Response Surface Methodology as an Approach for Optimization of Vinegar Fermentation Conditions Using Three Different Thermotolerant Acetic Acid Bacteria

Abstract

This study aimed to investigate optimal fermentation conditions of biological acetic acid fermentation for vinegar production. Optimization was performed on 3 acetic acid bacteria strains namely VMA1, VMA7 and VMAO using Response Surface Methodology (RSM). A Box-Behnken-Design (BBD) was achieved with three different independent process parameters involving: fermentation temperature, original alcohol concentration and original acetic acid concentration and one dependent variable (acetic acid yield). The results showed that the mathematical models describe correctly the relationship between responses and factors ( F values of the models (p < 0.05), R 2 (coefficient of correlation) respectively 0.96, 0.94, 0.98, and adjusted R 2 0.95, 0.92, 0.98). The maximum acidity was obtained respectively at fermentation temperatures, original alcohol concentrations and original acetic acid concentrations ranging from [37.5 °C - 45 °C ], [16 % - 20% (v/v)], [1.5 % - 2% (w/v)] for VMA1, [40 °C - 45 °C ], [14.5 % - 20% (v/v)], [1.7 % - 2% (w/v)] for VMA7 and [42 °C - 45 °C ], [17 % - 20% (v/v)], [1.5 % - 2% (w/v)] for VMAO. The use of these acetic strains in the production of vinegar may seriously lead to a decrease or even an ablation of the costs related to the cooling of bioreactors especially in warm and hot countries, in the context of global warming.