Hiroharu Tokuda

Effect of electric current on growth and alcohol production by yeast cells

The effects of electric current on the fermentation characteristics of yeast were investigated. When 10 mA direct current (DC) or 100 mA alternating current (AC) was applied to the culture broth, significant increases in cell growth and alcohol production rates occurred. The contents of higher alcohols, esters and organic acids in the culture broths to which AC and DC were applied, were different from those in the control culture (no current application). Several compounds such as acetaldehyde and acetic acid, were formed from ethanol as a result of electrode reaction.

Characteristics of non-woven fabrics as support materials for the immobilization of mycelia

Some properties of a non-woven fabric as a support for mycelia immobilization and characteristics of a immobilized mycelia prepared by gas phase cultivation method were examined. Water permeability and water absorbing capacity of the non-woven fabric were second highest among those of supports used in this study. Air permeability of the non-woven fabric was nearly equivalent to those of other supports. The adsorption rate of the proteins was higher in Bio-cube and non-woven fabric A 6. The gas phase cultivation method was applicable to immobilize some mycelia, which could not be immobilized by the liquid phase cultivation method. Furthermore, the productivity of xylanolytic enzyme, amylase and a-glucosidase of Aspergillus sp. immobilized by the gas phase cultivation method were higher than those obtained by liquid culture.