Statistical optimization of simultaneous saccharification and l(+)-lactic acid fermentation from cassava bagasse using mixed culture of lactobacilli by response surface methodology

Optimization of five process parameters (concentrations of cassava bagasse, enzyme, yeast extract, NH4Cl and inoculum) was attempted using a Box-Behnken design for the optimal production of l(+)-lactic acid by a mixed culture of Lactobacillus casei and Lactobacillus delbrueckii by simultaneous saccharification and fermentation. Maximum lactic acid yield of 81 g/L was obtained when 15% (w/v) cassava bagasse treated with 12.5 mL/L enzyme mixture was supplemented with 7.5 g/L yeast extract and 3 g/L NH4Cl and inoculated with 3 × 1010 CFU/L of lactobacilli and incubated for 60 h at 37 °C as static culture.