Advances of using Dehalogenimonas in anaerobic degradation of chlorinated compounds and bioremediation of contaminated sites / 生物工程学报

The genus Dehalogenimonas (Dhgm) is a recently discovered taxonomic group within the class Dehalococcoidia of the phylum Chloroflexi. To date, Dhgm consists of three formally described species including Dehalogenimonas lykanthroporepellens, Dehalogenimonas alkenigignens and Dehalogenimonas formicexedens. All isolates of these three Dhgm species are obligate organohalide-respiring bacteria. They use hydrogen and formate as electron donors and chlorinated ethanes (e.g., 1,2,3-trichloropropane, 1,2-dichloropropane, 1,2-dichloroethane) as electron acceptors in energy-conserving reductive dechlorination reaction. Chlorinated ethanes are common groundwater contaminants in China. The unique metabolic capacities of Dhgm strains implicate it may play important roles in site remediation. The recently reported Dhgm sp. strain WBC-2 and 'Candidatus Dehalogenimonas etheniformans' strain GP are capable of dechlorinating certain chlorinated ethenes. More importantly, strain GP can completely detoxify the carcinogenic vinyl chloride (VC) to ethene. These findings expand the diversity of microorganisms involved in the respiratory VC reductive dechlorination and improve the understanding of Dhgm's ecological functions. Here, we summarize the advances in physiological and biochemical characteristics, ecological functions and genomic features of Dhgm, with the aim to develop effective and sustainable strategies to facilitate the bioremediation of chlorinated compounds contaminated sites.

Dominant bacterial and archaeal phyla associated with top soils sourced from commercial farm holding in Delta State, Nigeria

ABSTRACT: The dominant bacteriological and archaeal phyla of compounded soils sourced from a commercial farm estate located in Amukpe town and a nearby control in Adavware community both in Delta State, were evaluated with the aid of Next Generation Sequencing (NGS) protocols. The residual herbicide and pesticide composition of the bulked soils were also determined using gas chromatography (GC) and electron capture detector (ECD). Total concentrations of the extracted DNA were 6.83 and 6.65 ng/µl for the control and experimental soils. Nine (9) bacterial phyla; Proteobacteria, Actinobacteria, Chloroflexi, Firmicutes, Verrucomicrobia, Planctomycetes, Bacteroidetes Acidobacteria, and Elusimicrobia were observed in the control soil. Thirteen (13) bacterial phyla; Elusimicrobia, Fibrobacteres Lentisphaerae, Armatimonadetes, Cyanobacteria/Chloroplast, Bacteroidetes, Actinobacteria, Proteobacteria, Chloroflexi, Firmicutes, Acidobacteria, Planctomycetes and Verrucomicrobia were detected in the experimental soil. Two (2) archaeal phyla; Euryarchaeota, and Diapherotrites were detected both the experimental and control soil, whilst an additional archaeal phylum; Woesearchaeota was present in only the experimental soil. The total organochloride phosphate component of the experimental soil was 1.4µg/Kg and 0.4µg/Kg for the control soil respectively