Sulfate-reducing bacteria (SRB) pose a serious problem to offshore oil industries by producing su... more Sulfate-reducing bacteria (SRB) pose a serious problem to offshore oil industries by producing sulfide, which is highly reactive, corrosive and toxic. The dissimilatory sulfite reductase (dsr) gene encodes for enzyme dissimilatory sulfite reductase and catalyzes the conversion of sulfite to sulfide. Because this gene is required by all sulfate reducers, it is a potential candidate as a functional marker. Denaturing gradient gel electrophoresis fingerprints revealed the presence of considerable genetic diversity in the DNA extracts achieved from production water collected from various oil fields. A quantitative PCR (qPCR) assay was developed for rapid and accurate detection of dsrB in oil field samples. A standard curve was prepared based on a plasmid containing the appropriate dsrB fragment from Desulfomicrobium norvegicum. The quantification range of this assay was six orders of magnitude, from 4.5 10 to 4.5 10 copies per reaction. The assay was not influenced by the presence of fo...
An improved method for simultaneous analysis of fermentative products and separation of acetone a... more An improved method for simultaneous analysis of fermentative products and separation of acetone and butyric acid using flow programming in HPLC.
International Biodeterioration & Biodegradation, 2014
ABSTRACT India is rich in coal bed methane resources but still lacks in methane development techn... more ABSTRACT India is rich in coal bed methane resources but still lacks in methane development technologies. To begin understanding this prospective source, in the present investigation, microbial methane production was examined from bituminous, subbituminous and lignite coals obtained from Jharia coal mines in India. Microbial populations were enriched over a period of 21 days on various methanogenic specific substrates including the three ranks of coal. Maximum methane production (49%) was obtained on Methanosprillium sp specific medium (sodium acetate and isopropanol) supplemented with subbituminous coal at 65 °C and pH 6.8. Phylogenetic analysis of 16S rRNA gene sequences from the selected CBM65 consortium revealed a syntrophic association between a hydrogenotrophic methanogen Methanoculleus thermophiles and fermentative bacteria Comamonas sp. This is the first report of methane production by a consortium enriched from Indian coal bed methane reservoirs at such high temperature. The results of this study shed light on the fact that Jharia coal mines are methanogenically active and offer a prospective source for coal bed methane extraction. It is also, considered as the richest source of methane in India further this data will help in determining the potential role of methane emitted from this site in influencing the global carbon cycle.
To compare few phenotypic and genotypic characteristics of two desulfurizing bacterial strains, M... more To compare few phenotypic and genotypic characteristics of two desulfurizing bacterial strains, Mycobacterium phlei SM120-1 and Mycobacterium phlei GTIS10. In the present study, dibenzothiophene (DBT) desulfurizing activity, composition of fatty acids of cell membranes, DBT sulfone monoxygenase gene (bdsA) and the selection pressure applied during the growth and enrichment of the bacterial strains M. phlei SM120-1 and M. phlei GTIS10 were compared in our laboratory. The DBT desulfurization activity of M. phlei SM120-1 was found to be 0.17 +/- 0.02 micromol 2-HBP min(-1) (gram dry cell weight)(-1) and that of the bacterial strain M. phlei GTIS10 was 1.09 +/- 0.05 micromol 2-HBP min(-1) (gram dry cell weight)(-1). Fatty acid methyl ester analysis of cell membranes of these two bacterial strains in the presence of light gas oil showed that both the strains had different fatty acid profiles in their cell membranes. Comparison of the full gene sequences of the desulfurization gene bdsA in the two bacterial strains showed significant difference in the bdsA gene sequences. There was a significant difference observed in the selection pressure applied during the growth and enrichment of the two bacterial strains. The results of the comparative study of the bacterial strains, M. phlei SM120-1 and M. phlei GTIS10 showed that there were considerable differences in the phenotypic and genotypic characteristics of these two strains. The present study would broaden the understanding of biodesulfurization trait at intra-species level.
Sulfate-reducing bacteria (SRB) developed biocathodes efficient for reduction of acetic and butyr... more Sulfate-reducing bacteria (SRB) developed biocathodes efficient for reduction of acetic and butyric acids to alcohols and acetone via direct electron transfer reaching current densities of 160-210 A m(-2).
A newly discovered enteric bacterium Leclercia adecarboxylata PS4040, isolated from oily sludge c... more A newly discovered enteric bacterium Leclercia adecarboxylata PS4040, isolated from oily sludge contaminated soil sample was reported for degradation of polycyclic aromatic hydrocarbons (Appl Environ Microbiol 70:3163-3166, 2004a). This strain could degrade 61.5% of pyrene within 20 days when used as sole source of carbon and energy. The time course degradation experiment detected several intermediate products and the metabolites were identified by gas chromatography mass spectrometry analysis. Metabolite I was the detected on the 5th day and was identified as 1-hydroxypyrene and was detected till 10th day. Metabolite II which was detected on 10th day was identified as 1,2-phenanthrenedicarboxylic acid. Metabolite III and Metabolite IV were identified as 2-carboxy benzaldehyde and ortho-phthalic acid, respectively and were detected in the culture broth on 10th and 15th day. 1,2-benzene diol (catechol) was the fifth metabolite detected in the culture extracts on the 15th day and was subsequently reduced on day 20. Identification of Metabolite I as 1-hydroxypyrene was further investigated as this intermediate was not previously reported as a ring oxidation product for degradation of pyrene by bacterial strains. Purification by preparative high performance liquid chromatography and nuclear magnetic resonance spectroscopy, confirmed the identification of Metabolite I as 1-hydroxypyrene. L. adecarboxylata PS4040 could also use 1-hydroxypyrene as a sole source of carbon and energy. Thus a probable pathway for degradation of pyrene by enteric bacterium is proposed in this study, with 1-hydroxypyrene as initial ring oxidation product.
The diversity among a set of bacterial strains that have the capacity to degrade total petroleum ... more The diversity among a set of bacterial strains that have the capacity to degrade total petroleum hydrocarbons (TPH) in soil contaminated with oily sludge (hazardous hydrocarbon waste from oil refineries) was determined. TPH is composed of alkane, aromatics, nitrogen-, sulfur-, and oxygen-containing compound, and asphaltene fractions of crude oil. The 150 bacterial isolates which could degrade TPH were isolated from soil samples obtained from diverse geoclimatic regions of India. All the isolates were biochemically characterized and identified with a Biolog microbial identification system and by 16S rDNA sequencing. Pseudomonas citronellolis predominated among the 150 isolates obtained from six different geographically diverse samplings. Of the isolates, 29 strains of P. citronellolis were selected for evaluating their genetic diversity. This was performed by molecular typing with repetitive sequence (Rep)-based PCR with primer sets ERIC (enterobacterial repetitive intergenic consens...
Biofuels Bioethanol production from lignocellulosics: an overview Bioethanol: a status review on ... more Biofuels Bioethanol production from lignocellulosics: an overview Bioethanol: a status review on metabolic pathway modification of certain ethanologenic bacteria through genetic engineering Bioethanol production technologies: economics, environmental impact, and policy Bio-hydrogen: applications and future prospects Methanogenesis from agro-industrial residues: potential and prospects Biomass- gasifier-based power plants: potential, problems and research needs for decentralized rural electrification Industrial solid waste Coal bed methane Bioreactors for waste water treatment Ceramic membrane filters from waste fly ash and their applications Technological options for municipal solid waste management Technological trends and opportunities in cogeneration Environmental regulations in India for waste management
Sulfate-reducing bacteria (SRB) pose a serious problem to offshore oil industries by producing su... more Sulfate-reducing bacteria (SRB) pose a serious problem to offshore oil industries by producing sulfide, which is highly reactive, corrosive and toxic. The dissimilatory sulfite reductase (dsr) gene encodes for enzyme dissimilatory sulfite reductase and catalyzes the conversion of sulfite to sulfide. Because this gene is required by all sulfate reducers, it is a potential candidate as a functional marker. Denaturing gradient gel electrophoresis fingerprints revealed the presence of considerable genetic diversity in the DNA extracts achieved from production water collected from various oil fields. A quantitative PCR (qPCR) assay was developed for rapid and accurate detection of dsrB in oil field samples. A standard curve was prepared based on a plasmid containing the appropriate dsrB fragment from Desulfomicrobium norvegicum. The quantification range of this assay was six orders of magnitude, from 4.5 10 to 4.5 10 copies per reaction. The assay was not influenced by the presence of fo...
An improved method for simultaneous analysis of fermentative products and separation of acetone a... more An improved method for simultaneous analysis of fermentative products and separation of acetone and butyric acid using flow programming in HPLC.
International Biodeterioration & Biodegradation, 2014
ABSTRACT India is rich in coal bed methane resources but still lacks in methane development techn... more ABSTRACT India is rich in coal bed methane resources but still lacks in methane development technologies. To begin understanding this prospective source, in the present investigation, microbial methane production was examined from bituminous, subbituminous and lignite coals obtained from Jharia coal mines in India. Microbial populations were enriched over a period of 21 days on various methanogenic specific substrates including the three ranks of coal. Maximum methane production (49%) was obtained on Methanosprillium sp specific medium (sodium acetate and isopropanol) supplemented with subbituminous coal at 65 °C and pH 6.8. Phylogenetic analysis of 16S rRNA gene sequences from the selected CBM65 consortium revealed a syntrophic association between a hydrogenotrophic methanogen Methanoculleus thermophiles and fermentative bacteria Comamonas sp. This is the first report of methane production by a consortium enriched from Indian coal bed methane reservoirs at such high temperature. The results of this study shed light on the fact that Jharia coal mines are methanogenically active and offer a prospective source for coal bed methane extraction. It is also, considered as the richest source of methane in India further this data will help in determining the potential role of methane emitted from this site in influencing the global carbon cycle.
To compare few phenotypic and genotypic characteristics of two desulfurizing bacterial strains, M... more To compare few phenotypic and genotypic characteristics of two desulfurizing bacterial strains, Mycobacterium phlei SM120-1 and Mycobacterium phlei GTIS10. In the present study, dibenzothiophene (DBT) desulfurizing activity, composition of fatty acids of cell membranes, DBT sulfone monoxygenase gene (bdsA) and the selection pressure applied during the growth and enrichment of the bacterial strains M. phlei SM120-1 and M. phlei GTIS10 were compared in our laboratory. The DBT desulfurization activity of M. phlei SM120-1 was found to be 0.17 +/- 0.02 micromol 2-HBP min(-1) (gram dry cell weight)(-1) and that of the bacterial strain M. phlei GTIS10 was 1.09 +/- 0.05 micromol 2-HBP min(-1) (gram dry cell weight)(-1). Fatty acid methyl ester analysis of cell membranes of these two bacterial strains in the presence of light gas oil showed that both the strains had different fatty acid profiles in their cell membranes. Comparison of the full gene sequences of the desulfurization gene bdsA in the two bacterial strains showed significant difference in the bdsA gene sequences. There was a significant difference observed in the selection pressure applied during the growth and enrichment of the two bacterial strains. The results of the comparative study of the bacterial strains, M. phlei SM120-1 and M. phlei GTIS10 showed that there were considerable differences in the phenotypic and genotypic characteristics of these two strains. The present study would broaden the understanding of biodesulfurization trait at intra-species level.
Sulfate-reducing bacteria (SRB) developed biocathodes efficient for reduction of acetic and butyr... more Sulfate-reducing bacteria (SRB) developed biocathodes efficient for reduction of acetic and butyric acids to alcohols and acetone via direct electron transfer reaching current densities of 160-210 A m(-2).
A newly discovered enteric bacterium Leclercia adecarboxylata PS4040, isolated from oily sludge c... more A newly discovered enteric bacterium Leclercia adecarboxylata PS4040, isolated from oily sludge contaminated soil sample was reported for degradation of polycyclic aromatic hydrocarbons (Appl Environ Microbiol 70:3163-3166, 2004a). This strain could degrade 61.5% of pyrene within 20 days when used as sole source of carbon and energy. The time course degradation experiment detected several intermediate products and the metabolites were identified by gas chromatography mass spectrometry analysis. Metabolite I was the detected on the 5th day and was identified as 1-hydroxypyrene and was detected till 10th day. Metabolite II which was detected on 10th day was identified as 1,2-phenanthrenedicarboxylic acid. Metabolite III and Metabolite IV were identified as 2-carboxy benzaldehyde and ortho-phthalic acid, respectively and were detected in the culture broth on 10th and 15th day. 1,2-benzene diol (catechol) was the fifth metabolite detected in the culture extracts on the 15th day and was subsequently reduced on day 20. Identification of Metabolite I as 1-hydroxypyrene was further investigated as this intermediate was not previously reported as a ring oxidation product for degradation of pyrene by bacterial strains. Purification by preparative high performance liquid chromatography and nuclear magnetic resonance spectroscopy, confirmed the identification of Metabolite I as 1-hydroxypyrene. L. adecarboxylata PS4040 could also use 1-hydroxypyrene as a sole source of carbon and energy. Thus a probable pathway for degradation of pyrene by enteric bacterium is proposed in this study, with 1-hydroxypyrene as initial ring oxidation product.
The diversity among a set of bacterial strains that have the capacity to degrade total petroleum ... more The diversity among a set of bacterial strains that have the capacity to degrade total petroleum hydrocarbons (TPH) in soil contaminated with oily sludge (hazardous hydrocarbon waste from oil refineries) was determined. TPH is composed of alkane, aromatics, nitrogen-, sulfur-, and oxygen-containing compound, and asphaltene fractions of crude oil. The 150 bacterial isolates which could degrade TPH were isolated from soil samples obtained from diverse geoclimatic regions of India. All the isolates were biochemically characterized and identified with a Biolog microbial identification system and by 16S rDNA sequencing. Pseudomonas citronellolis predominated among the 150 isolates obtained from six different geographically diverse samplings. Of the isolates, 29 strains of P. citronellolis were selected for evaluating their genetic diversity. This was performed by molecular typing with repetitive sequence (Rep)-based PCR with primer sets ERIC (enterobacterial repetitive intergenic consens...
Biofuels Bioethanol production from lignocellulosics: an overview Bioethanol: a status review on ... more Biofuels Bioethanol production from lignocellulosics: an overview Bioethanol: a status review on metabolic pathway modification of certain ethanologenic bacteria through genetic engineering Bioethanol production technologies: economics, environmental impact, and policy Bio-hydrogen: applications and future prospects Methanogenesis from agro-industrial residues: potential and prospects Biomass- gasifier-based power plants: potential, problems and research needs for decentralized rural electrification Industrial solid waste Coal bed methane Bioreactors for waste water treatment Ceramic membrane filters from waste fly ash and their applications Technological options for municipal solid waste management Technological trends and opportunities in cogeneration Environmental regulations in India for waste management
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