Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
4 results
Search Results
Item Coconut coir pith, available in abundance especially in tropical countries, was studied as a substrate for the production of cellulase[1,4(1,3;1,4)???D?glucan 4?glucanohydrolase, EC 3.2.1.4] and ??D?glucosidase(??D?glucoside glucohydrolase, EC 3.2.1.21) in solid state fermentation. The effects of fermentation time, nutrient level, substrate particle size and inoculum size have been examined for optimal production of these enzymes by the fungal strain Aspergillus niger NCIM 1005. The highest filter paper activity (FPA) of 4.11 IU g?1, carboxyl methyl cellulose (CMCase) activity of 15·55 IU g?1 and cellobiase activity of 9·31 IU g?1 were obtained after 7 to 8 days of fermentation. Reese and Mandel's mineral solution in the substrate to mineral solution ratio of 1:10 (w/v) supported high cellulase and cellobiase activities. An inoculum size of 20–50% (v/v) based on the volume of mineral medium and substrate average particle size of 375 ?m were optimum for enzyme production. Copyright © 1994 SCI(Production of cellulases from coconut coir pith in solid state fermentation) Muniswaran, P.K.A.; Selvakumar, P.; Charyulu, N.C.L.N.1994Item Production of naringinase from a new soil isolate, Bacillus methylotrophicus: Isolation, optimization and scale-up studies(2014) Mukund, P.; Belur, P.D.; Saidutta, M.B.Five strains of naringin-degrading bacteria were isolated and found to be positive for extracellular naringinase activity. The one that showed highest activity in the selective medium was identified by 16S rRNA analysis as Bacillus methylotrophicus. The best combination of carbon-nitrogen source was determined by employing two-level full factorial analyses, comprising 24 experiments in shake flasks. Sucrose-yeast extract showed significant increase in naringinase activity (7.46 U/L) compared to the basal medium. Naringinase production was found to be inducible and naringin was found to be the best inducer among naringin, naringenin, hesperidin, and L-rhamnose. Inoculum size of 2% (v/v) and age of 48 hr favored naringinase and biomass production. Highest naringinase activity of 8 U/L was observed at the initial medium pH of 6. Response surface modeling was applied based on central composite design to determine the effects of three independent variables (sucrose, yeast extract, and naringin) and their mutual interactions. In total, 20 experiments were conducted and a statistical model was developed, which predicted naringinase production of 10.61 U/L. Subsequently, verification experiments were conducted and validity of the model was verified. Bioreactor studies conducted with the optimized medium showed an enzyme production of 12.05 U/L within 34 hr of fermentation. Copyright © Taylor & Francis Group, LLC.Item Scale-up of naringinase production process based on the constant oxygen transfer rate for a novel strain of Bacillus methylotrophicus(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2017) Raval, K.; Gehlot, K.; Belur, B.D.Naringinase bioprocess based on Bacillus methylotrophicus was successfully scaled up based on constant oxygen transfer rate (OTR) as the scale-up criterion from 5-L bioreactor to 20-L bioreactor. OTR was measured in 5 and 20-L bioreactor under various operating conditions using dynamic method. The operating conditions, where complete dispersion was observed were identified. The highest OTR of 0.035 and 0.04 mMol/L/s was observed in 5 and 20-L bioreactor, respectively. Critical dissolved oxygen concentration of novel isolated strain B. methylotrophicus was found to be 20% of oxygen saturation in optimized medium. The B. methylotrophicus cells grown on sucrose had maximum oxygen uptake rate of 0.14 mMol/L/s in optimized growth medium. The cells produced the maximum naringinase activity of 751 and 778 U/L at 34 hr in 5 and 20-L bioreactors, respectively. The maximum specific growth rate of about 0.178/hr was observed at both the scales of operations. The maximum naringinase yield of 160 and 164 U/g biomass was observed in 5 and 20-L bioreactors, respectively. The growth and production profiles at both scales were similar indicating successful scale-up strategy for B. methylotrophicus culture. © 2017 Taylor & Francis.Item Role of coconut shell biochar and earthworm (Eudrilus euginea) in bioremediation and palak spinach (Spinacia oleracea L.) growth in cadmium-contaminated soil(Academic Press, 2022) Noronha, F.R.; Manikandan, S.K.; Nair, N.The contamination of soil with heavy metals is known to affect the yield the soil fertility, which in turn affects the growth of agricultural crops. This study investigates the role of coconut shell biochar (CSB) and earthworms (Eudrilus euginea) in the bioremediation and growth of Palak spinach (Spinacia oleracea L.) in cadmium (Cd) contaminated soil. The soils were amended with different combinations of CSB and earthworms and incubated for 35 days. Later, the soil samples were analyzed for the changes in the soil properties, soil enzyme activity, and heavy metal contents. It is observed that the treatments with both CSB and earthworms resulted in the improvement of soil properties and soil enzyme activity which was directly related to soil fertility. Meanwhile, the maximum removal of 94.38% of total Cd content in the soil was obtained for the soil sample contain both CSB and earthworms. The improved soil properties resulted in a higher germination percentage of Spinacia oleracea L. seeds in the Cd contaminated soil. © 2021 Elsevier Ltd