Characterization and screening of antimicrobial activity of Micromonospora strains from Thai soils

Abstract

Aims: Rare actinomycete strains were isolated from mountain soils and island soil collected in Thailand. They were screened for antimicrobial activity and characterized for their secondary metabolites. Methodology and results: The strains were isolated by the standard dilution technique using starch casein nitrate agar. They were identified and characterized based on the phenotypic, chemotaxonomic and genotypic characteristics. The chemotaxonomic characteristics of ten isolates coincided with those of the genus Micromonospora. On the basis of phylogenetic analysis using 16S rRNA gene sequences and DNA-DNA relatedness, they were divided into 6 Groups, ASC19-2-1 (Group A) was identified as Micromonospora marina; AL8-8 and AL10-3 (Group B) were M. aurantiaca; AL7-5 (Group C) was M. chalcea; AL3-16 and AL9-20 (Group D) were identified as M. chokoriensis; AL9-13 and AL9-22 (Group E) were M. tulbaghiae; and AL1-15-2 and AL1-16B (Group F) were M. chersina. On the primary screening, only the isolate AL7-5 (Group C) could inhibit Kocuria rhizophila ATCC 9341. This isolate produced rakicidin when cultivated on A3M, A11M and A16 media and produced compound BU4664L only on A16 medium. Conclusion, significance and impact of study: The isolation and characterization of the rare actinomycetes from Thai soils will be useful for the taxonomic study and for the discovery of bioactive metabolites that are active against microorganisms.

Multifunctional in vitro, in silico and DFT analyses on antimicrobial BagremycinA biosynthesized by Micromonospora chokoriensis CR3 from Hieracium canadense

“…Micromonospora chokoriensis was first isolated as a novel isolate from the sandy soil in Chokoria, Bangladesh 17 . Later, it was reported from the mountain soil in Thailand 10 and from the desert soils of Chile and China 11 , 12 . Previously a study 18 reported the isolation of M. chokoriensis strain B020 as an endophyte from wild medicinal plants.…”

“…Up until now, about 65 species have been reported 9 from different environments such as soil, sediments, water, and root nodules 10 that are reported to produce antibiotics such as diazepinomicin, lomaiviticins A and B, lupinacidins A and B, netamicin, and tetrocarcin A 9 . Most recently, antimicrobial metabolites such as sagamycin, gentamicin, halomicin, ivermectin, mutamicin, and mycinamicin have also been identified in them 11 . Since this genus is second to Streptomyces as a source of novel metabolites 12 , new species from it remain a focus of research 9 .…”

Bioactive Metabolites From Acid-Tolerant Fungi in a Thai Mangrove Sediment

“…Previously, most studies of microbes from Thai mangroves have focused on bacteria and yeast (Limtong et al, 2007(Limtong et al, , 2008Am-In et al, 2008Atipan et al, 2012;Songsumanus et al, 2013;Wongwongsee et al, 2013;Hwanhlem et al, 2014;H-Kittikun et al, 2015;Wanapaisan et al, 2018). Fungi from Thai mangroves, especially acid-tolerant fungi and their bioactive metabolites under conditions of acidic stress, have not previously been investigated.…”