Faculty Publications
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Publications by NITK Faculty
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Item Enhancement of a Novel Extracellular Uricase Production by Media Optimization and Partial Purification by Aqueous Three-Phase System(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2015) Ram, S.K.; Raval, K.; JagadeeshBabu, P.E.Uricase (urate: oxygen oxidoreductase, EC 1.7.3.3), an enzyme belonging to the class of oxidoreductases, catalyzes the enzymatic oxidation of uric acid to allantoin and finds a wide variety of application as therapeutic and clinical reagent. In this study, uricase production ability of the bacterial strains isolated from deep litter poultry soil is investigated. The strain with maximum extracellular uricase production capability was identified as Xanthomonas fuscans subsp. aurantifolii based on 16S rRNA sequencing. Effect of various carbon and nitrogen sources on uricase productivity was investigated. The uricase production for this strain was optimized using statistically based experimental designs and resulted in uricase activity of 306 U/L, which is 2 times higher than initial uricase activity. Two-step purification, such as ammonium sulfate precipitation and aqueous two-phase system, was carried out and a twofold increase in yield and specific activity was observed. © 2015 Taylor and 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 Process optimisation for improved chitinase production from marine isolate Bacillus haynesii and bioethanol production with Saccharomyces cerevisiae(Springer Nature, 2025) Govindaraj, V.; Anandan, D.K.; Kim, S.-K.; Raval, R.; Raval, K.In the quest for sustainable fuel sources, chitin-based biorefineries are gaining recognition as chitin is the second most abundant bioresource after cellulose. This approach not only provides an effective method for converting shell waste from seafood processing into valuable bioethanol but also helps in waste management. In this study, Bacillus haynesii, a marine isolate, was investigated and this is the first report on optimisation of process parameters for chitinase production from Bacillus haynesii. The One Factor at a Time (OFAT) method was used to optimize process parameters including inoculum age, inoculum size, temperature, pH, and filling volume, with colloidal chitin identified as the best carbon source for the growth of Bacillus haynesii. The Plackett-Burman Design (PBD) was employed to screen media components, followed by optimization using the Taguchi Orthogonal Array method. The media components investigated included glycerol, yeast extract, MnCl2·4H2O, MgSO4·7H2O, NH4Cl, and colloidal chitin. As a result, the optimized media—comprising 7.5 g/L yeast extract, 7.5% (w/v) glycerol, 0.6% (w/v) colloidal chitin, 1.44 g/L MnCl2·4H2O, and 1.2 g/L MgSO4·7H2O—yielded an enzyme activity of 6.85 U/mL with a specific activity of 28.87 U/mg. Furthermore, ethanol production from chitin oligosaccharides by Saccharomyces cerevisiae was quantified using the potassium dichromate oxidation method, achieving a bioethanol concentration of 2.48% v/v from 33.18 g/L of chitin oligosaccharides. These results demonstrate the potential of Bacillus haynesii-derived chitin oligosaccharides as a promising substrate for bioethanol production. © The Author(s) 2025.