earticle

영어

This study will present efficient and environmental-friendly methods for the pretreatment of rice straw by using planetary or attrition mills. Both mill modes are effective to reduce size and cellulose crystallinity in rice straw. The relative crystallinity indexs were 0.20 and 0.69 for planetary milled and attrition milled samples. Enzymatic treatment of the milled rice straw produced both glucose and xylose. Total monosaccharides produced in enzymatic hydrolysis were 0.39 and 0.37 g/g rice straw for planetary and attrition mill treated, respectively. In comparison experiment to chemical pretreatments, none of the rice straw biomass was lost during the milling processes but it showed a 32.3 % and 10.3 % reduction in the SAA and NaOH pretreatments, respectively. Soaking the rice straw in both the aqueous ammonia and sodium hydroxide solutions led to the production of 0.95 and 2.34 g/l of freely soluble phenolic compounds, respectively. In contrast, the planetary and attrition mill pretreatments produced 3- to 9-fold less phenolics. To further investigate, the toxicity of each hydrolysate samples, a recombinant bacterium E. coli strain DH5α/pDMA3 was employed. The hydrolysates from the NaOH and SAA treatment elicited a 31-fold and 6-fold induction in bioluminescence while no induction was seen for both the planetary and attrition mills.