Enhancement of tannase production by Lactobacillus plantarum CIR1: validation in gas-lift bioreactor

The optimization of tannase production by Lactobacillus plantarum CIR1 was carried out following the Taguchi methodology. The orthogonal array employed was L18 (2¹ × 3⁵) considering six important factors (pH and temperature, also phosphate, nitrogen, magnesium, and carbon sources) for tannase biosynthesis. The experimental results obtained from 18 trials were processed using the software Statistical version 7.1 using the character higher the better. Optimal culture conditions were pH, 6; temperature, 40 °C; tannic acid, 15.0 g/L; KH₂PO₄, 1.5 g/L; NH₄Cl, 7.0 g/L; and MgSO₄, 1.5 g/L which were obtained and further validated resulting in an enhance tannase yield of 2.52-fold compared with unoptimized conditions. Tannase production was further carried out in a 1-L gas-lift bioreactor where two nitrogen flows (0.5 and 1.0 vvm) were used to provide anaerobic conditions. Taguchi methodology allowed obtaining the optimal culture conditions for the production of tannase by L. plantarum CIR1. At the gas-lift bioreactor the tannase productivity yields increase 5.17 and 8.08-fold for the flow rates of 0.5 and 1.0 vvm, respectively. Lactobacillus plantarum CIR1 has the capability to produce tannase at laboratory-scale. This is the first report for bacterial tannase production using a gas-lift bioreactor.