A novel bacterium that utilizes monochlorobiphenyls and 4-chlorobenzoate as growth substrates

Abstract

A bacterial isolate, tentatively named SK-3, was isolated from tertiary lagoon sludge contaminated with polychlorinated biphenyls for over 25 years. SK-3 was able to grow on 2-chlorobiphenyl, 3-chlorobiphenyl, 4-chlorobiphenyl (4-CB), chloroacetate and 4-chlorobenzoic acid (4-CBA) as sole carbon and energy sources. During growth on 4-CB, a stoichiometric amount of chloride ion was produced and growth yields were comparable to those observed during growth on biphenyl. The production of 4-CBA as a metabolite was not observed. Protein yields during growth on 4-CB and biphenyl suggested that the presence of the chlorine did not impede use of carbons on both aromatic rings. Growth on 4-CBA also resulted in nearly stoichiometric production of chloride ion. Benzoate-grown SK-3 was also able to degrade several Aroclor 1242 congeners without the need for a primary substrate of previous growth on biphenyl.

Characterization of diesel degrading bacterial species from contaminated tropical ecosystem

“…1-5). The observed increase in the OD values and pH was agreeable with the studies on hydrocarbon degradation (Kim and Picardal 2000;Nwinyi et al 2008, Nwinyi 2011. The colour of the enrichment medium changed from yellow to green which could be due to the presence of Pseudomonas sp.…”

“…All the enrichment and degradation experiments were performed using chloride-free minimal salts (MS) medium as described by Kim and Picardal (2000) with slight modification. The medium consisted of (g) 0.5 (NH 4 ) 2 SO 4 , 0.1 MgSO 4 ·7H 2 O, 0.076 Ca (NO 3 ) 2 .4H 2 O and 40 mm phosphate buffer (pH 7.25).…”

Microbial Growth on Dichlorobiphenyls Chlorinated on Both Rings as a Sole Carbon and Energy Source

“…Under anoxic conditions, highly chlorinated congeners can often be reductively dechlorinated (8,25), resulting in congeners that can potentially be degraded by aerobic bacteria. The lightly chlorinated congeners (one to five chlorines) remaining after reductive dechlorination can be either utilized as an aerobic growth substrate (12,16) or cometabolically degraded in the presence of biphenyl (9,14).…”

“…One isolate (SK-3) was selected based on its ability to grow on both 4-chlorobiphenyl and 4-chlorobenzoic acid (4-CBA) (16). Another isolate (SK-4) was ultimately enriched and selected based on an ability to grow on 2,2Ј-CB.…”

“…The CB-degrading bacteria were isolated from PCB-contaminated, tertiary lagoon sludge as previously described (16). One isolate (SK-3) was selected based on its ability to grow on both 4-chlorobiphenyl and 4-chlorobenzoic acid (4-CBA) (16).…”