Biodegradation of monochloroacetic acid used as a sole carbon and energy source by Xanthobacter autotrophicus GJ10 strain in batch and continuous culture

Organohalogen compounds, widely used as pes cides in agriculture and solvents in the industrial sector, cause environmental pollu on and health problems due to their toxicity and persistence. Numerous studies have been conducted on the biodegrada on of organohalogen compounds, with many focusing on the use of dehalogenase from bacteria. Haloacid dehalogenase is a group of enzymes that cleaves the carbon-halogen bond in halogenated alipha c acids. In a previous study, the bcfd1 gene encoded haloacid dehalogenase from Bacillus cereus IndB1 was successfully isolated and characterized. This research aimed to create an expression system of the bcfd1 gene by subcloning this gene into pET expression vector and to overexpress the gene in Escherichia coli BL21 (DE3). In addi on, the recombinant protein was characterized to gain a be er understanding of the cataly c ac on of this enzyme. A high expression of bcfd1 was obtained by inducing the culture at OD 550 0.8-1.0 using 0.01 mM IPTG as determined by SDS-PAGE. Zymogram analysis proved that the recombinant protein possessed dehalogenase ac vity. Bcfd1 ac vity toward monochloroace c acid (MCA) showed specific ac vity of 37 U/mg at 30°C, pH 9. The predicted ter ary structure of Bcfd1 was es mated has conserved α/ß hydrolase folding mo f for haloacid dehalogenase superfamily.

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“…(Olaniran et al 2004), Xanthobacter sp. (Torz and Beschkov 2005), and Rhodobacteraceae sp. (Novak et al 2013).…”

Section: Introduc Onmentioning

confidence: 99%

Cloning and expression of haloacid dehalogenase gene from Bacillus cereus IndB1

Ratnaningsih

Idris²

2018

Indones. J. Biotechnol.

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“…Similarly, bromoacetic acid is hydrolyzed by haloacid dehalogenase, but it is toxic to the wild-type strain GJ10 (van der Ploeg et al 1995). On the other hand, we recently demonstrated the biodegradation of monochloroacetate by strain GJ10 (Torz & Beschkov 2005), although earlier reports did not suggest such possibility.…”

Section: Introductionmentioning

confidence: 67%

Metabolism of mono- and dihalogenated C1 and C2 compounds by Xanthobacter autotrophicus growing on 1,2-dichloroethane

et al. 2006

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The conversion of and toxic effects exerted by several mono- and dihalogenated C1 and C2 compounds on cultures of Xanthobacter autotrophicus GJ10 growing on 1,2-dichloroethane were investigated. Bromochloromethane, dibromomethane and 1-bromo-2-chloroethane were utilized by strain GJ10 in batch culture as a cosubstrate and sole carbon source. The rate of degradation of dihalomethanes by whole cells was lower than that of 1,2-dichloroethane, but a significant increase of the rate of dihalomethane biodegradation was observed when methanol or ethanol were added as a cosubstrate. Products of the degradation of several tested compounds by haloalkane dehalogenase were analyzed and a new metabolic pathway based on hydrolytic conversion to formaldehyde was proposed for the dihalomethanes. Strain GJ10 growing on 1,2-dichloroethane converted 2-fluoroethanol and 1-chloro-2-fluoroethane to 2-fluoroacetate, which was tolerated up to a concentration of 2.5 mM. On the basis of the results from batch cultures an inert (dichloromethane), a growth-supporting (dibromomethane) and a toxic (1,2-dibromoethane) compound were selected for testing their effects on a continuous culture of strain GJ10 growing on 1,2-dichloroethane. The compounds were added as pulses to a steady-state chemostat and the response of the culture was followed. The effects varied from a temporary decrease in cell density for dibromomethane to severe toxicity and culture washout with 1,2-dibromoethane. Our results extend the spectrum of halogenated C1 and C2 compounds that are known to be degraded by strain GJ10 and provide information on toxic effects and transformation of compounds not serving as a carbon source for this bacterium.

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“…Biodegradation of MCA by the strain is confirmed by M. Torz and V. Beschkov (7), investigating the influence of different carbon substrates of inoculum in batch and continuous processes.…”

Section: Introductionmentioning

confidence: 81%