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Abstract:
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Marine Aspergillus awamori BTMFW032, recently reported by us, produce
acidophilic tannase as extracellular enzyme. Here, we report the application of this
enzyme for synthesis of propyl gallate by direct transesterification of tannic acid and in
tea cream solubilisation besides the simultaneous production of gallic acid along with
tannase under submerged fermentation by this fungus. This acidophilic tannase enabled
synthesis of propyl gallate by direct transesterification of tannic acid using propanol as
organic reaction media under low water conditions. The identity of the product was
confirmed with thin layer chromatography and Fourier transform infrared spectroscopy.
It was noted that 699 U/ml of enzyme could give 60% solubilisation of tea cream within
1 h. Enzyme production medium was optimized adopting Box–Behnken design for
simultaneous synthesis of tannase and gallic acid. Process variables including tannic acid,
sodium chloride, ferrous sulphate, dipotassium hydrogen phosphate, incubation period
and agitation were recognized as the critical factors that influenced tannase and gallic acid
production. The model obtained predicted 4,824.61 U/ml of tannase and 136.206 μg/ml gallic
acid after 48 h of incubation, whereas optimized medium supported 5,085 U/ml tannase and
372.6 μg/ml of gallic acid production after 36 and 84 h of incubation, respectively, with a
15-fold increase in both enzyme and gallic acid production. Results indicated scope for
utilization of this acidophilic tannase for transesterification of tannic acid into propyl gallate, tea
cream solubilisation and simultaneous production of gallic acid along with tannase |