Tobacco wastes that contain nicotine alkaloids are harmful to human health and the environment. In the investigation, a novel nicotine-biodegrading bacterium TND35 was isolated and identified as Pseudomonas plecoglossicida on the basis of phenotypic, biochemical characteristics and 16S rRNA sequence homology. We have studied the nicotine biodegradation potential of strain TND35 by detecting the intermediate metabolites using an array of approaches such as HPLC, GC-MS, NMR and FT-IR. Biotransformation metabolites, N-methylmyosmine, 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) and other three new intermediate metabolites namely, 3,5-bis (1-methylpyrrolidin-2-yl) pyridine, 2,3-dihydro-1-methyl-5-(pyridin-3-yl)-1H-pyrrol-2-ol and 5-(pyridin-3-yl)-1H-pyrrol-2(3H)-one have been identified. Interestingly, these intermediate metabolites suggest that the strain TND35 employs a novel nicotine biodegradation pathway, which is different from the reported pathways of Aspergillus oryzae 112822, Arthrobacter nicotinovorans pAO1, Agrobacterium tumefaciens S33 and other species of Pseudomonas. The metabolite, HPB reported in this study can also be used as biochemical marker for tobacco related cancer studies.

3‐Nitrotoluene was degraded when incubated with the resting cells of Pseudomonas putida OU83. Most of the 3‐nitrotoluene (70%) was metabolized via reduction of the nitro group to form 3‐aminotoluene (3‐AT). A minor portion (30%) was degraded through a novel pathway involving oxidation of 3‐NT to form 3‐nitrophenol through a series of intermediary metabolites: 3‐nitrobenzyl alcohol, 3‐nitrobenzaldehyde and 3‐nitrobenzoic acid. Degradation of 3‐nitrophenol occurred with the formation of a transient intermediary metabolite, hydroxynitroquinone, which was further degraded with the near stoichiometric release of nitrite into the medium. 3‐Nitrotoluene‐induced cells showed increased oxygen consumption with 3‐nitrotoluene, 3‐nitrobenzaldehyde, 3‐nitrobenzoate, and 3‐nitrophenol as substrates in comparison to uninduced cells. Cell extracts prepared from strain OU83 contained benzylalcohol dehydrogenase and benzaldehyde dehydrogenase activities. The experimental evidence suggests a novel pathway for the degradation of 3‐NT in which C‐1 elimination is catalyzed by a cofactor‐independent deformylase, rather than a decarboxylase or dioxygenase.

The soluble methane monooxygenase (sMMO) enzyme complex of methanotrophs cometabolizes haloaliphatic compounds such as trichloroethylene. Two 18-mer oligonucleotides as primary primers and a nested primer of the same length were selected to amplify specific DNA sequences of the sMMO gene cluster using polymerase chain reaction (PCR). Two DNA fragments of sizes 270 and 400 base pairs were obtained when purified DNA from the methanotroph Methylosinus trichosporium OB3b was used as template. The primers were specific for sMMO sequences of M. trichosporium, since none of the 13 bacterial isolates screened yielded the expected length of PCR-amplified DNA fragments. The detection limit of the PCR method was 5 x 10(2) cells of M. trichosporium. The sMMO sequences were successfully amplified in groundwater (containing native microbial population) when seeded with M. trichosporium, FP1 sense (5'-ATGTCCAGCGCTCATAAC-3'), RP1 antisense (5'-TCAGATGTCGGTCAGGGC-3'), FP2 sense nested (5'GCCATCATCGGTCAGGGC-3'), and FP2 sense nested (5'-GCCATCATCGAGGACATC-3').

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