Production of lactic acid from carob, banana and sugarcane lignocellulose biomass

Lignocellulosic biomass from agricultural residues is a promising feedstock for lactic acid (LA) production. The aim of the current study was to investigate the production of LA from different lignocellulosic biomass. The LA production from banana peduncles using strain Bacillus coagulans with yeast extract resulted in 26.6 g LA·L⁻¹, and yield of 0.90 g LA·g⁻¹ sugars. The sugarcane fermentation with yeast extract resulted in 46.5 g LA·L⁻¹, and yield of 0.88 g LA·g⁻¹ sugars. Carob showed that addition of yeast extract resulted in higher productivity of 3.2 g LA·L⁻¹·h⁻¹ compared to without yeast extract where1.95 g LA·L⁻¹·h⁻¹ was obtained. Interestingly, similar LA production was obtained by the end where 54.8 and 51.4 g·L⁻¹ were obtained with and without yeast extract, respectively. A pilot scale of 35 L using carob biomass fermentation without yeast extract resulted in yield of 0.84 g LA·g⁻¹ sugars, and productivity of 2.30 g LA·L⁻¹·h⁻¹ which indicate a very promising process for future industrial production of LA.