Optimisation of Lactic Acid Fermentation from Cassava Peel by Lactobacillus casei (ATCC334)

Abstract

The demand for lactic acid is steadily increasing due to the desire of its bioproduction over chemical synthesis. The associated cost, however, is a significant hurdle. This study reports lactic acid fermentation by Lactobacillus casei ATCC334 from cassava peel. It investigates the effect of unhydrolysed cassava peels, acidic, alkali hydrolysates; fermenting pH; substrate concentration; nitrogen source concentration; duration; and inoculum size. An attempt at a cheaper purification and recovery protocol relative to those currently in use was similarly performed. Acidic hydrolysate yielded 10.53%, unhydrolysed substrate gave 4.80% with alkali hydrolysate yielding 4.75%. The highest LA yield was obtained at pH 6.0, 2.0% v/v inoculum size, 25% w/v substrate concentration, 5% nitrogen source concentration. A post-optimisation combination yielded 18.3% LA suggesting that one-factor-at-a-time may be unsuitable for optimisation studies involving cassava peel and L. casei ATCC334. FTIR spectra of product suggests effective partial purification. Hence, an improvement in the optimization strategy for production is recommended for subsequent study.