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Browsing Theses by Supervisor "Chhabra, Meenu"
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Item Bioremediation of Low Level Uranium (VI) Waste Including Denitrification Using Microbial Fuel Cell(Indian Institute of Technology Jodhpur, 2019-01) Chhabra, MeenuNuclear wastes emerging from nuclear fuel cycle plants are generally rich in nitrates and heavy metals like Uranium. Nitrate and uranium have been identified as the major groundwater contaminants. Microbial fuel cells (MFCs) have the potential for denitrification and power production. However, the reported rates of denitrification in MFCs are low and there are no reports of U (VI) removal and/or simultaneous nitrate and U (VI) removal in a MFC. In this work, denitrification rate in a MFC is improved first by identifying an effective microbial consortium. High-rate denitrifying MFCs were developed using cow manure and soil. Further, the consortium was acclimatized under autotrophic (AD) and heterotrophic (HD) conditions to compare the power output and nitrate removal rate. The microbial communities were identified and found to exhibit resilience and high diversity. AD supported high power and HD supported high nitrate removal rate. Also, the abundance of denitrifying genes was assessed and they were present in both the conditions. The U (VI) was removed as a phosphate precipitate. Microbes at cathode produced phosphatase which liberated phosphate from an organic compound. Nitrate acted as an electron acceptor thereby allowing simultaneous nitrate and U (VI) removal. The work is extended to real low level effluents from nuclear fuel recycle division at BARC (Bhabha Atomic Research Centre), Mumbai. The MFC removed nitrate from these wastes while supporting power generation. In summary, this thesis work demonstrates the application of MFC for the removal of nitrate and U (VI) from contaminated water.Item Isolation, Identification, and Characterization of Oleaginous Yeast Capable of Growing and Producing Lipids on Agro- industrial Waste.(Indian Institute of Technology Jodhpur, 2020-01) Chhabra, MeenuBioenergy has the potential to provide future energy security. Biofuels are the energy sources derived from living organisms or the waste generated by them. Biodiesel is alkyl esters derivatives of long-chain fatty acids using bio-based oils. In this study, oleaginous yeast (Cystobasidium oligophagum) was isolated from soil rich in cellulosic waste. The yeast was isolated based on its ability to accumulate acellular lipid, grow on carboxymethylcellulose (CMC), and oduce lipase. It could accumulate up to 39.4445 ± 1.1995 % lipids in a glucose medium (12.4533 ± 00.9743 g/L cell dry weight). It was able to grow and accumulate lipids (36.4615 ± 1.4997 %) in the medium containing CMC as the sole substrate. It could also grow and produce lipids on several other industrial wastes such as glycerol, starch, xylose, and lactose. The lipid profile of the organism was suitable for obtaining biodiesel with desirable fuel properties. The isolate could grow on dairy cheese whey as a substrate. It was used either untreated (UCW) or deproteinized (DCW). Cheese whey supported suitable biomass and lipid productivities with a value of 0.0760 ± 0.0004 g/L. h (biomass) and .0335 ± .0004 g/L. h (lipid) on 100 % DCW. The soluble chemical oxygen demand (sCOD) removal rate was 8.0490 ± 0.1980 and 10.6103 ± 0.1656 g/L. d. The yeast could also grow on lignocellulosic hydrolysates. It also exhibited moderate resistance to furfural, 5-(hydroxymethyl) furfural, and acetic acid found in the lignocellulosic biomass hydrolysates. In summary, the thesis discusses promising oleaginous yeast for biodiesel production.