Screening of Multi-metal Resistances in a Bacterial Population Isolated from Coral Tissues of Central Java Coastal Waters, Indonesia

Abstract

Scleractinian corals harbor diverse bacterial communities within their tissue. However, it is still not known the significant role of those bacteria in bioremediation of heavy metal contamination. The present study aimed to investigate the diversity of the bacterial eommumty associated with the corals that have multiple resistance to heavy metals. Sixty-one coral bacteria isolated from three different life-forms of scleractinian coral samples collected from Central Java coastal wTaters were established by plating on ZobelLs 2214E. Those isolates were screened for their resistance against Pb, Cr, Zn, at 1 mM level using agar diffusion method and 22 isolates were selected. Minimal Inhibitory Concentrations (MIC) of heavy metals were determined and different MIC of these isolates was shown to be highly resistant to Pb, Cr and Zn ions. A rapid grouping by using Repetitive Extragenic Palindromic (REP)-PCR was conducted to estimate the richness of the isolates. Three heavy metal resistant bacterial strains representing three major genetic groups were selected for further studies. Based on analysis of morphological, biochemical and 16S rDNA sequence of these isolates revealed that one strain belongs to y-proteobacteria division while the other two belong to Firmicutes division. Isolate PL05 was closely related to Pseudoalteromonas sp. while PL12 and PL22 isolates were closely related to Virgibacillus sp. This work provides the first evidence of bacteria possessing multiple resistances against heavy metals can be recovered from corals.