, for which the name Bacillus tianmuensis was proposed.The results of this paper showed that there were diverse antagonistic endospore-forming bacteria existed in the soil of Tianmu Mountain. The screening method based on the specific primer PCR of NRPS or PKSâ… gene combining with antimicrobial activity detection and phylogenetic analysis was a well targeted, rapid and effective method for screening antibiotic producing strains, especially the new strains with potential antibiotic production ability, and leading to the discovery of new antibiotic producing strains and new active metabolites. Moreover, the discovery of new species Bacillus tianmuensis, not only enriched the species of Bacillus, but also provided a good resource for exploring new potential biological active substance.