Anaerobic Degradation of Lindane and Other HCH Isomers

Evaluating degradation of hexachlorcyclohexane (HCH) isomers within a contaminated aquifer using compound-specific stable carbon isotope analysis (CSIA)

“…Thus, it can be inferred that d-HCH was the most recalcitrant HCH isomer with respect to calculated biodegradation rate constants and half-life values (Table 1). A high recalcitrance of d-HCH under anoxic conditions has also been suggested in other studies (Lal et al, 2010;Mehboob et al, 2013).…”

“…Biodegradation is a sustainable removal process of HCHs in the subsurface (Bhatt et al, 2009) and a cost efficient alternative to physico-chemical remediation of HCH contaminated groundwater and soils (Alvarez et al, 2012;Langenhoff et al, 2013;Phillips et al, 2006). The molecular structure of the HCH isomers plays a key role in biodegradation as it has been shown that a and g isomers are degraded faster than b and d isomers (Lal et al, 2010;Mehboob et al, 2013). However, concentration-based assessment of in situ pollutant biodegradation within contaminated aquifers is limited, because the concentration of contaminants can also be significantly decreased by physical processes like volatilization, sorption, dilution and dispersion.…”

Genetic Analysis of Citrobacter sp.86 Reveals Involvement of Corrinoids in Chlordecone and Lindane Biotransformations

“…Finally, we postulate that the implication of corrinoids, synthesized by Citrobacter sp.86, in lindane dechlorination as shown in this study could be extended not only to C. freundii but also to other bacteria that anaerobically degrade lindane such as D. gigas , D. multivorans , and Clostridium ( Macrae et al, 1969 ; Jagnow et al, 1977 ; Ohisa and Yamaguchi, 1978 ; Boyle et al, 1999 ; Badea et al, 2009 ; Mehboob et al, 2013 ). In the same way, corrinoids could be involved in lindane degradation by consortia with the enrichment of Pelobacter within the dehalogenation process ( Qiao et al, 2020 ).…”

“…Citrobacter sp.86 is a facultative anaerobe, but its genome does not encode homologs of the lin genes. Co-metabolic anaerobic degradation of lindane was reported for facultative anaerobic bacteria like C. freundii ( Jagnow et al, 1977 ) but also for strict anaerobes like a Clostridium sp., Desulfovibrio gigas and Desulfococcus multivorans ( Macrae et al, 1969 ; Ohisa and Yamaguchi, 1978 ; Boyle et al, 1999 ; Badea et al, 2009 ; Mehboob et al, 2013 ), in bacterial consortia ( Qiao et al, 2020 ; Zhang et al, 2020 ) and finally using slurry systems ( Quintero et al, 2005 ; Robles-González et al, 2008 ; Camacho-Pérez et al, 2012 ). In 2011, an anaerobic enrichment culture was showed to use lindane as electron acceptor; however, no organohalide-respiring bacteria were detected in the consortium ( Elango et al, 2011 ).…”

Compound-Specific Stable Isotope Analysis: Implications in Hexachlorocyclohexane in-vitro and Field Assessment

“…Figure S1 symbolizes the major intermediates from the aerobic degradation of c-HCH. In the environment it is these intermediates along with the HCH substrates that aid in tracing the prominent active pathways.Cell suspensions of different sulfate reducing bacteria has been reported with ability to dehalogenate c-HCH [9,46]. Anaerobic transformation reactions in sludge and soils have been revealed to dehalogenate a-, b-, cand d-HCH to chlorobenzene and benzene.…”