• Journal of Life Science
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• v.22 no.4
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• pp.508-515
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• 2012

In this study, DEAE-cotton [derivatized by 2-(diethylamino)ethyl chloride hydrochloride (DEAE HCl)] was prepared as a carrier for immobilized $Pichia$ $stipitis$ for ethanol production. When cotton was derivatized with 0.5 M DEAE HCl, the yeast cell suspension was adsorbed at 100% of the initial cell $OD_{600}$. The adsorbed yeast cells were estimated to be 101.8 mg-dry cells/g-DEAE-cotton. In particular, when a flask culture using the immobilized yeast cells was conducted in a glucose and xylose-containing medium, the yeast cells on the DEAE-cotton gradually produced ethanol, according to glucose and xylose consumption; the ethanol yield was approximately 0.33 g-ethanol/g-monosaccharide. Because DEAE-cotton was successfully used as a carrier for ethanol production from a glucose and xylose-containing medium, we expect that this bioethanol production process may be used for the bioethanol production process from the hydrolysate of lignocellulosic biomass. All the results of DEAE-cotton were compared with those of DEAE-cellulose as a carrier for immobilization.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1434-1444
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• 2013

We established a two-step production process using immobilized S. cerevisiae and P. stipitis yeast to produce ethanol from seaweed (U. pertusa Kjellman) hydrolysate. The process was designed to completely consume both glucose and xylose. In particular, the yeasts were immobilized using DEAE-corncob and DEAE-cotton, respectively. The first step of the process included a continuous column reactor using immobilized S. cerevisiae, and the second step included a repeated-batch reactor using immobilized P. stipitis. It was verified that the glucose and xylose in 20 L of medium containing the U. pertusa Kjellman hydrolysate was converted completely to about 5.0 g/l ethanol through the two-step process, in which the overall ethanol yield from total reducing sugar was 0.37 and the volumetric ethanol productivity was 0.126 g/l/h. The volumetric ethanol productivity of the two-step process was about 2.7 times greater than that when P. stipitis was used alone for ethanol production from U. pertusa Kjellman hydrolysate. In addition, the overall ethanol yield from glucose and xylose was superior to that when P. stipitis was used alone for ethanol production. This two-step process will not only contribute to the development of an integrated process for ethanol production from glucose-and xylose-containing biomass hydrolysates, but could also be used as an alternative method for ethanol production.