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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 Optimization of culture medium for novel cell-associated tannase production from bacillus massiliensis using response surface methodology(2012) Belur, P.D.; Goud, R.; Goudar, D.C.Naturally immobilized tannase (tannin acyl hydrolase, E.C. 3.1.1.20) has many advantages, as it avoids the expensive and laborious operation of isolation, purification, and immobilization, plus it is highly stable in adverse pH and temperature. However, in the case of cell-associated enzymes, since the enzyme is associated with the biomass, separation of the pure biomass is necessary. However, tannic acid, a known inducer of tannase, forms insoluble complexes with media proteins, making it difficult to separate pure biomass. Therefore, this study optimizes the production of cell-associated tannase using a "protein-tannin complex" free media. An exploratory study was first conducted in shake-flasks to select the inducer, carbon source, and nitrogen sources. As a result it was found that gallic acid induces tannase synthesis, a tryptose broth gives higher biomass, and lactose supplementation is beneficial. The medium was then optimized using response surface methodology based on the full factorial central composite design in a 3 l bioreactor. A 2 3 factorial design augmented by 7 axial points (? = 1.682) and 2 replicates at the center point was implemented in 17 experiments. A mathematical model was also developed to show the effect of each medium component and their interactions on the production of cell-associated tannase. The validity of the proposed model was verified, and the optimized medium was shown to produce maximum cell-associated tannase activity of 9.65 U/l, which is 93.8% higher than the activity in the basal medium, after 12 h at pH 5.0, 30°C. The optimum medium consists of 38 g/l lactose, 50 g/l tryptose, and 2.8 g/l gallic acid. © The Korean Society for Microbiology and Biotexhnology.