(602av) Waste From Beer Fermentation Broth; A Potent Source of Bioethanol and Hydrolyzing Enzymes

Waste from beer fermentation broth; A potent source
of bioethanol and hydrolyzing enzymes

Waleed
Ahmad Khattak, Mazhar Ul-Islam, Minkyung Kang, Joong Kon Park*

Department
of Chemical Engineering, Kyungpook National University, Daegu 702-701, Korea

(parkjk@knu.ac.kr)

Abstract

 A semi solid discharged residue produced
at the end of fermentation process, called as waste from beer fermentation
broth (WBFB) showed tremendous potential for bioethanol production without the addition
of saccharifying enzyme, microbial cells or carbohydrates. Number of
hydrolyzing enzymes produced from malt in beer fermentation broth during
brewing, were confirmed via sodium dodecyl sulfate polyacrylamide gel electrophoresis
(SDS PAGE) analysis. The enzymes extract from WBFB after partial purification
was evaluated for their hydrolyzing activities. Various parameters including
pH, temperature, thermal stability and buffer system was investigated for
hydrolyzing activities. With gradual increase in temperature (25-70°), the
presence of hydrolyzing enzymes in WBFB caused the degradation of yeast cell
wall and reduced the live cell density to a greater extent. However, elevated
temperature enhanced both the hydrolyzing activities and bioethanol production without
additional enzyme, microbial cells and carbohydrates along with shortening the
simultaneous saccharification and fermentation time. The enhanced bioethanol
production at elevated temperature seems to be partially resulted via cell free
enzymes system. Comparing to bare supernatant or sediments of the WBFB, the saccharification
and bioethanol production efficacy of original WBFB were superior.

Key words; Waste from beer fermentation
broth, Bioethanol, Hydrolyzing enzymes, Cell wall degradation, Cell free enzyme
system