Aerobic degradation of 2,4,6-trichlorophenol by a microbial consortium - selection and characterization of microbial consortium

Abstract

A microbial consortium that efficiently degrades 2,4,6-TCP (2,4,6-trichlorophenol), as the sole source of carbon and energy under aerobic conditions was selected from municipal activated sludge. Six bacterial strains, designated S(1), S(2), S(3), S(4), S(5) and S(6), were isolated from the selected consortium and five were identified as Sphingomonas paucimobilis (S(2), S(3)), Burkholderia cepacia(S(4)), Chryseomonas luteola (S(5)) and Vibrio metschnikovii (S(6)). After prolonged cultivation followed by successive transfers, the consortium's degradation ability was improved and reached a specific degradation rate of 34 mg 2,4,6-TCP g(-1) dry weight h(-1) (about 51 mg 2,4,6-TCP g(-1) cell protein h(-1)). The soluble chemical oxygen demand, chloride and oxygen uptake balance data clearly indicate the complete dechlorination and mineralization of 2,4,6-TCP. The consortium's activity was not inhibited by 2,4,6-TCP concentrations <or=400 mg l(-1). The highest specific growth rate (micro(max) of 0.01 h(-1)) was achieved at 2,4,6-TCP concentration <or=200 mg l(-1), and the inhibition constant ( K(i)) was 610 mg l(-1) according to the Haldane inhibition kinetic model. An inoculum size up to 120 mg l(-1) cell dry weight is desirable in order to avoid a lag phase and to allow faster degradation of 2,4,6-TCP.

Degradation of 2,4,6-tribromophenol and 2,4,6-trichlorophenol by aerobic heterotrophic bacteria present in psychrophilic lakes

“…The results obtained by HPLC confirmed that after 48 h incubation both 246TCP and 246TBP were completely degraded in all microcosms. A similar result was informed by Kharoune et al (2002) in a bacterial consortioum able to degrade 246TCP. The authors indicated that the consortioum required a 15 day adaptation period to begin degradation, and after successive additions of chlorophenol, the degradation rate increased four times without requiring an adaptation period.…”

“…Due to their constant use, these compounds are common pollutants of soils and freshwater. Fulthorpe and Schofield (1999) reported that microorganisms recently developed the ability to degrade halogenated aromatic compounds as a response to their use as pesticides, even as sole carbon and energy source (Kharoune et al 2002;Sánchez et al 2004;Yamada et al 2008). Nevertheless, several studies have shown that bacteria isolated from environments not exposed to this type of pollutant are able to degrade organochlorinates (Kamagata et al 1997;Sánchez et al 2004).…”

“…The degradation properties of most of the bacteria that have shown the ability to degrade halophenols have been characterized at temperatures between 20 and 30°C (Fulthorpe et al 1996;Kamagata et al 1997;Kharoune et al 2002;Aranda et al 2003;Godoy et al 2003;Matus et al 2003;Sánchez et al 2004). However, little information is available regarding the activity of the aerobic psychrophilic bacteria participating in the metabolism of halophenols such as 246TBP.…”

The Performance of Four Different Mineral Liners on the Transportation of Chlorinated Phenolic Compounds to Groundwater in Landfills

“…Of the four isomers of trichlorophenols investigated in this study (2,4,6-TCP, 2,4,5-TCP, 2,3,6-TCP, and 3,4,5-TCP), the 2,4,5- and 2,4,6-isomers are listed on the US EPA's priority pollutants list. The latter has been included in Directive 76/464/EEC (European Economic Community) as a dangerous substance discharged into the aquatic environment [ 34 , 35 ].…”