Monday, April 30, 2007

Enzymatic hydrolysis and ethanolic fermentation of tobacco stalks and orange waste pretreated by wet oxidation

Carlos Martín1, Eugenio Carrillo1, Ariel García1, Teresa Fernández1, and Anne Belinda Thomsen2. (1) Department of Chemistry and Chemical Engineering, University of Matanzas, Matanzas 44740, Cuba, (2) Biomass for Energy and Materials, Risø National Laboratory, P.O.Box 49, DK-4000 Roskilde, Denmark

Wet oxidation (WO) was used as a pretreatment method prior to enzymatic hydrolysis of tobacco stalks and orange waste. The pretreatment, which was performed at 195oC, an oxygen pressure of 1.2 MPa, during 15 min, and in presence of Na2CO3, increased cellulose content of the materials and gave cellulose recoveries of approximately 90 %. The pretreatment enhanced the susceptibility of cellulose to enzymatic hydrolysis. The highest enzymatic convertibility, 64.9 %, was achieved for pretreated tobacco stalks. The ethanolic fermentation, using Saccharomyces cerevisiae, of WO filtrates was inhibited compared with the fermentation of a reference glucose solution. The inhibition was more remarkable for the filtrate of tobacco stalks than for that of orange waste. The volumetric productivity of ethanol was more inhibited (inhibition degree = 79.1-86.8%) than the ethanol yield (inhibition degree = 7.1-9.5%).

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