ABSTRACT
A bacterium Stenotrophomonas sp. TRMK2 capable of utilizing cinnamic acid was isolated from agro-industrial waste by enrichment culture technique. This strain completely utilizes 5 mM cinnamic acid within 18 h of incubation. The different metabolites formed during the degradation of cinnamic acid were characterized by GC-HRMS. The involvement of various enzymes, namely cinnamate reductase, 3-phenylpropionic acid hydroxylase, p-hydroxybenzoic acid hydroxylase and protocatechuate 3,4-dioxygenase in cinnamic acid degradation was demonstrated. A catabolic pathway for cinnamic acid in Stenotrophomonas sp. TRMK2 is as follows: Cinnamic acid; 3-Phenylpropionic acid; 3-(4-Hydroxyphenyl) propionic acid; 4-Hydroxy benzoic acid and Protocatechuic acid. Further, this strain is capable of utilizing various phenolic compounds.
ABSTRACT
A high-efficiency fluoranthene-degrading bacterium Paenibacillus sp. PRNK-6 was isolated from PAH-contaminated soil. The strain degrades 96% (240 mg l-1) of fluoranthene in 48 h. Various metabolic intermediates of fluoranthene catabolism were identified by gas chromatography (GC) and gas chromatography-high resolution mass spectrometry (GC-HRMS). Metabolite characterization, metabolite-feeding experiments, and appropriate enzyme activities in the cell-free extracts suggest the existence of a bifurcated pathway down the phthalic acid for complete mineralization of fluoranthene in PRNK-6. In this strain, fluoranthene catabolism begins by the attack on the fused aromatic ring portion of fluoranthene. Two terminal aromatic metabolites protocatechuate and catechol undergo ring cleavage by protocatechuate 3,4-dioxygenase and catechol 1,2-dioxygenase, respectively, and enter the central metabolism.
Subject(s)
Fluorenes/metabolism , Paenibacillus/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Biodegradation, Environmental , Dioxygenases/genetics , Dioxygenases/metabolism , Gas Chromatography-Mass Spectrometry , Paenibacillus/classification , Paenibacillus/genetics , Paenibacillus/isolation & purification , Phthalic Acids/metabolism , Soil Microbiology , Soil Pollutants/metabolismABSTRACT
A nitrile utilizing bacterium Rhodococcus sp. MTB5 was previously isolated in our laboratory by the enrichment culture technique. It is able to utilize butyronitrile as sole carbon, nitrogen, and energy source. Maximum butyronitrile degrading property of this strain has been investigated. Results reveal that 100, 98, and 88 % degradation was achieved for 2, 2.5, and 3 % butyronitrile, respectively. The strain is capable of growing in as high as 5 % butyronitrile concentration. A two-step pathway involving nitrile hydratase (NHase) and amidase was observed for the biodegradation of butyronitrile. Complete degradation (mineralization) of butyronitrile with the help of metabolite feeding experiment was reported. The significance of this investigation was the capability of the strain to completely degrade and its ability to grow on higher concentrations of butyronitrile. These potential features make it a suitable candidate for practical field application for effective in situ bioremediation of butyronitrile contaminated sites.
