Simultaneous detoxification, saccharification and co-fermentation of oil palm empty fruit bunch hydrolysate for l-lactic acid production by Bacillus coagulans JI12

Abstract

Bacillus coagulans JI12 was used to produce l-lactic acid from both cellulose and hemicellulose sugars of oil palm empty fruit bunch hydrolysate at 50°C without sterilization prior to fermentation. In fermentation of mixed glucose and xylose (10g/L:100g/L or 50g/L:53g/L), both sugars were simultaneously converted to l-lactic acid. B. coagulans JI12 was tolerant against up to 4g/L of furfural and 20g/L of acetate and able to metabolize furfural to 2-furoic acid. After acid hydrolysis, both the hemicellulosic and cellulosic fractions of oil palm empty fruit bunch were fermented to lactic acid in a simultaneous detoxification, saccharification and co-fermentation process supplemented with 25 FPU Cellic® CTec2 cellulase per g cellulose, yielding 80.6g/L of lactic acid with a productivity of 3.4g/L/h. Neither pre-detoxification nor separation of fermentable sugars from lignin was required. These results indicate that B. coagulans JI12 is a promising strain for l-lactic acid production from lignocellulosic biomass. © 2013 Elsevier B.V.