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Production of propyl gallate in nonaqueous medium using cell‐associated tannase of Bacillus massiliensis : Effect of various parameters and statistical optimization
Author(s) -
Aithal Mahesh,
Belur Prasanna D.
Publication year - 2013
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1068
Subject(s) - gallic acid , tannase , chemistry , biocatalysis , propyl gallate , gallate , propanol , chromatography , organic chemistry , nuclear chemistry , catalysis , reaction mechanism , methanol , antioxidant
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 μg/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.