Isolation and Characterization of a Novel Bacterium from the Marine Environment for Trichloroacetic Acid Bioremediation

Abstract

<jats:p>Halogenated compounds are an important class of environmental pollutants that are widely used in industrial chemicals such as solvents, herbicides, and pesticides. Many studies have been carried out to explore the biodegradation of these chemicals. Trichloroacetic acid (TCA) is one of the main halogenated compounds that are carcinogenic to humans and animals. The bacterium was isolated from the northern coastline of Johor Strait. In this study, the ability of strain MH2 to biodegrade TCA was evaluated by a growth experiment and dehalogenase enzyme assay. The growth profile of the isolated strain was examined. The doubling time for L. boronitolerans MH2 was found to be 32 h. The release of chloride ion in the degradation process was measured at 0.33 × 10−3 ± 0.03 mol∙L−1 after 96 h when the growth curve had reached its maximum within the late bacterial exponential phase. The results showed that the strain had a promising ability to degrade TCA by producing dehalogenase enzyme when cell-free extracts were prepared from growth on TCA as the sole carbon source with enzyme-specific activity, 1.1 ± 0.05 µmolCl−min−1∙mg−1 protein. Furthermore, the morphological, and biochemical aspects of the isolated bacterium were studied to identify and characterize the strain. The morphological observation of the isolated bacterium was seen to be a rod-shaped, Gram-positive, motile, heterotrophic, and spore-forming bacterium. The amplification of the 16S rRNA and gene analysis results indicated that the isolated bacterium had 98% similarity to Lysinibacillus boronitolerans. The morphological and biochemical tests supported the 16S rRNA gene amplification. To the best of the authors’ knowledge, this is the first reported case of this genus of bacteria to degrade this type of halogenated compound.</jats:p>

Functional profiling of bacterial communities in Lake Tuz using 16S rRNA gene sequences

“…The most abundant phyla were Firmicutes, Fusobacteria and Proteobacteria, and we predicted functional genes related to evolutionary adaptability and the potential for bioremediation. Our results will support future research on bioremediation carried out by potential resident microbes that produce previously unknown enzymes-for instance, new types of dehalogenases [16][17][18][19] We note that detailed information on microbial communities is necessary for judging the biotechnological potential of individual bacterial species.…”

Improving ‘Lipid Productivity’ in Microalgae by Bilateral Enhancement of Biomass and Lipid Contents: A Review

“…Genetic engineering has previously presented a promising approach for research in different scientific areas [30][31][32][33]. As is the case in other research fields, genetic engineering provides an alternative approach to bypass the controversial relationships between lipid accumulation and cell growth [34].…”

Isolation of Klebsiella pneumoniae from Sungai Skudai and in silico analysis of putative dehalogenase protein

“…A total of 0.5 L of stock solution of "Paul John Chapman" or 10× PJC basal salts (containing 16.22 g K2HPO4, 5.0 g NaH2PO4•2H2O and 12.5 g (NH4)2SO4) and 10× PJC trace metals (containing 0.5 g nitrilotriacetic acid, 1.0 g MgSO4•7H2O, 0.06 g FeSO4•7H2O, 0.015 g MnSO4•4H2O and 0.015 g ZnSO4•H2O) were prepared (Hareland et al, 1975;Heidarrezaei et al, 2020). The growth media contained 10 mL of 10× basal salts and 10 mL of 10× trace metals per 100 mL of distilled water and were autoclaved at 121 °C for 5 min, 15 psi.…”

“…Recently, microbial degradation of toxic compounds has become a prominent path to transform toxic compounds into harmless products. A large number of dehalogenases producing bacteria have been previously isolated, purified and characterized by widely distributed microorganisms that utilize halogenated compounds as their primary sources of carbon and energy (Ismail et al, 2016;Heidarrezaei et al, 2020;Oyewusi et al, 2020;Wahhab et al, 2021). The enzyme possessed by the microbes to detoxify harmful halogenated compounds has also been well studied (Huyop and Nemati, 2010;Hamid et al, 2011;Adamu et al, 2020).…”