Characterization of a soil-derived bacterial consortium degrading 4-chloroaniline

Abstract

A bacterial consortium comprising four different species was isolated from an Indonesian agricultural soil using a mixture of aniline and 4-chloroaniline (4CA) as principal carbon sources. The four species were identified as Chryseobacterium indologenes SB1, Comamonas testosteroni SB2, Pseudomonas corrugata SB4 and Stenotrophomonas maltophilia SB5. Growth studies on aniline and 4CA as single and mixed substrates demonstrated that the bacteria preferred to grow on and utilize aniline rather than 4CA, although both compounds were eventually depleted from the culture supernatant. However, despite 100 % disappearance of the parent substrates, the degradation of 4CA was always characterized by incomplete dechlorination and 4-chlorocatechol accumulation. This result suggests that further degradation of 4-chlorocatechol may be the rate-limiting step in the metabolism of 4CA by the bacterial consortium. HPLC-UV analysis showed that 4-chlorocatechol was further degraded via an ortho-cleavage pathway by the bacterial consortium. This hypothesis was supported by the results from enzyme assays of the crude cell extract of the consortium revealing catechol 1,2-dioxygenase activity which converted catechol and 4-chlorocatechol to cis,cis-muconic acid and 3-chloro-cis,cis-muconic acid respectively. However, the enzyme had a much higher conversion rate for catechol [156 U (g protein)], indicating preference for non-chlorinated substrates. Members of the bacterial consortium were also characterized individually. All isolates were able to assimilate aniline. P. corrugata SB4 was able to grow on 4CA solely, while S. maltophilia SB5 was able to grow on 4-chlorocatechol. These results suggest that the degradation of 4CA in the presence of aniline by the bacterial consortium was a result of interspecies interactions.

Isolation and characterization of a novel strain of Stenotrophomonas maltophilia possessing various dioxygenases for monocyclic hydrocarbon degradation

“…The pattern generated with API 20NE test was a good match with Xanthomonas maltophilia. Similar results were obtained by Radianingtyas and co-workers (22). These authors identified the particular microorganisms of consortium degrading 4-chloroaniline.…”

Planktonic versus Biofilm Catabolic Communities: Importance of the Biofilm for Species Selection and Pesticide Degradation

“…have not yet proved able to hydrolyze chloropropham, although they are known for their chloroaniline-degrading capacities (10,26,36). Enrichment of the sludge and soil inocula in the presence of a solid matrix led to microbial communities with a higher species richness and evenness.…”

Microbial degradation of 4-chloroaniline by a bacterial consortium

“…Therefore, many efforts have been undertaken to isolate bacteria capable of biodegradation of chloroanilines (Surovtseva et al, 1985;Loidl et al, 1990). Although some microorganisms have been reported to have biodegradability towards chloroanilines, their limitation is that they are unable to grow on chloroanilines as sole sources of carbon and nitrogen Reber et al, 1979;You and Bartha, 1982;Radianingtyas et al, 2003). Only recently, 3-chloroaniline-degrading Comamonas testosteroni strain I2gfp capable of utilizing 3-chloroaniline as a sole source of carbon and nitrogen was isolated (Boon et al, 2000).…”

“…Nonetheless, under certain growth conditions, a few microorganisms have been reported to be able to grow on 4-chloroaniline as a sole carbon and nitrogen source. For instance, previous studies stated that the bacterial isolations were successful only after they were cocul-tivated or induced in the presence of aniline or another cosubstrate, for example, glucose, for some periods of time (Zeyer and Kearney, 1982;Radianingtyas et al, 2003;Travkin et al, 2003). In the current study, we used a defined bacterial consortium, reconstructed from strains isolated from a putatively herbicide-contaminated site, to investigate 4-chloroaniline (4CA) metabolism in the presence of aniline.…”