Faculty Publications

Now showing 1 - 4 of 4

Production of propyl gallate in nonaqueous medium using cell-associated tannase of Bacillus massiliensis: Effect of various parameters and statistical optimization
(2013) Aithal, M.; Belur, P.D.
Enzymatic synthesis of propyl gallate in an organic solvent was studied using cell-associated tannase (E.C. 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as a biocatalyst. The influence of buffer pH and strength, water activity, temperature, biocatalyst loading, gallic acid concentration, and 1-propanol concentration was studied by the one-factor-at-a-time method. Subsequently, response surface methodology was applied based on a central composite design to determine the effects of three independent variables (biocatalyst loading, gallic acid concentration, and 1-propanol concentration) and their mutual interactions. A total of 20 experiments were conducted, and a statistical model was developed, which predicted the maximum propyl gallate yield of 20.28 ?g/mL in the reaction mixture comprising 40.4 mg biocatalyst, 0.4 mM gallic acid, and 6.52 % (v/v) 1-propanol in 9.5 mL benzene at 30°C. The subsequent verification experiments established the validity of the model. Under optimal conditions, 25% conversion of gallic acid to propyl gallate was achieved on a molar basis. The absence of the need for enzyme purification and subsequent immobilization steps and good conversion efficiency makes this enzyme system an interesting one. Reports on the applications of bacterial whole cell systems for synthetic reactions in organic solvents are scarce, and perhaps this is the first report on bacterial cell-associated tannase-mediated esterification in a nonaqueous medium. © 2013 International Union of Biochemistry and Molecular Biology, Inc.
Enhancing gallic acid content in green tea extract by using novel cell-associated tannase of Bacillus massiliensis
(2013) Palabhanvi, B.; Belur, P.D.
Gallic acid content in green tea extract was enhanced by using a novel cell-associated tannase of Bacillus massiliensis. Biomass that contains tannase was used for this study. The activity of the cell-associated tannase was stable during 1 week of storage in the refrigerator. Response surface methodology was applied based on central composite design to determine the effects of three independent variables (pH, temperature and incubation time) and their mutual interactions. A total of 16 experiments were conducted; and a statistical model was developed, which predicted 475.74mg/L gallic acid production at pH6.2, 36C and incubation period of 16.71h. The subsequent verification experiments confirmed the validity of the model. Under optimal conditions, 84.7% of the total hydrolyzable tannins were converted to gallic acid and glucose. This naturally immobilized tannase was stable enough to be used for up to 12 runs. Practical Applications: The current study shows that naturally immobilized tannase of Bacillus massiliensis can be used instead of artificially immobilized tannase. Such naturally immobilized tannase has many advantages as it avoids expensive and laborious isolation, purification and immobilization. Ease of separation of cell-associated enzyme from the reaction mixture and absence of any detectable extracellular tannase activity after enzymatic treatment are some of the encouraging facts. Stability during storage up to 7 days, 85% tannic acid hydrolyzing efficiency, activity at pH3.5-8.0 and operational stability for 12 runs are some of the interesting features of this naturally immobilized enzyme. However, its application for tea treatment will be limited until Bacillus massiliensis gets "Generally Recognized As Safe" status. It can be employed, however, for production of gallic acid from agro residues and production of propyl gallate. © 2012 Wiley Periodicals, Inc.
Purification of Glutaminase from Zygosaccharomyces rouxii in Polyethylene Glycol– Sodium Sulphate Aqueous Two-Phase System
(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2015) Bolar, S.; Iyyaswami, R.; Belur, P.D.
L-glutaminase (EC 3.5.1.2) produced from Zygosaccharomyces rouxii NRRL-Y 2547 was partitioned in an aqueous two phase system comprising PEG 2000 and sodium sulphate. The effects of tie line length (TLL), pH, broth loading (BL), volume ratio, and neutral salt concentration on enzyme partitioning and purification were investigated. The optimal condition for the partitioning of glutaminase was obtained through response surface methodology and obtained the partition coefficient and yield of 12.99 and 95.12%, respectively. The purification factor of 5.59 and selectivity of 6.52 were achieved at the optimal condition. © © Taylor & Francis Group, LLC.
Partitioning of bio-active compounds from rinds of garcinia indica using aqueous two-phase system: Process evaluation and optimization
(Elsevier B.V., 2020) Nainegali, B.S.; Iyyaswami, R.; Belur, P.D.
The simultaneous extraction of anthocyanins (ACNs), garcinol (GL), isogarcinol (IGL) and hydroxycitric acid (HCA) from the rinds of Garcinia indica (GI) fruit and their partition behaviour in the aqueous two-phase system (ATPS) formed by 1-propanol-(NH4)2SO4 was investigated. The effect of different variables that govern the partition characteristics were studied and the amount of crude loaded into the ATPS, the concentration of 1-propanol and (NH4)2SO4 were found to be the significant variables. The Response Surface Methodology (RSM) was adopted to optimize the process variables through desirability based multi-response optimization for the partitioning of GL and IGL to the alcohol rich top phase and ACNs and HCA to the salt-rich bottom phase by considering the partitioning coefficients (K) and extraction efficiency of all the four bioactive components as responses. A ATPS consisting of 15.202% (w/w) 1-propanol, 10.242% (w/w) (NH4)2SO4 having the TLL of 28.505% (w/w) at a crude load of 25% (w/w) able to partition 97.39% GL (K = 370.770) and 92.38% IGL (K = 120.581) in the top phase and 99.19% ACNs (K = 0.080) and 99.83% HCA (K = 0.016) in the bottom phase with a purity higher than 99% by implementing secondary ATPS. © 2020 Elsevier B.V.

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