Browsing by Author "Kumar, Madan"

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Genome sequence of carbon dioxide-sequestering serratia sp. strain ISTD04 isolated from marble mining rocks
(American Society for Microbiology, 2016) Kumar, Manish; Gazara, Rajesh Kumar; Verma, Sandhya; Kumar, Madan; Verma, Praveen K.; Thakur, Indu Shekhar
The Serratia sp. strain ISTD04 has been identified as a carbon dioxide (CO2)-sequestering bacterium isolated from marble mining rocks in the Umra area, Rajasthan, India. This strain grows chemolithotrophically on media that contain sodium bicarbonate (NaHCO3) as the sole carbon source. Here, we report the genome sequence of 5.07 Mb Serratia sp. ISTD04.
Genome sequence of pandoraea sp. ISTKB, a lignin-degrading betaproteobacterium, isolated from rhizospheric soil
(American Society for Microbiology, 2016) Kumar, Madan; Gazara, Rajesh Kumar; Verma, Sandhya; Kumar, Manish; Verma, Praveen K.; Thakur, Indu Shekhar
We report here the genome sequence of Pandoraea sp. ISTKB, a betaproteobacterium isolated from rhizospheric soil in the backwaters of Alappuzha, Kerala, India. The strain is alkalotolerant and grows on medium containing lignin as a sole carbon source. Genes and pathways related to lignin degradation were complemented by genomic analysis.
Genomic and proteomic analysis of lignin degrading and polyhydroxyalkanoate accumulating beta-proteobacterium Pandoraea sp ISTKB
(BioMed Central Ltd, 2018) Kumar, Madan; Verma, Sandhya; Gazara, Rajesh Kumar; Kumar, Manish; Pandey, Ashok; Verma, Praveen K.; Thakur, Indu Shekhar
Background: Lignin is a major component of plant biomass and is recalcitrant to degradation due to its complex and heterogeneous aromatic structure. The biomass-based research mainly focuses on polysaccharides component of biomass and lignin is discarded as waste with very limited usage. The sustainability and success of plant polysaccharide-based biorefinery can be possible if lignin is utilized in improved ways and with minimal waste generation. Discovering new microbial strains and understanding their enzyme system for lignin degradation are necessary for its conversion into fuel and chemicals. The Pandoraea sp. ISTKB was previously characterized for lignin degradation and successfully applied for pretreatment of sugarcane bagasse and polyhydroxyalkanoate (PHA) production. In this study, genomic analysis and proteomics on aromatic polymer kraft lignin and vanillic acid are performed to find the important enzymes for polymer utilization. Results: Genomic analysis of Pandoraea sp. ISTKB revealed the presence of strong lignin degradation machinery and identified various candidate genes responsible for lignin degradation and PHA production. We also applied label-free quantitative proteomic approach to identify the expression profile on monoaromatic compound vanillic acid (VA) and polyaromatic kraft lignin (KL). Genomic and proteomic analysis simultaneously discovered Dyp-type peroxidase, peroxidases, glycolate oxidase, aldehyde oxidase, GMC oxidoreductase, laccases, quinone oxidoreductase, dioxygenases, monooxygenases, glutathione-dependent etherases, dehydrogenases, reductases, and methyltransferases and various other recently reported enzyme systems such as superoxide dismutases or catalase-peroxidase for lignin degradation. A strong stress response and detoxification mechanism was discovered. The two important gene clusters for lignin degradation and three PHA polymerase spanning gene clusters were identified and all the clusters were functionally active on KL-VA Conclusions: The unusual aerobic'-CoA'-mediated degradation pathway of phenylacetate and benzoate (reported only in 16 and 4-5% of total seguenced bacterial genomes), peroxidase-accessory enzyme system, and fenton chemistry based are the major pathways observed for lignin degradation. Both ortho and meta ring cleavage pathways for aromatic compound degradation were observed in expression profile. Genomic and proteomic approaches providedvalidation to this strain's robust machinery for the metabolism of recalcitrant compounds and PHA production and provide an opportunity to target important enzymes for lignin valorization in future.
Production and characterization of polyhydroxyalkanoate from lignin derivatives by Pandoraea sp. ISTKB
(American Chemical Society, 2017) Kumar, Madan; Singhal, Anjali; Verma, Praveen Kumar; Thakur, Indu Shekhar
The present study investigates polyhydroxyalkanoate (PHA) production from lignin and its derivatives by a previously reported lignin-degrading bacterial strain Pandoraea sp. ISTKB. PHA production was screened by fluorescence microscopy and flow cytometry using a Nile red stain. PHA and biomass accumulation, while screening, was found to be maximum on 4-hydroxybenzoic acid followed by p-coumaric acid, vanillic acid, 2,6-dimethoxyphenol, and kraft lignin after 96 h. Monomer composition was analyzed by gas chromatography–mass spectrometry (GC–MS) and was followed by Fourier transform infrared and 1H NMR analysis, indicating PHA to be a copolymer of P(hydroxybutyrate-co-hydroxyvalerate). Genomic analysis of Pandoraea sp. ISTKB also complemented the results of GC–MS and NMR, and the relevant genes responsible for the synthesis of small chain length PHA were discovered in the genome. Process parameters were optimized by response surface methodology for enhanced production of PHA and biomass on 4-hydroxybenzoate. Optimization results showed 30 and 66% increase in the biomass and PHA production, respectively. The results obtained were promising and indicated that if lignin is depolymerized into low-molecular-weight intermediates, then it can easily be utilized and converted into value-added products like PHA by microbes.