Investigations on the Kinetics of Acid Catalyzed Hemicellulose Hydrolysis Derived from Waste Rice Straw for the Production of Bio-ethanol

Abstract

Objectives: To understand the monophasic kinetic behavior of hemicellulose hydrolysis and determination of thermodynamic parameters involved in dilute acid pretreatment by tartaric acid. Methods/Statistical Analysis: Biomass samples from thatched roofs were collected and analyzed for cellulose, hemicellulose and lignin through Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF) and Acid Detergent Lignin (ADL) methods. The ground biomass was hydrolysed with tartaric acid, saccharified applying cellulase, xylanase at different time/agitation speed for obtaining reducing sugar and finally fermented for ethanol yield. The kinetics of hemicellulose hydrolysis was critically studied in the present work. Findings: The maximum yield of xylose and reducing sugars after hydrolysis and saccharification at optimum conditions were 134 mg/g and 494.8 mg/g using tartaric acid as hydrolyzing media. Pichia stipitis was very effective for conversion of pentoses and hexoses during fermentation. The maximum ethanol yield of 25.1% using tartaric acid was obtained after fermentation. Overall, the present works depicts the introduction of a new hydrolytic agent, tartaric acid and a comprehensive view of the complete bio processing of waste rice straw to bioethanol. The amount of ethanol yield was from 17% to 25.1%. It was noticed that the ethanol content was directly proportional with the increase in age of the samples. An increasing trend of ethanol with time was visible until 9th hour. High ethanol yield was obtained in this study since Pichia stipitisstrain could utilize both hexose sugars and pentose sugars together. Applications/Improvements: Thatched rice straw roof can be better utilized for ethanol making with natural degradation of lignin due to aging instead of increasing environment pollution using significantly less synthetic enzymes.