Description:
g-Hexachlorocyclohexane (g-HCH, BHC, lindane) is a halogenated organic insecticide that has been used worldwide for agriculture and public health. Because of its high toxicity and persistence in soil, the use of g-HCH has been prohibited in many countries. g-HCH is degraded rapidly under anaerobic conditions, but is considered extremely persistent in upland soil. Sphingomonas (formerly Pseudomonas) paucimobilis SS86 was isolated from an upland experimental field to which g-HCH was applied once a year for twelve years. The mutant of the strain SS86, named UT26, has nalidixic acid resistance as a genetic marker and utilizes g-HCH as a sole source of carbon and energy under aerobic conditions. The genes and enzymes involved in the g-HCH degradation pathway of S. paucimobilis UT26 have been investigated (Imai et al., 1991; Nagata et al., 1999, J. Ind. Microbiol. Biotechnol. 23: 380-390). The cyanobacteria Anabeana sp. PCC7120 and Nostoc ellipsosporum have also been shown to metabolize lindane. A mixture of 1,2,4- and 1,2,3-trichlorobenzenes is produced ([http://www.ncbi.nlm.nih.gov/pubmed/7534052|Kuritz and Wolk, 1995]). The absolute configuration of 2,4,5-Trichloro-2,5-cyclohexadiene-1-ol and 2,5-Dichloro-2,5-cyclohexadiene-1,4-diol have not yet been determined. The biodegradation pathway for beta-hexachlorocyclohexane is found elsewhere.