Chlorinated solvent degradation in groundwater by green rust - bone char composite: solute interactions and chlorinated ethylene competition

Biochar works as a green catalyst for the dechlorination of chlorinated ethylenes (CEs) by green rust (GR). Although the GR-biochar composite shows great potential for groundwater remediation, its performance under...

Distribution of Dehalococcoides 16S rRNA and Dehalogenase Genes in Contaminated Sites

Understanding the spatial distribution of Dehalococcoides and its reductive dehalogenase genes in sediment is important for bioremediation of sites contaminated with chlorinated ethylenes. A total of 56 sediment samples were collected from four contaminated sites in Japan, and quantified copies of Dehalococcoides 16S rRNA and reductive dehalogenase genes: tceA, bvcA, and vcrA, as well as chlorinated ethylenes. Dehalococcoides was detected from 22 sediment samples with various geological formations, textures and saturation conditions. The detected Dehalococcoides 16S rRNA gene ranged from 6.4 × 102 to 2.5 × 107 copies g−1. In the 22 samples, the dehalogenase genes: tceA, bvcA, and vcrA were contained 1.4 × 103 to 1.6 × 104, 1.0 × 103 to 2.0 × 105, and 2.7 × 102 to 8.5 × 105 copies g−1, respectively. Statistical analysis revealed that the distribution of dehalogenase genes depends on site and depth, but not existence of vinyl chloride. To estimate potential for bioremediation of contaminated sites, quantification of dehalogenase genes according to sediment depth is important and thus recommended.

Mechanisms and strategies of microbial cometabolism in the degradation of organic compounds – chlorinated ethylenes as the model

The universal microbial cometabolism provides us with an effective approach to remove man-made xenobiotics. However, the cometabolic bioremediation of toxic organic compounds has not been widely initiated due to the obscure underlying fundamentals in the studies or applications of microbial cometabolism. This review summarizes the current research trends in mechanistic understanding of microbial cometabolism, especially with regard to its potential applications. The crucial factors including key enzyme, enzyme inhibition, toxic effects and energy regulation are discussed, which all significantly contribute to the cometabolic bioremediation of pollutants. The presented review of chlorinated ethylene cometabolism in this overview has further confirmed the fundamentals and hypotheses mentioned above, and thus cometabolism of chlorinated ethylenes has been regarded as a role model of pollution remediation technology using microbial cometabolism. The subsequent prospective research should provide insights into the ambiguous mechanism of microbial cometabolism and help us to develop more efficient bioremediation of progressive pollution.