Unraveiling the characteristics of beneficial bacteria isolated from a polluted siie and their application in soil quality enhancement

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Emerging economies such as India face a greater challenge toward sustainable agriculture in today's world, Farmers have been encouraged to use chemical fertilizers and pesticides indiscriminately to grow more food in less area. As a result, the yield has increased, but environmental damages have negated these benefits. It also harmed soil fertility, which in turn harmed agricultural yield. Conversely, uncontrolled population growth, urbanization, and socioeconomic progress have boosted living standards. These generate massive amounts of municipal solid trash worldwide, particularly in India. It primarily pollutes soil and water with various pollutants such as heavy metals and other comparable things. Present thesis research aims to address this issue. Soil samples were collected from the Baragaon dumping site in Guwahati, Assam, contaminated with municipal solid waste (MSW) and has a common border with the ecologically sensitive Deepor Beel area (Ramsar site No. i207). According to the analysis, these soil samples had tire least soil nutrition and the high heavy metals level. With selective medi4 approximately 400 Phosphate solubilizing bacteria (PSB) and 350 N fixing bacteria (NFB) r,,'ere isaiated fiom soil samples. Following molecular characterization, the diversity of llscillus sp., Enterobacter sp., and Paraburkholderia.fungorum was discovered. Furthermore, the PSB were cultured in Pikovskaya (PVK) medi4 resulting in organic acid and enhanced acid phosphatase (ACP) activity. SM_ SS8 had the best Cd and Cu tolerance capacity among all the tested strains (up to 100 mg L-1). The growth pattern of SM_SS8 was investigated using optical density (OD) and kinetic growth measurements. Infrared spectroscopy (IR) and X-Ray Diffraction (XRD) studies were used to examine the strain's Cd and Cu degradation capability. The optimum concentration of Cd and Cu bio-precipitation*n in the SM_SS8 cell was studied using SEM-EDX. In Cd treated bacterial cell cultures, flow cytometry analysis revealed that- 70.92% , 46,93% and 20.4 % of viable SM_SS8 bacterial cells were identified in 10,50, and 100 mg L-1 respectively- A pot experiment also investigated the potential of biochar, bioferlilizer, and their formulation to remediate HMS-contaminated soils and improve soil quality and plant production (like tomato). The pot experiment results demonstrated that biofertilizer and biochar have a synergistic impact, resulting in improved soil nutrition and plant growth. Simultaneously, bacterial taxonomic analysis of harvested soil samples revealed that, the treated samples had higher diversity when compared to CK. The findings showed that a single biofertilizer and its formulation were best 1br various soil features such as physico-chemical, microbial diversity, and biochemical parameters.
Supervisor: Mitra, Sudip