Production of Reducing Sugar from Coffee Pulp Waste Using Mixture of Microorganisms, Enzymes, and Surfactants

Abstract

This study has successfully investigated the effect of microorganisms, enzymes, and surfactants mixture to produce a reducing sugar from Coffee pulp waste. The experiment consisted of microbial pretreatment to reduce lignin content followed by comparing the hydrolysis by enzymes and microorganism using a surfactant and without surfactant to get a higher yield of reducing sugar. Pretreatment was conducted by mixture of Bacillus subtilis (BS) with Trichoderma reesei (TR) in the ratio of 2:1 (v/v) and Aspergillus niger (AN) with TR in the ratio of 1:1 (v/v). BS-TR mixture increased the cellulose content to 10.939 % and decreased the lignin and pectin content to 71.261 % and 55.046 %, respectively. Whereas, AN:TR mixture increased the cellulose content to 12.572 % and decreased the lignin and pectin content to 69.941 % and 52.294 %, respectively. Afterward, the result of enzymatic hydrolysis with 3 g of Tween 80 and biological hydrolysis showed increasing of reducing sugar yield of 0.5831 and 0.0341 %, respectively. Further investigation was described as the crystallinity index and the fructose, glucose, and sucrose contents. The addition of both PEG 4000 and Tween 80 as a surfactant in the enzymatic hydrolysis process could significantly increase the concentration of reducing sugar.