The Study Of Noval Species And Bioactive Metabolite Produced From Actinomycetes In Mangrove Soil

Mangrove are located in the tropical and subtropical transition coastal regions. Due to the long immersion by the sea, mangrove has formed a special ecological environment with the characteristics of sea and land,and been an ideal place for isolation of actinomycetes. In order to study the diversity of actinomycetes species and their natural products in Thailand mangrove soils, 24 rhizosphere soil samples from Thailand mangrove were collected cumulatively. Different culture media were used to isolate actinomycetes, and bioactive metabolites of actinomycetes were screened and detected.For the first collection of 14 soil samples, 7 different culture media were used for isolating actinomycetes and 109 strains were obtained. For the second collection of 10 soil samples, 10 different culture media were used for isolating actinomycetes and 306 strains were obtained. It were identified as Streptomyces, Micromonospora mainly.Analysis of 16 S rRNA gene sequences of the isolated strains from the first isolated actinomycetes revealed that approximately 1/5（20 %） individual strains were found to have low similarity（<99 %） comparing with the known actinomycetes in database. It suggested that these strains may be the new species. The polyphasic taxonomy including medium characteristics, morphological characteristics, physiological and biochemical experiment, chemistry experiment and the molecular experiment were carried out to identify one strain（strain HV38）. The results indicated that target strain had an obivious difference with the reference strains. It can be concluded that strain HV38 represents a novel species of the genus Streptomyces, for which the name Streptomyces ferrugineus sp. nov., is proposed.In addition, FM3 fermentation medium was used for the bioactive screen of second metabolites. To the first 109 strains of actinomyces,antimicrobial screening results suggested that 32 strains（29.3 % strains） were active against E. coli ATCC 25922, 55 strains（50.4 % strains） were active against S. aureus ATCC 51650, and 35 strains（33.9 % strains） were active against C. albicans ATCC 10231. To the second 306 strains of actinomyces, antimicrobial screening results suggested that 49 strains（16.1 % strains） were active against E. coli ATCC 25922, 123 strains（40.3 % strains） were active against S. aureus ATCC 51650, and 73 strains（23.9 % strains） were active against C. albicans ATCC 10231. Based on the analysis of second metabolites with HPLC, LC-MS and ANTIBASE₂012 database, one possible novel species strain（Streptomyces sp. RCY534） from the secend isolated actinomycetes was chosen for natural products study.For the candidate strain RCY534, 50 L fermentation broth with the optimized fermentation conditions was accumulated to obtain a crude extract 28.0 g. Then by the positive phase silica gel column, reverse phase silica gel column, sephadex LH-20 and semi-preparative HPLC, 14 compounds were islolated and characteristiced by MS and NMR etc.. Compound RCY-1—RCY-3 were identified as Chrysomycin C, Chrysomycin A and Chrysomycin A, respectively. Meanwhile, the identification of others compounds are in progress.