Conversion of rice straw to sugars by microbial hydrolysis

Abstract

Rice straw is one of the most abundant lignocellulosic wastes in the world. It contains 47 % cellulose, 25 % hemicellulose and 5 % lignin. The cellulose and hemicellulose in rice straw can be converted into glucose and other fermentable sugars via microbial hydrolysis. These sugars can then be used as feedstocks for bioethanol production. The purpose of this work was to investigate the possibility of using rice straw as a raw material for microbial hydrolysis to produce sugars using bacteria isolated from Thai higher termites, Microceroterms sp. The effects of particle size (40 mesh, 60 mesh and 80 mesh), hydrolysis temperature (30 °C and 37 °C), amount of malt extract in 65 modified DSMZ broth medium 2 and bacteria strains (A 002 and M 015) were investigated. Qualitative and quantitative analysis of the sugars were determined by high performance liquid chromatography (HPLC) with a refractive index detector. The maximum sugar concentration of 0.97 g/L at 9 h and 37 °C was obtained with 80 mesh rice straw using strain A002 and 10 g/L malt extract in the production medium.