Bioethanol production from Lantana camara (red sage): Pretreatment, saccharification and fermentation

Lantana camara contains 61.1% (w/w) holocellulose and can serve as a low-cost feedstock for bioethanol production. Acid hydrolysis (3.0%, v/v H2SO4, 120 °C for 45 min) of L. camara produced 187.14 mg/g total sugars along with fermentation inhibitors such as phenolics (8.2 mg/g), furfurals (5.1 mg/g) and hydroxy methyl furfurals (6.7 mg/g). Sequential application of overliming (pH 10.0) and activated charcoal (1.5%, w/v) adsorption was used to remove these toxic compounds from the acid hydrolysate. The acid-pretreated biomass of L. camara was further delignified through combined pretreatment of sodium sulphite (5.0% w/v) and sodium chlorite (3.0% w/v), which resulted in about 87.2% lignin removal. The enzymatic hydrolysis of delignified cellulosic substrate showed 80.0% saccharification after 28 h incubation at 50 °C and pH 5.0. Fermentation of acid and enzymatic hydrolysates with Pichia stipitis and Saccharomyces cerevisiae gave rise to 5.16 and 17.7 g/L of ethanol with corresponding yields of 0.32 and 0.48 g/g after 24 and 16 h, respectively.