http://202.45.146.37:8080/jspui/handle/123456789/5 Department of Microbiology 2026-10-09T08:51:21Z http://202.45.146.37:8080/jspui/handle/123456789/454 Title: EXAMINATION OF LEAD AND CADMIUM CONTAMINATION IN MARKET- SOURCED FILOPALUDINA BENGALENSIS FROM JHAPA, MORANG AND SUNSARI DISTRICTS, EASTERN NEPAL. Authors: KAFLE, SMARIKA Abstract: Heavy metal pollution from contaminated water sources threatens aquatic life and human health. In eastern Nepal where Freshwater Snails (Filopaludina bengalensis) are commonly consumed as an edible mollusc, these pollutants may be absorbed into the snails through polluted waters which could cause harm to those who consume them and to assess the level of lead (Pb) and cadmium (Cd) present in snails sold at various markets in Jhapa, Morang and Sunsari districts in eastern Nepal, Atomic Absorption Spectrophotometry (AAS) was used to measure the levels of these metals and statistical analysis was carried out to compare the levels of each metal within each of the sampled locations and also to find the association between Pb and Cd. A comparison of the average amount of Pb and Cd measured indicated that Pb was significantly greater than Cd at all the sampling locations. At Site 3, the highest overall concentration of heavy metals was observed while Site 5 demonstrated the lowest concentrations of heavy metals of both Pb and Cd. One-way Anova and Kruskal Wallis Tests revealed significant variation in Pb and Cd levels among sample sites (p<0.05). Analysis of paired comparisons confirmed that Pb levels were always greater than Cd levels at each site. However although there was a moderate positive association between Pb and Cd levels over sites this association was not statistically significant. These observations provide evidence for regional variations in the degree of contamination by heavy metals in Filopaludina bengalensis obtained from markets in eastern Nepal, also with lead being more problematic than cadmium in terms of contamination. Therefore, the results represent important baseline data on the levels of heavy metal contamination in commercially harvested freshwater snails and highlight the need for continued monitoring of freshwater foods for public health protection and improved food safety management in Nepal Description: FOR THE AWARD OF BACHELOR OF SCIENCE (Bsc.) IN BIOLOGY 2026-10-07T00:00:00Z http://202.45.146.37:8080/jspui/handle/123456789/414 Title: CHARACTERIZATION AND APPLICATION OF AMYLASE AND XYLANASE ENZYMES FROM BACILLUS CEREUS IN ENHANCING MANGO JUICE CLARIFICATION Authors: Thakur, Priyanka Abstract: Enzymes with potential industrial applications, including the food industry, include amylase and xylanase. Fruit juice contains a variety of sugars that must be clarified without compromising the juice's quality; therefore, appropriate, high-quality enzymes are crucial for this process. The purpose of this study was to separate and characterize bacteria that produce xylanase and amylase from soil and fruit peel samples that were gathered in the Kathmandu Valley. The amylase was produced in a conical flask with nutritional broth containing 1% starch at 37 °C in a rotatory water shaker bath at 120 rpm. After 24 hours, the mixture was centrifuged at 10,000 for 5 minutes. The amylase activity in the supernatant was measured using the DNSA technique. After isolating 17 amylase-producing bacteria, one (6%) of them produced xylanase and was recognized as Bacillus cereus by means of extensive characterization techniques such as colony morphology, staining, biochemical testing, and 16S rRNA sequencing. The ideal pH and temperature for B. cereus amylase production were found to be 7.0 and 40°C, respectively. Mango juice was successfully clarified using B. cereus-extracted enzymes, indicating their possible use in industrial operations. Additionally, analyses of the isolated enzymes' physicochemical characteristics and structure predictions were carried out. The B. cereus strain K21 has shown promise as a source of amylase and xylanase enzymes, and it is very adept at clarifying fruit juice. These results demonstrate the enzymes' industrial potential, especially in the food processing industry. Description: A Dissertation Submitted to the Department of Microbiology, Central Campus of Technology, Tribhuvan University, Dharan, Nepal, in Partial Fulfillment of the Requirements for the Award of Degree of Master of Science in Microbiology (Food) 2025-08-19T00:00:00Z http://202.45.146.37:8080/jspui/handle/123456789/305 Title: EXTRACTION OF ANTIBIOTICS BY ACTINOMYCETES ISOLATED FROM EASTERN MOUNTAIN REGION OF NEPAL Authors: Dhakal, Pradip Pratap Abstract: Bioactive compounds like antibiotic can be considered as a substance, produced by one microorganism, which inhibits the growth of another microorganism. Actinomycetes, slow growing gram-positive bacteria, are the major sources of bioactive compounds. The aim of this study was to screen antibiotic producing Actinomycetes for antibiosis from the soils of Eastern Mountain region of Nepal. Primary screening and secondary screening were performed by perpendicular streak method and agar well assay method respectively. Microbiological characterization was performed for identification of presumptive genera. Characterization of the antibacterial substances extracted from this isolate was done by Thin-layer chromatography (TLC) using Chloroform: Methanol (10:90) as the solvent system and iodine vapor as the visualizing agent. Altogether forty-one actinomycetes were isolated from soil samples but only one (2.4%) of the isolate showed antibacterial activity against both Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli, Salmonella Typhi Shigella spp., and Pseudomonas aeruginosa) test-bacteria in primary screening. Isolate M3 was selected for secondary screening because of its potent antibacterial activity. Minimum inhibitory concentration (MIC) of crude antibacterial substances was carried out by serial dilution method and found to be 2.5 mg/mL against test organisms. The chromatogram in TLC showed only one spot with Rf value 0.81 by the isolate suggesting that the isolate produced only one compound which was completely different from the spot with Rf value 0.89 produced by gentamycin. According to identification by Microscopy (1000X) and overall biochemical, and physiological characteristics, the isolate was considered as Streptomyces spp, a distinct taxonomic group. , Description: A Dissertation Submitted to the Department of Microbiology, Central Campus of Technology, Tribhuvan University, Dharan, Nepal, in Partial Fulfillment of the Requirements for the Award of Degree of Masters of Science in Microbiology (Public Health 2024-02-16T00:00:00Z http://202.45.146.37:8080/jspui/handle/123456789/293 Title: SUITABILITY ANALYSIS OF DRINKING WATER FROM THE SPRINGS OF DEUMAI WATERSHED ILAM, NEPAL Authors: SHRESTHA, PRIYA DARSHAN Abstract: Spring is one of the major sources of drinking water in hilly and Himalayan region. The aim of this study was to check whether the water was suitable for drinking or not by studying the physicochemical properties. Springs of Deumai watershed Ilam, Nepal was investigated for water samples and the physicochemical parameters studied were TDS, pH, temperature, total hardness, alkalinity, total iron and major ion concentrations (Na+ , K+ , Mg2+ , Ca2+, Cl– , SO4 2– , NO3 – ) to describe the water’s chemical characteristics. The determination of concentration of chemical parameters was performed by using spectrophotometric method, flame photometric method and titration method. According to the findings and comparison with the guidelines of drinking water given by World Health Organization (WHO) and National Drinking Water Quality Standard (NDWQS), the water quality for drinking water was found within the standards set by them. The average pH was found 7.47. And the dominance trend for major cations was Ca2+ > Na+ > Mg2+ > K+ and for anions was Cl– > NO3 – > SO4 2– . All the values obtain were within the range specified by WHO and NDWQS guidelines of drinking water. Description: A PROJECT WORK SUBMITTED TO THE DEPARTMENT OF CHEMISTRY CENTRAL CAMPUS OF TECHNOLOGY INSTITUTE OF SCIENCE AND TECHNOLOGY TRIBHUVAN UNIVERSITY NEPAL FOR THE AWARD OF BACHELOR OF SCIENCE (B.Sc.) IN CHEMISTRY 2023-07-23T00:00:00Z