Production of Bioethanol from Enzymatic and Dilute Acid Hydrolysate of Lantana camara in Batch Fermentation

Abstract

The presence of 62.2 % of total carbohydrates in Lantana camara makes it a potential and low-cost renewable material for bioethanol production. The wood dust slurry at 10 % (w/v) solid content when treated with 3 % (w/v) NaOH at room temperature for 4 hours resulted in 90.13 % delignification with phenolics yield of 268±15.79 mg/g of dry weight of substrate. Acid hydrolysis (2 % w/v sulfuric acid, 24 h) of delignified L.camara wood dust produced 181.86 mg/g total sugars along with fermentation inhibitors furfural and HMF (134±3.4 mg/l). The hydrolysate obtained after dilute acid hydrolysis was subsequently detoxified sequentially by the different detoxification methods such as ethyl acetate differential extraction, overliming, vaccum evaporation and activated charcoal to diminish the inhibition effect of different inhibitors. The cellulase enzyme prepared from Trichoderma viride was used to study the saccharification of the cellulose fiber from Lantana camara wood dust. The optimal saccharification yield (0.899 g of sugar/g of cellulose) was achieved after 12 h of incubation at optimal performance parameters when almost 82 % of cellulose depolymerization was obtained, resulting in sugar concentration of 45.75 g/l in hydrolysis medium. Fermentation of enzymatic and acid hydrolysates with Saccharomyces cerevisiae VS1 and Saccharomyces cerevisiae VS3 respectively gave rise to 43.56 g/L and 26.38 g/L of ethanol with corresponding yields of 0.44g/g and 0.26g/g after 24 and 48 h, respectively.