Faculty Publications
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Item Enhancement of propyl gallate yield in nonaqueous medium using novel cell-associated tannase of bacillus massiliensis(2013) Aithal, M.; Belur, P.D.Enzymatic synthesis of propyl gallate in organic solvent was studied using cell-associated tannase (EC 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as the biocatalyst. The effects of solvent, surfactant treatment, and bioimprinting on the propyl gallate synthesis were studied and subsequently optimized. Among various solvents, benzene followed by hexane was found to be the most favorable. Treatment of the biocatalyst with Triton X-100 at a lower concentration (0.2% w/v), before lyophilization, increased the propyl gallate yield by 24.5% compared to the untreated biocatalyst. The biocatalyst was imprinted with various concentrations of gallic acid and tannic acid. Biocatalyst imprinted with tannic acid showed 50% enhancement in the propyl gallate yield compared to the non-imprinted biocatalyst. © 2013 Taylor & Francis Group, LLC.Item Isolation and screening of endophytes from the rhizomes of some Zingiberaceae plants for L-asparaginase production(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Krishnapura, P.R.; Belur, P.D.Endophytes are described as microorganisms that colonize the internal tissues of healthy plants without causing any disease. Endophytes isolated from medicinal plants have been attracting considerable attention due to their high biodiversity and their predicted potential to produce a plethora of novel compounds. In this study, an attempt was made to isolate endophytes from rhizomes of five medicinal plants of Zingiberaceae family, and to screen the endophytes for L-asparaginase activity. In total, 50 endophytes (14 bacteria, 22 actinomycetes, and 14 fungi) were isolated from Alpinia galanga, Curcuma amada, Curcuma longa, Hedychium coronarium, and Zingiber officinale; of these, 31 endophytes evidenced positive for L-asparaginase production. All the L-asparaginase-positive isolates showed L-asparaginase activity in the range of 54.17–155.93 U/mL in unoptimized medium. An endophytic fungus isolated from Curcuma amada, identified as Talaromyces pinophilus, was used for further experiments involving studies on the effect of certain nutritional and nonnutritional factors on L-asparaginase production in submerged fermentation. Talaromyces pinophilus initially gave an enzyme activity of 108.95 U/mL, but gradually reduced to 80 U/mL due to strain degeneration. Perhaps this is the first report ever on the production of L-asparaginase from endophytes isolated from medicinal plants of Zingiberaceae family. © 2016, Taylor & Francis Group, LLC.Item Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity(Elsevier Ltd, 2017) Chandrasekar, C.; Belur, P.D.; Iyyaswami, R.Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents. © 2017 Elsevier LtdItem Enhancement of n-3 polyunsaturated fatty acid glycerides in Sardine oil by a bioimprinted cross-linked Candida rugosa lipase(Elsevier Inc. usjcs@elsevier.com, 2018) Sampath, C.; Belur, P.D.; Iyyaswami, R.Considering the advantages of bioimprinting and carrier free immobilization, cross-linked enzyme aggregates (CLEA) were prepared by using bioimprinted Candida rugosa lipase (CRL) with Bovine serum albumin (BSA), Polyethyleneimine and glutaraldehyde. Effect of various factors such as CRL-Oleic acid ratio, CRL-BSA ratio, CRL- Polyethyleneimine ratio, glutaraldehyde loading, cross-linking time etc., on lipase activity recovery and aggregate yield were studied and optimized. This immobilized lipase (CRL-CLEA) was used for the selective hydrolysis of ester linkages of non-PUFA glycerides, with an aim to concentrate EPA and DHA glycerides in the Sardine oil. Imprinting with oleic acid in the presence of ethanol and Tween 60, and further immobilization with co-aggregates and cross-linking agent showed 10.4 times higher degree of hydrolysis compared to free enzyme. As result, 2.83-fold increase of n-3 PUFA content in deacidified oil was obtained by using CRL-CLEA. The resultant oil had negligible di- and triglycerides content, proving higher efficiency in hydrolysing ester bonds of fatty acids, other than n-3 PUFA. Reusability studies showed CRL-CLEA could be reused up to 5 runs without a substantial reduction in its performance. Improvement in degree of hydrolysis, thermostability, efficiency of hydrolysis and reusability were achieved due to bioimprinting and subsequent immobilization of CRL in the form of CLEA. © 2017 Elsevier Inc.Item A novel fibrinolytic serine metalloprotease from the marine Serratia marcescens subsp. sakuensis: Purification and characterization(Elsevier B.V., 2018) Krishnamurthy, A.; Belur, P.D.This study demonstrates the purification and characterization of a fibrinolytic serine metalloprotease from the marine Serratia marcescens subsp. sakuensis (KU296189.1). The purified enzyme (1033 U/mg) had a molecular weight of 43 KDa, with optimum pH and temperature being 7 and 55 °C. The in vitro half-life of the fibrinolytic enzyme at 37 °C was found to be 19 h. The kinetic constants, Km and Vmax of the purified enzyme determined using fibrin as substrate was 0.66 mg/mL and 158.73 U/mL. The Kcat and catalytic efficiency of the enzyme was found to be 12.21 min?1 and 18.32 mL/(mg min) respectively. The fibrinolytic enzyme did not show any proteolytic activity towards blood plasma proteins like haemoglobin, ?-globulins and transferrin. In vitro studies revealed that the fibrinolytic enzyme displayed 38% clot lysis for a period of 3 h which was higher than that displayed by streptokinase and heparin. A total of seven peptide sequences were obtained after the LC-MS/MS-TOF analysis, out of which only four sequences showed 67% homology with the sequences of the other proteases. All these results suggest its novelty and potential application in thrombolytic therapy. © 2018 Elsevier B.V.Item Optimization of oxalate-free starch production from Taro flour by oxalate oxidase assisted process(Bellwether Publishing, Ltd., 2021) Kizhakedathil, M.P.; Suvarna, S.; Belur, P.D.; Wongsagonsup, R.; Agoo, E.M.G.; Janairo, J.I.B.Taro (Colocasia esculenta) starch is known to possess unique physical and functional properties such as low amylose content, A-crystalline form, small granules, higher swelling power, etc. Due to the presence of significant amount of calcium oxalate crystals, the food industry is reluctant to explore this unique and cheap starch source for various food applications. Traditional processes utilizing various physical and chemical methods to remove oxalate content of starch inevitably change its physical and functional properties. However, using oxalate oxidase can effectively remove oxalates without altering the unique properties of starch. Hence, an attempt was made to optimize oxalate oxidase assisted starch extraction process from taro flour using response surface methodology. A central composite design comprising 20 experimental trials with 10 cube points augmented with six axial points and four replicates at the center point was applied. A mathematical model was developed to show the effect of taro flour concentration, enzyme load and incubation time on the oxalate removal. Validity of the model was experimentally verified and found that 98.3% of total oxalates can be removed under optimal conditions. This is the first report of optimization of the production of starch from taro flour using microbial oxalate oxidase. © 2020 Taylor & Francis Group, LLC.Item Production of tannase from a newly isolated yeast, Geotrichum cucujoidarum using agro-residues(Taylor and Francis Ltd., 2024) Thangavelu, N.; Jeyabalan, J.; Veluchamy, A.; Belur, P.D.With an aim of producing commercially important tannase enzyme using cheap and readily available agro-residues, leaves of Indian Gooseberry (Phyllanthus emblica) and Jamun (Syzygium cumini), peels of Lemon (Citrus limon), and Pomegranate (Punica granatum) were screened. Newly isolated Geotrichum cucujoidarum was utilized for the study. Preliminary studies indicated that tannase titer obtained is not proportional to the tannin content of the agro-residues and solid state fermentation superior compared to submerged fermentation. Jamun mixed with lemon peel in equal proportion supplemented with minerals under solid-state fermentation gave a tannase titer of 15.46 U/g dry solids. Through successful implantation of Plackett–Burman design, yeast extract concentration, inoculum volume, and amount of substrate were found to be the most significant factors. Further optimization of these three factors through Response Surface Methodology resulted in the 1.7-fold increase in tannase titer. Validation experiments using 3.97 g of Jamun leaves + lemon peel powder mixed with a nutrient solution having (w/v) yeast extract − 1.1%, dextrose − 3%, Urea − 1.125%, potassium chloride − 0.1%, magnesium sulfate heptahydrate − 0.1% with the initial pH of 5, inoculated with 2.48 ml of inoculum gave a tannase titer of 26.43 U/g dry solids after 6 days of solid-state fermentation. © 2023 Taylor & Francis Group, LLC.Item Simultaneous partitioning of multiple bioactive compounds from Garcinia indica rinds in a three-liquid-phase extraction systems(Taylor and Francis Ltd., 2025) Shanbhag, C.C.; Salimuddin, R.M.H.; Iyyaswami, R.; Belur, P.D.Simultaneous extraction and purification of principal bioactive compounds, anthocyanins (ACNs), garcinol (GL), and hydroxycitric acid (HCA) from the rinds of Garcinia indica (Kokum) fruits in a single-step using Three Liquid Phase Systems (TLPS) were investigated. Among the various phase-forming components studied, TLPS formed by n-hexane-ethanol-(NH4)2SO4-water system was considered for partitioning GL into the n-hexane-rich top phase, ACNs into the ethanol-rich middle phase, and HCA into the aqueous salt-rich bottom phase. The present system was even able to separate carbohydrates into the bottom phase, which can be detrimental to the stability of ACNs. The effect of n-hexane, ethanol, and (NH4)2SO4 concentration on the partitioning behavior of biomolecules was analyzed. The TLPS composed of water-n-hexane-ethanol-(NH4)2SO4 could purify and extract 95.08% of ACNs, 95.33% of GL, and 67.98% of HCA in a single-step extraction process while the other extraction methods require multi-step extraction process to separate these three compounds. The effect of pH studies on the partitioning characteristics of biomolecules revealed that pH 4 is optimum and more efficient than the native pH of the system to achieve maximum yield of all the bioactive compounds. © 2025 Taylor & Francis Group, LLC.