Science & Technology
Permanent URI for this community
Browse
Browsing Science & Technology by TU Affiliated Institute "Central Campus of Technology, Hattisar, Dharan,"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item Mass Production of Free-Living and Symbiotic Nitrogen-Fixing Biofertilizers and Comparative Efficacy Study of Different Carriers(Deparment of Microbiology, 2022) Karki, SujanThere is a high demand for food worldwide which has caused the increase in the use of chemical fertilizer to fulfill the global need for food. The use of chemical fertilizer has a negative impact on the environment which has exponentially raised the global interest in microbial fertilizer. This study focuses on the easy and costeffective use of carrier material that can be used in the production of microbial fertilizer. For these symbiotic bacteria (Rhizobium) and non-symbiotic bacteria (Azotobacter) were used as microorganisms and charcoal, rice husk, and farmyard manure as carrier material were used. Rhizobium species and Azotobacter species were isolated from pea plant root nodule and soil sample respectively. These isolated organisms were blended with carrier material and kept in two different temperatures i.e. at room temperature and refrigerator to know the survivability of microorganisms in normal conditions and preserved condition. A decline in moisture and pH on prolonged incubation was observed in both organisms. A high survivable rate of Rhizobium species is seen in rice husk and Azotobacter species is seen in farmyard manure stored in both temperatures. Whereas least survivability was seen in charcoal for both organisms stored in both temperature. Moisture and pH are normally responsible for more 50% of change in CFU in all carrier material except for rice husk blended with Rhizobium and farm yard manure blended with Azotobacter stored in room temperature. CFU in all the carrier material with respect to storage and carrier material have significant difference except for Azotobacter stored in room temperature. The rhizobia and Azotobacter strains population significantly decline over time regardless of the carrier material and storage temperature. A decline in population on prolonged incubation may be attributed to the depletion of nutrients, moisture, and cell death. Rice husk, however, demonstrated extraordinary potential, particularly in respect of shelf life. KEYWORDS: Rhizobium, Azotobacter, carrier, biofertilizerItem Nitrogen Fixation Evaluation of Azotobacter Chroococcum Isolated from Soil of Forest(Deparment of Microbiology, 2022) Tolangi, PriskilaWith the continuous use of chemical fertilizers in Agriculture system may help to produce sufficient amount of food for growing population but these chemicals have an adverse effect both on the environment and living organisms. Biofertilizers are a promising alternative to hazardous chemical fertilizers and gaining importance for attaining sustainable agriculture. They play key role in maintaining soil health and plants. Microorganisms can interact with the crop plants and enhance their immunity, growth, and development. Nitrogen, Phosphorous, Potassium are the essential nutrients required for the growth of crops, but these nutrients are naturally present in insolubilized forms. Certain microorganisms make them soluble and can be easily assimilated by plants for their growth and development. In this study, Azotobacter chroococcum were isolated from forest surroundings of Panbari Dharan. 25 soil samples were collected in sterile bag and cultured in Ashby’s media by serial dilution and incubated at 30˚C for 5 days. Morphological, cultural, biochemical characterization was done and bacteria were identified. Isolated A. chroococcum was cultured in Ashby’s broth and inoculated on tomato seedlings by root dipping technique. It was found that tomato plants inoculated with A. chroococcum has significant growth in height, no. of leaves and root length than that of untreated tomato plants. The research result showed that this strain had positive effect on the increase of nitrogen content of soil. On the base of this study, it is concluded that Azotobacter chroococcum has positive effect in growth of plants. It could be good biofertilizer as an alternative to nitrogen fertilizer. Keywords: soil, free-living nitrogen fixers, nitrogen, PGPR effects, tomato plantsItem Optimization of Humectants During Preparation of buffalo Jerky type product and its storage stability(Department of Food Technology, 2022) Basnet, AnilThe present study optimized the concentration of different humectants in pretreatment infusion by response surface methodology. The concentration of salt, sucrose, brown sugar, maltodextrin and citric acid used were 0 to 9 g, 0 to 9 g, 0 to 3 g, 0 to 3 g, and 0 to 3 g respectively. The best-optimized sample obtained through DE® and sensory analysis was compared with the control sample (without pretreatments of humectants) concerning storage stability for 30 days in 5 days intervals at 5% level significance. From graphical and numerical optimization, the optimized combination obtained was 4 g salt, 2 g sucrose, 2 g brown sugar, 1.5 g maltodextrin, and 0.5 g citric acid giving buffalo jerky with moisture content, water activity, fat content, crude protein, ash content, pH of 10.96%, 0.63 at 20.5 ⁰ C, 4.51%, 85.47%, 8.4% and 5.62 respectively. The sensory and microbial quality of the buffalo jerky prepared from pretreated humectants mixture meat was found significantly superior to untreated (control) samples, with comparable proximate compositions. Salt concentration was more effective in reducing the water activity of the jerky than other humectants used in the present study. Crude protein content and pH were not significantly different (P>0.05) between the optimized sample and control sample whereas moisture content, fat, ash content, and water activity were significantly different (P<0.05). There was a significant difference (P<0.05) between the optimized and control samples in terms of storage stability. The optimized jerky sample was stable for 30 days at room temperature without any decrease in sensory quality and microbiological spoilage to the control jerky sample which lasted for only 20 days at room temperature.Item Phytochemical Screening of Ethnomedicinal Herbal Extracts and Their Effect on Microbial Quality of Sukuti(Department of Food Technology, 2022) Rai, Sangen RumaThe main objective of the study was to screen phytochemical constituents of ethnomedicinal herbs and to determine their effect on the microbial quality of sukuti. Specific objectives include preparation of herbal extracts, isolation, and identification of microorganisms from sukuti, determination of antimicrobial property of herbal extracts, and microbial analysis of herbal sukuti. Four ethnomedicinal herbs (Zanthoxylum armatum, Litsea cubeba, Heracleum nepalense, and Evodia fraxinifolia) having culinary importance were selected for the study. For the preparation of herbal extract, herbs were ground (particle size < 250 µ), treated with 50% ethanol (v/v), and concentrated in a rotary vacuum evaporator at 50 v o C. Four of the spoilage and pathogenic microorganism viz. Salmonella, Staphylococcus, E. coli, and Lactic acid bacteria were isolated and identified from the sukuti samples for the study. Herbal extracts at the concentration of 40, 20, 10, and 2 mg/ml were tested against the isolates to determine the antimicrobial property of the extracts. The best herb with optimum concentration was selected based on its antimicrobial activity. Zanthoxylum armatum at 40 mg/ml concentration showed the highest zone of inhibition against the test organisms and therefore selected for final product development. Meat strips (1 cm 1 cm 25 cm) were marinated with Zanthoxylum armatum (40 mg/ml) extract at the rate of 2%, aged (24 h at 4 ± 2C), and dried at cabinet drier for 2 days at 55C. Total Plate Counts of control (untreated) and herbal sukuti (treated) were carried out for 20 days within an interval of 10 days to determine the microbial stability of the final product. The total plate count for treated sample was significantly lower (p<0.05) than that of untreated sample.