Process parameters influencing tannase production by Aspergillus niger using mangrove (Rhizophora apiculata) bark in solid substrate fermentation

Abstract

Rhizophora apiculata bark is a tannin-rich waste material obtained from charcoal industry. This industrial waste was used as solid substrate in the study for the production of tannase and at the same time, help in minimizing the country’s industrial wastes. This study was carried out to optimize the physical parameters for the maximal tannase production by Aspergillus niger via solid substrate fermentation using a shake flask system. The optimized physical parameters obtained were combination of 0.75 and 2.00 mm of substrate particles at the ratio of 1: 1, Czapek- Dox medium as moisturizing agent at pH 7, initial moisture content of 1: 1.5 (w/v), incubation temperature at 30°C, mixing at every 24 h and the size of inoculum at 1 × 10⁶ spores/ml which finally, produced a maximum tannase of 4.97 U/g of fermented substrate on the 6^th day of cultivation.

Key words: Solid substrate fermentation, tannase, Aspergillus niger, Rhizophora apiculata barks.