(348d) KINETICS of ACID Hydrolysis of Sagarcane Bagasse

Agro-residue lignocellulosic biomass is available abundantly and can be used as a potential feedstock for bioethanol production. We have studied production of bioethanol from sugarcane bagasse. Several thermophilic strains were isolated from the soil samples collected from a bagasse storage site. A microorganism that showed fermentation activity on most substrates was selected for fermentation of sugars hydrolyzed from bagasse to ethanol. The microorganism was characterized as yeast Kluyveromyces sp. IIPE453. The yeast strain showed growth and fermentation on glucose, mannose, galactose, xylose, sucrose, cellobiose and lactose. The optimum temperature and pH for growth and fermentation were found to be 50 ºC and 5.0, respectively.

Before the fermentation, the bagasse biomass was hydrolyzed to monomer sugars by sulfuric acid. Bagasse yielded various sugars like glucose, galactose, xylose, arabinose, cellobiose etc. when hydrolyzed with sulfuric acid. By two-stage hydrolysis, first with dilute acid and then with concentrated acid, about 92 % of the sugars present in bagasse could be recovered keeping the formation of toxic compounds like furfural relatively low. In this paper, we have presented the results of hydrolysis study. The concentrations of various sugars and furfural as functions of reaction time, acid concentration, and temperature are given. We observed that the acid hydrolysis of bagasse could be modeled as first-order two-step consecutive reactions, where the polysaccharides first break into monomers through hydrolysis and then break into degradation products. The experimental data could be well correlated by this model.