Diversity, antimicrobial capabilities, and biosynthetic potential of mangrove actinomycetes from coastal waters in Pahang, Malaysia

Zainal Abidin, Zaima Azira and Khan Chowdhury, Ahmed Jalal and Abdul Malek, Nurfathiah and Zainuddin, Zarina (2018) Diversity, antimicrobial capabilities, and biosynthetic potential of mangrove actinomycetes from coastal waters in Pahang, Malaysia. Journal of Coastal Research, Special Issue 82 Fall. pp. 174-179. ISSN 0749-0208 E-ISSN 0749-0208

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Abstract

Actinomycetes are biotechnologically important for their unparalleled capability to produce various bioactive secondary metabolites. The diversity and antimicrobial capabilities were investigated for actinomycetes, which were previously isolated from mangrove sediment of the Pahang mangrove forest. The biosynthetic potential using type I polyketide synthase (PKS-I) and nonribosomal peptide synthetase (NRPS) genes and the morphological characteristics of actinomycetes were also determined. Representative isolates were selected from five sampling locations in the Kuantan mangrove forest. Antimicrobial activities of crude ethyl acetate extract of these actinomycetes against five test microorganisms—Bacillus subtilis, Candida albicans, Escherichia coli, Serratia marcescens, and Staphylococcus aureus—were evaluated using the disc diffusion method. Actinomycetes were identified using the 16S rRNA gene sequence, and culture characteristics of selected actinomycetes were determined by inoculating the strains onto a set of agar media, namely, starch–yeast extract agar, inorganic salt–starch agar, starch–casein agar, and nutrient agar. Screening of the biosynthetic potential of these actinomycetes was achieved through polymerase chain reaction amplification of PKS-I and NRPS genes. Most isolates exhibited moderate to good antimicrobial activities toward B. subtilis and S. aureus, and a few inhibited C. albicans and E. coli. Streptomyces sp. K1-01 and Streptomyces sp. K2-03 showed antimicrobial activity against all test organisms, suggesting a broad-spectrum nature of the compounds they produced. Mangrove actinomycetes enumerated in this study demonstrated a high level of diversity, and they were distributed among nine genera. Streptomyces and Micromonospora were the most predominant genera observed,alongside Micrococcus, Gordonia, Nocardia, Dietzia, Pseudonocardia, Saccharopolyspora, and Verrucosispora. However,there is no direct correlation between antimicrobial capability and presence of PKS-I and NRPS in actinomycetes.Cultural characterization of selected actinomycetes revealed two interesting isolates Micromonospora sp. K3-13,producing blue diffusible pigment, and Streptomyces sp. K2-03, producing purple diffusible pigment. This study demonstrated the potential of mangrove sediment as a new resource for highly diverse actinomycetes with biosynthetic capabilities. Detection of PKS-I and NRPS in these actinomycetes helps to establish a focus group that can be applied for future study of the natural product, particularly in antibiotic production.

Item Type:	Article (Journal)
Additional Information:	4416/67808
Uncontrolled Keywords:	Actinomycetes, antimicrobial, biosynthetic potential, diversity, mangrove
Subjects:	Q Science > QR Microbiology
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Science Kulliyyah of Science > Department of Biotechnology Kulliyyah of Science > Department of Marine Science Kulliyyah of Science > Institute of Oceanography and Maritime Studies
Depositing User:	Professor Ahmed Jalal Khan Chowdhury
Date Deposited:	29 Nov 2018 15:48
Last Modified:	30 Jan 2019 11:00
URI:	http://irep.iium.edu.my/id/eprint/67808

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