Chlorobenzene degradation by Bacillus sp. TAS6CB: A potential candidate to remediate chlorinated hydrocarbon contaminated sites

Abstract

Chlorobenzenes (CB) are very commonly detected in ecosystems notably in the atmosphere, freshwater, sediments, and in urban sewage. They may contaminate ecosystems via the direct discharge of solid and liquid waste or through atmospheric volatilization. In the present study, CB degrading organisms were isolated from contaminated sites and screened for their effectiveness to degrade it. Isolates 6CB efficiently degrade CB. Isolate was identified by 16SrDNA and identified as Bacillus sp. TAS6CB. The cells showed positive chemotaxis towards CB, catechol, and salicylic acid indicates their potential for degradation of xenobiotic compounds. Degradation commence with production of chlorobenzene dioxygenase and further conversion into chlorocatechol, a central intermediate of chlorinated aromatic metabolism. Degradation rates were further enhanced by biosurfactant production as detected and confirmed by TLC analysis. Intermediate metabolites chlorocatechol and cis,cis‐muconic acid, produced during the CB degradation were confirmed by UV scanning, HPLC and GC–MS analysis. Phytotoxicity study showed 40% of phytotoxicity decreased after 48 h of incubation by isolate. Thus, isolate can be used to remediate CB contaminated sites effectively.

Screening of Bacteria for Their Chlorpyrifos Degrading Ability

“…After 7 days incubation growth rate measure at 600 nm on spectrophotometer (Vyas and Murthy, 2015) and chlorpyrifos degradation was measured by the method described by Venugopal et al, (2013). After measurement of growth from test samples, cells were removed by centrifugation and supernatant was used for chlorpyrifos estimation.…”

Exploring Microbes for their Cellulolytic and Lignolytic Enzyme Activity for Manure Preparation

“…DNA from both the isolates was extracted using CTAB method (Murray and Thomson, 1980). The bacterial 16S rRNA gene was amplified from the total genomic DNA using universal eubacteria specific primers viz., 27F and 1541R as described by Vyas and Murthy (2015) which yielded a product of approximately 1500 bp. The PCR conditions were: 35 cycles of 95 °C denaturation for 1 min, annealing at 55 °C for 1 min and extension at 72 °C for 1 min, and final extension at 72 °C for 10 min.…”

A Pandoraea sp. strain efficiently degrades chlorobenzene via monooxygenation pathways with high potential for groundwater bioremediation

“…On the one hand, there is a difference between the culture temperature and the application temperature. The culture temperature in laboratory of the strain is 20-40°C, under which the chlorobenzene-degrading strain can degrade chlorobenzene effectively (Vyas and Murthy 2015). While the actual temperature in groundwater is usually 10-20°C, and these strains don't adapt to the temperature.…”