MICROBIAL PRODUCTION OF TANNASE USING AGRO-INDUSTRIAL WASTES

Abstract

In this work, microbial sources can be used in the biotechnological synthesis of tannase. Microbial tannases are preferred because they are more stable and produced in higher yields than similar ones acquired from other sources. In addition, they can be exposed to genetic manipulation more easily than plants and animals. Tannase has a wide range of industrial uses, including food, and environmental biotechnology. A total, 255 isolates (16, 78, and 161 isolates of yeast, bacteria, and fungi), respectively were obtained from different sources of food, soil, and seawater). Only 10 fungal isolates among 255 gave the highest tannase index on solid medium supplemented with tannic acid as a sole carbon source. Two fungal isolates of T11 and SWP33 were selected which appeared a high significant tannase (122.2 and 127.6 U/ml), gallic acid production (255.4 and 238.4 mg/ml) and the tannin degradation percentage reached to 89.8 and 88.7%, respectively. Both isolates were identified based on morphological, cultural characters, and further confirmation by sequencing the 18S rRNA gene and was identified as Aspergillus niger ok 626231 (SWP33) and Penicillium griseoroseum ok 626651 (T11). Maximum tannase (147.0 and 148.7 U/ml) and GAC (255 and 258 mg/ml) production by A. niger SWP33 and P. griseoroseum T11 in the presence of tannic acid was attained on the fourth and fifth days of fermentation, with specific enzyme and GA rates of 0.0332 and 0.0274 h-1 and 0.0089 and 0.0099 h-1, respectively. The tested strains were cultivated on tannins-rich wastes as a low-cost medium for tannase production using submerged and solid-state cultures techniques. Results indicated that the solid-state fermentation was more preferred for tannase (~40 and ~25 % over increase) and gallic acid (~39