Optimization of L-lactic acid production from banana peel by multiple parallel fermentation with Bacillus licheniformis and Aspergillus awamori

This study investigated the optimization of L-lactic acid production from banana peel as an unutilized biomass, by multiple parallel fermentation (MPF) with Bacillus licheniformis and Aspergillus awamori. To optimize L-lactic acid production, the factors studied consisted of banana peel, potassium dihydrogen phosphate, Tween 80, magnesium sulfate heptahydrate, sodium chloride, yeast extract, and ammonium sulfate. Optimization of these component factors was performed using the Taguchi method with an L8 orthogonal array. The optimal concentration for MPF using biomass substrate was as follows: L-lactic acid production was 28.01 g/L in the medium containing 10% banana peel, 0.5% potassium dihydrogen phosphate, 0.05% Tween 80, 0.1% magnesium sulfate heptahydrate, 0.1% sodium chloride, 1.5% yeast extract, and 0.2% ammonium sulfate. The result indicates that MPF with B. licheniformis and A. awamori could constitute part of a potential industrial application for banana peel as a currently unutilized biomass for L-lactic acid production.