Building Block Lactic Acid from Rice Husks and Agave Bagasse

The biorefinery concept seeks openings to explore the wide availability of biomass left-over as feedstocks. The bioconversion of the hydrolysates of rice husks and agave bagasse in lactic acid using Lactobacillus rhamnosus was investigated. Pressurized hydrolysis led to the highest yields by 175 A degrees C (58.8 bar), for 46 min, using 0.8 % HCl or 2.2 % H2SO4 (v v(-1)). It was produced 106.6 mg glucose g(-1) rice husks and 90.9 mg glucose g(-1) agave bagasse for the HCl-hydrolysis, and 84.5 mg glucose g(-1) rice husks and 71.3 mg glucose g(-1) agave bagasse for the H2SO4-hydrolysis. To the rice husks, the fermentation produced up to 105.1 mg lactic acid g(-1) after 52 h HCl-fermentation, and 87.1 mg lactic acid g(-1), after 24 h H2SO4-fermentation. In the case of agave bagasse, the fermentation produced up to 90.1 mg lactic acid g(-1) (HCl-fermentation), and 67.9 mg lactic acid g(-1) (H2SO4-fermentation), after approx. 20 h. The hydrolysis of both biomass left-over showed a satisfactory production of glucose, which let to bypass the subsequent concentration stage prior fermentation. This study took advantage of multivariate approach, and its findings can be useful to design future bioconversion processes.