Journal Articles
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Item Production of novel cell-associated tannase from newly isolated Serratia ficaria DTC(2010) Belur, P.D.; Gopal, M.; Nirmala, K.R.; Nainegali, N.Five strains of tannic acid degrading bacteria were isolated and identified by phenotypic characterization. All the five isolates showed cell-associated activity, whereas only three showed extracellular activity. Serratia ficaria DTC, showing the highest cell-associated activity (0.29 U/l), was selected for further shake-flask studies. Tannase synthesis was growth associated and reached the peak in the late stationary phase of growth. Organic nitrogen sources enhanced the tannase production. Peak tannase production of 0.56 U/l was recorded in the medium having the initial pH of 6. The pH and temperature optima of the enzyme were found to be 8.9 and 35°C, respectively. This is the first report of cell-associated activity in the case of bacterial tannase. Cell-associated tannase of Serratia ficaria DTC could be industrially important from the perspective of its activity at broad temperature and pH ranges, and its unusually high activity at pH 8.9. © The Korean Society for Microbiology and Biotechnology.Item Microbial production of tannase: State of the art(2011) Belur, P.D.; Mugeraya, G.Tannin acyl hydrolase (E.C.3.1.1.20) is commonly referred as tannase, hydrolyses ester and depside bonds of hydrolysable tannins to produce gallic acid, glucose and galloyl esters. Tannase finds application in many industrial sectors which includes pharmaceutical, food, chemical and beverages industry. The enzyme has potential uses in the treatment of tannery effluents and pre-treatment of tannin containing animal feed. Since, the discovery of tannase in 1867, a great deal of research did happen on production aspects of tannase. Most of the research was focused on fungal tannase, as tannin was earlier considered as bacteriostatic. After the discovery of bacterial tannase in 1983, several studies on bacterial tannase were published. Despite the long history and numerous publications, tannase is still considered as one of the costly industrial enzymes. This is due to less titer and long fermentation time of the processes. In view of the growing demand, it is imperative to isolate high productive strains and develop economically feasible processes. This study reviews the microbial sources, isolation and screening methods, modes of production, substrates and media, temperature and pH of fermentation, duration of fermentation and location of tannase enzyme. An attempt is also made to give an outline of historical development which has taken place in tannase research.© 2011 Academic Journals Inc.Item Evaluation of feeding strategies for enhanced cell-associated tannase production by serratia ficaria dtc(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Belur, P.D.; Goudar, D.C.Batch studies on Cell-associated tannase production showed 2.6 U/L activity in the declining phase of growth in the bioreactor. It was observed that Cell-associated tannase production under declining phase was depending upon the bacterial biomass produced under exponential phase and gallic acid level. The peak production of enzyme was always accompanied by a sharp rise in dissolved oxygen concentration. Based on these observations, fed batch fermentation by feeding a mixture of nutrients (glucose and tryptose) and Dissolved oxygen (DO) based feeding strategy of gallic acid were designed. Nutrient feeding strategy showed 10 U/L of enzyme activity at 14th h of fermentation. DO based feeding strategy of gallic acid resulted in the production of 14.4 U/L enzyme activity in the 12th h of fermentation. The enzyme production rate of 1.2 U/L.h achieved in this mode was 4.6–fold greater than the values observed in batch process and 1.68 fold greater than the productivity achieved by feeding nutrients. Hence, DO based feeding strategy of gallic acid was proved to be an effective strategy for enhanced cell-associated tannase production by Serratia ficaria DTC. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Production of naringinase by a new soil isolate of Serratia Sp.: Effect of different carbon and nitrogen sources(2012) Pavithra, M.; Belur, P.D.; Saidutta, M.B.Four strains of Naringin degrading bacteria were isolated and tested for naringinase activity. All the four isolates showed extracellular naringinase activity. The one which showed consistently good activity in three different media was selected (2 U/L) and identified by phenotypic characterization as Serratia Sp. In shake-flask trials, effect of various carbon and nitrogen sources was studied. Among all the carbon sources, glucose enhanced the naringinase production. Peptone supplemented with ammonium nitrate was found to be favourable. Maximum of 9.2 U/L naringinase activity was achieved in the medium comprising naringin, glucose, peptone, ammonium nitrate and salts.Item 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.