Biodechlorination of Chlorinated Aliphatic Compounds ‎Trichloroethylene, Dichloromethane, and Dichloroethane in ‎Aqueous Solution, Using Aerobic Sphingopyxix ummariensis ‎Bacteria

The chlorinated organic compounds are the most dangerous water pollutants in industrial sites. The aim of this study was to investigate the biodechlorination of chlorinated aliphatic compounds; trichloroethylene, dichloromethane, and 1,2- dichloroethane in aqueous solution, using aerobic Sphingopyxix ummariensis bacteria. In this experimental study, aliphatic chlorinated compounds; diclormethan, trichlorethylene, and 1,2-dichloroethane with purity of 99.9% were used. A visible-ultraviolet spectroscopy was used to determine the cell growth from measuring the turbidity of the medium at 600nm. The amount of released chloride was measured by an Ion Selective Electrode (ISE). The live bacterial sample was inoculated into the Nutrient Broth medium and was incubated at 30°C and 150rpm for 24 hours. The rate of dechlorination of diclormethan, trichlorethylene, and 1,2-dichloroethane by Sphingopyxis ummariensis were measured as 1.3, 1.05, and 0.63mg/l.h, respectively. The addition of glucose and yeast extract, as co-substrate, led to an increase in the cell growth and dechlorination rate up to 3.28, 1.67 and 0.90mg/l.h, respectively. During experiment, the highest dechlorination was measured at concentration of 2.5mM, at exponential growth phase. Sphingopyxix ummariensis bacteria is capable of biodechlorination of chlorinated aliphatic compounds and can grows on trichloroethylene, dichloromethane, and 1,2-dichloroethane as a single carbon source and can decolorize them. This strain has the highest growth and removal efficiency in eliminating dichloromethane as the sole source of carbon along with glucose and yeast extract as co-substrate.