Identification and Characterization of a 2,2-Dichloropropionic Acid (2,2-DCP) Degrading Alkalotorelant Bacterium Strain BHS1 Isolated from Blue Lake, Turkey

Abstract

An acid, 2,2-dichloropropionic acid (2,2-DCP) is an active ingredient in herbicide (Dalapon®). Using 2,2-DCP as a model substrate, an alkalotolerant bacterium was successfully isolated from the Blue Lake, Turkey. This bacterium is a potential bioremediation agent of recalcitrant xenobiotic halogenated compounds. This study aimed to prove the efficacy of the alkalotolerance Bacillus megaterium BHS1 in degrading 2,2-DCP as the sole source of carbon. Biolog GEN III system and 16S rRNA analysis were used for the identification of the bacterium. It was discovered that the strain BHS1 is Bacillus megaterium, and the bacterium that was observed to thrive in alkaline conditions (pH 7.0−14.0), supplemented with varying concentrations of 2,2-DCP (from 20 to 60 mM). Growth of strain BHS1 was exceptional in 40 mM of 2,2-DCP at pH 9, corresponding to a cell doubling time of 17.7 hour, whereas was fully inhibited at 50 mM 2,2-DCP. Since halogenated pollutants can make their way into highly alkaline environments, therefore, identifying threshold levels of strain BHS1 with respect to alkaline-tolerance and maximum level of 2,2-DCP may prove pertinent. This is to ensure that an optimal environment is created for the bacteria to degrade 2,2-DCP-contaminated water. In addition, this is the first study exploring a Bacillus species isolated from an alkaline environment adept in utilizing 2,2-DCP as a sole source of carbon. Hence, the ability of this strain to degrade other types of haloalkanoic acids constitutes a worthy future study.

Comparative modeling and enzymatic affinity of novel haloacid dehalogenase from Bacillus megaterium strain BHS1 isolated from alkaline Blue Lake in Turkey

“…Bacillus megaterium strain BHS1 produces dehalogenases owing to its ability to grow on a minimal medium containing 2,2-DCP as the primary carbon source [27]. The genomic analysis of a functional haloacid degrading gene in Bacillus megaterium strain BHS1 was performed from its full genome sequence [26].…”

Genomic analysis of a functional haloacid-degrading gene of Bacillus megaterium strain BHS1 isolated from Blue Lake (Mavi Gölü, Turkey)

“…Whole-cell analysis of maximum chloride released from 2,2DCP, D,L-2-chloropropionic acid (D,L-2CP), L-2chloropropionic acid (L-2CP), and D-2CP B. megaterium BHS1 was incubated with individual selected substrates (2,2-DCP, D,L-2CP, L-2CP, and D-2CP) under specific growth conditions as previously described (Wahhab et al 2020). A pure grade of the substrates above were purchased from Sigma-Aldrich or Merck (USA).…”

“…The general features of strain BHS1 have been described by Wahhab et al (2020). Its full 16S rRNA gene sequence was deposited in GenBank under accession number MT883351.…”

“…The germane finding of the genomic annotation for strain BHS1 was the identification of a metabolic pathway that includes two dehalogenase families that were inferred based on the ability of the cells to optimally grow on minimal medium containing 2,2-DCP as the sole carbon source, as reported by Wahhab et al (2020).…”

“…Because BHS1 produces a dehalogenase, it can utilize 2,2-dichloropropionic acid (2,2DCP) as a sole carbon source (Wahhab et al 2020). Therefore, we sequenced the genome of strain BHS1 to understand the regulatory mechanisms for overexpression of dehalogenase genes and how dehalogenases contribute to BHS1 survival in an alkali-laden ecosystem.…”