Rakshit, AmitavaGarg, Jancy2019-11-052019-11-052019Plasticshttp://krishikosh.egranth.ac.in/handle/1/5810134363Plastics are ubiquitous in modern life. Recently, its abundance due to increased use has affected most of the agricultural lands of the world. A small intervention was taken to collect soil from the plastic dumping site of Varanasi. Thereafter, microbes were isolated and cultured for studying the microbial degradation of plastic. Simultaneously, a pot experiment was also conducted in the net house of the Department of Soil Science & Agricultural Chemistry, Institute of Agricultural Sciences, BHU, Varanasi with three different soils, viz., red soil, black soil, and alluvial soil of the Indo-Gangetic Plains. The soils were treated with seven types of plastics varying in colour. Different soil properties, viz., pH, EC, available, N, P, and K, and organic carbon were analysed. The use of plastics in the soils mostly affected the nitrogen chemistry in soil rather than the other soil analysed properties. Biochemical characterization and morphology study of the microbes from the dumping site and agricultural soils were also assessed for categorizing them as plastic degrading microbes (PDM). Twenty isolates were cultured from the dumping site; out of which three isolates (PDM-5, PDM-9, and PDM-12) were found to be different in characteristics.After gram staining PDM-5 was showing purple color and rods in chain hence gram +ve and bacillus; PDM-9 was pink colored and coccus in chains were seen hence gram –ve and coccus; PDM-12 was showing purple color and rods in chains hence gram -ve and bacillus. In catalase test, PDM-5 was showing +ve response, PDM-12 was showing –ve, whereas PDM-9 was also showing +ve response. In oxidase test, PDM-5 and and PDM-9 were showing +ve response but PDM-12 was showing –ve response. The result of mannitol test was +ve for all the three isolates. Response towards methyl test was found to be +ve in case of PDM-5 and PDM-9 only. It was evident from our study that dumping sites mostly contain the population of bacillus and coccus bacteria as plastic degrading microorganisms whereas in case of the agricultural soils of Varanasi, the dominance of bacillus was noted.Further, it can be inferred that microbial biodegradation of plastic material is a complex phenomenon. Nature line experiments are difficult to realize in laboratory due to the greater number of parameters occurred during biogeochemical processes which can’t be reported and controlled in vitro. For exploiting high diversity of microbes it has to be experimented under diverse conditions.ennullThesis