Browsing by Author "Pranjali Vishwakarma"

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Bio-filtration of trichloroethylene using diazotrophic bacterial community
(Elsevier Ltd, 2010) Awadhesh K. Shukla; Pranjali Vishwakarma; R.S. Singh; S.N. Upadhyay; Suresh K. Dubey
Biodegradation of TCE was studied in a biofilter packed with wood charcoal and inoculated with diazotrophic bacterial community isolated from local soil. Steady state TCE removal efficiencies higher than 85% were observed up to inlet load of 2.866 g m-3 h-1. The maximum elimination capacity of 5.31 gm-3 h-1 was observed at an inlet load of more than 7.90 g m-3 h-1. The biofilter was sensitive to fluctuations in the process conditions but could easily recover its performance after 10 days shutdown. Almost constant and small pressure drop per unit length and very negligible compaction was observed during the whole experimental period. The molecular analyses such as RT-PCR and gene sequencing revealed the presence of functionally active Azospirillum species in the biofilm. © 2009 Elsevier Ltd. All rights reserved.
Biodegradation of trichloroethylene (TCE) by methanotrophic community
(2009) Awadhesh K. Shukla; Pranjali Vishwakarma; S.N. Upadhyay; Anil K Tripathi; H.C. Prasana; Suresh K. Dubey
Laboratory incubation experiments were carried out to assess the potential of methanotrophic culture for degrading TCE. Measurements of the growth rate and TCE degradation showed that the methanotrophs not only grew in presence of TCE but also degraded TCE. The rate of TCE degradation was found to be 0.19 ppm h-1. The reverse transcriptase-PCR test was conducted to quantify expression of pmoA and mmoX genes. RT-PCR revealed expression of pmoA gene only. This observation provides evidence that the pmoA gene was functionally active for pMMO enzyme during the study. The diversity of the methanotrophs involved in TCE degradation was assessed by PCR amplification, cloning, restriction fragment length polymorphism and phylogenetic analysis of pmoA genes. Results suggested the occurrence of nine different phylotypes belonging to Type II methanotrophs in the enriched cultures. Out of the nine, five clustered with, genera Methylocystis and rest got clustered in to a separate group. © 2008 Elsevier Ltd. All rights reserved.
Diversity of endophytic bacterial community inhabiting in tropical aerobic rice under aerobic and flooded condition
(Springer, 2020) Pranjali Vishwakarma; Suresh Kumar Dubey
The role and activity of bacterial endophytes remains largely unexplored and detail insight into Indian rice agro ecosystem is still little explored. In this study, we examined the diversity of endophytic bacteria in aerobic rice (variety ARB6) under aerobic and flooded field conditions. Based on 16S rRNA gene RFLP cloning sequencing, 900 clones with 144 representatives (72 aerobic and 72 flooded) revealed majority of clones affiliated to Gammaproteobacteria (64.58%), Betaproteobacteria (9.72%), Alphaproteobacteria (17.36), Firmicutes (6.26%) and Bacteroidetes (2.08). The study suggests that the aerobic rice variety harbours plant growth promoting (PGP) genera (viz. Pantoea, Enterobacter, Paenibacillus, etc). Investigations on aerobic rice under aerobic and flooded conditions revealed high richness and diversity of endophytic bacteria under aerobic condition inferring that the endophytic bacteria are beneficial for rice growth and productivity, and hence, would be helpful in designing better strategies for rice cultivation under drought or water scarce conditions. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Diversity of methanotrophs in urea-fertilized tropical rice agroecosystem
(2010) Pranjali Vishwakarma; Suresh K. Dubey
Laboratory experiments were conducted to study the population size, diversity and methane oxidation potential of methanotrophs in tropical rice agroecosystem under the influence of N-fertilizer. Results indicate that the diversity of methane oxidizing bacteria (MOB) is altered in fertilizer treated soils compared to untreated control. Nevertheless, Type I MOB still dominated in the fertilized soils whereas the diversity of Type II methanotrophs decreases. Control soils have higher MOB population and CH4 oxidation capacity than fertilized soils. Rhizospheric soil is more populated than non-rhizospheric soil in both unfertilized and fertilized conditions. Variation in Km and Vmax of methane oxidation in soils appears to be due to variation in methanotrophic community. Experimental results indicate that methanotrophic community differs both quantitatively and qualitatively in unfertilized and fertilized soils. © 2010 Association of Microbiologists of India.
DNA microarray analysis targeting pmoA gene reveals diverse community of methanotrophs in the rhizosphere of tropical rice soils
(2010) Pranjali Vishwakarma; Suresh K. Dubey
The diversity of the methanotrophs community of two different rice fields of a typical tropical rice agroecosystem was assessed using microarray targeting pmoA gene-based approach. The presence of types I and II methanotrophs was observed with the dominance of Methylocystis in both the fields. The study revealed that the Barkachcha rice field harbours more diverse groups of methanotrophs than the Ghazipur rice field. It was also observed that in some members of types I and II methanotrophs, even the peat-associated group was present in the enriched culture of the soils. The Ghazipur soil and its enriched mixed methanotrophic culture showed higher methane oxidation potential than the Barkachcha soil. These results suggest that the methanotrophs community and its potential for methane oxidation vary with change in soil type within the same ecosystem.
Ecological and molecular analyses of the rhizospheric methanotroph community in tropical rice soil: Effect of crop phenology and land-use history
(2009) Pranjali Vishwakarma; M.G. Dumont; L. Bodrossy; N. Stralis-Pavese; J.C. Murrell; Suresh K. Dubey
To study the effect of crop phenology and cultivation practices on methanotrophic communities, two tropical rice fields located in the upper Gangetic plain of India with similar soil type and different cropping history were selected. A laboratory incubation experiment for the enumeration of methanotrophs and for the measurement of CH4 oxidation potential was conducted on a parallel basis. The methanotroph population size was found to be significantly higher in the Banaras Hindu University (BHU), Varanasi soil than the Indian Institute of Vegetable Research (IIVR), Varanasi soil. The population size increased with the age of the plant for both the sites. The CH4 oxidation potential was higher with the BHU soil compared to the IIVR soil. The CH4 oxidation rate increased significantly from tillering to flowering to grain-filling stages, and finally there was no significant difference between the grain-filling and the grain-maturation stages. A diagnostic microarray targeting the pmoA gene and a 16S rRNA denaturing gradient gel electrophoresis (DGGE)-based approach were applied to assess the diversity of the methanotrophic community for the two sites. A broad diversity of methanotrophs was detected at both sites, including type I and type II methanotrophs of the genera Methylobacter, Methylomonas, Methylosarcina, Methylosphaera, Methylomicrobium and Methylocystis. Type II methanotrophs were found in higher abundance as compared to type I methanotrophs at both the sites. DGGE analysis indicated that the methanotroph community in BHU soil was more or less stable, while little variation was found in IIVR soil during crop growth.
The effect of soil type and plant age on the population size of rhizospheric methanotrophs and their activities in tropical rice soils
(2007) Pranjali Vishwakarma; Suresh Kumar Dubey
A laboratory incubation experiment was conducted in tropical rain-fed (red soil) and irrigated (black soil) rice agroecosystem during the crop growing season to determine the effect of the type of soil, cultivation practices and the age of plant on MOB (methane oxidizing bacteria) population size and their activities. The average value of MOB population size was 11.7 ± 4.5 × 105 cells gasoil, with a range of 3.1 ± 0.4 to 21.2 ± 1.0 × 105 cells g-1 soil for red soil, which was lower in comparison to black soil where population size varied between 84.2 ± 3.8 and 289.4 ± 7.0 ± 105 cells g -1 soil with an average of 182.8 ± 53.5 × 105 cells g-1 soil. The highest population size was recorded during the grain maturation stage which gradually declined during the grain filling, flowering and tillering stages of the rice plants. The HSD test indicated a significant variation in the MOB population size with the varying ages of the plant. CH4 oxidizing capacity was higher in black soil as compared to red soil. The highest CH4 oxidizing capacity was found at the grain-filling stage in both the soil types. The differences in soil types and cultivation practices, pattern of variation in MOB population size and methane oxidation were found similar in both the sites under the influence of plant age, even though the detected values differed significantly. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.