Degradation of halogenated compounds by haloalkane dehalogenase DadA from Alcanivorax dieselolei B-5

Abstract:

Abstract:［Objective］Alcanivorax dieselolei B-5 is an important oil-degrading bacterium．We studied its substrate range and degradation of halogenated compounds．［Methods］Growth capability of B-5 was examined with different halogenated substrates as sole carbon source．A putative haloalkane dehalogenase (HLD) gene named dadA was found from the genome of strain B-5 and analyzed by sequence alignment，phylogenetic analysis and homologous modeling．After heterologous expression in Escherichia coli and purification，the activity of DadA towards 46 substrates was determined．［Results］Strain B-5 was capable of utilizing various halogenated compounds (C3 -C18) as the sole carbon source．DadA had typical catalytic pentad residues of HLD-II subfamily，but it was independent from other members of this subfamily according to phylogenetic analysis． Activity assay showed that DadA has higher specificity and narrower substrate range than other characterized HLDs and it only showed activity toward 1，2，3-tribromopropane，1，2-dibromo-3-chloropropane and 2，3-dichloroprop-1-ene among 46 tested substrates．［Conclusions］ Strain B-5 and its HLD DadA can degrade halogenated aliphatic pollutants although．