Hitoshi Izumida

Continuous ethanol fermentation in molasses medium using Zymomonas mobilis immobilized in photo-crosslinkable resin gels

Abstract Zymomonas mobilis B-69 147, an ethanol-producing bacterium, was immobilized in photo-crosslinkable resin gels to form a biocatalyst system. Continuous ethanol fermentation with this immobilized Zymomonas was carried out in molasses and compared to that with immobilized yeast. As a result of operating this process for two weeks, a productivity of 60 g/l·h based on immobilized gel was obtained with improvement in the poor tolerance to salts of Zymomonas. The productivity of immobilized Z. mobilis was superior to that of immobilized yeast.

Characteristics of Zymomonas mobilis immobilized by photo-crosslinkable resin in ethanol fermentation

Abstract Zymomonas mobilis , an ethanol-producing bacterium, was immobilized in hydrophilic photo-crosslinked resin gels to form a biocatalyst. The molecular structure of the photo-crosslinkable resin could be modulated so as to minimize a disadvantage of this bacterium—poor-tolerance to salts in molasses. Characteristics of Z. mobilis immobilized by photo-crosslinkable resin gel, such as fermentability, cell growth in gel, the potential of gel materials, diffusion of materials, and salt distribution are discussed. ENTG-3800 photo-crosslinkable resin was selected as the most suitable entrapping material for Z. mobilis , especially in using molasses.