Kotoyoshi Nakanishi

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.

Production of 3-hydroxypropionaldehyde in silage inoculated with Lactobacillus coryniformis plus glycerol.

We examined the production of an antimicrobial component, 3-hydroxypropionaldehyde (3-HPA), in laboratory-scale silage inoculated with Lactobacillus coryniformis strain 394, which ferments glycerol to 3-HPA. A modified colorimetric method that used an NaOH-treated blank and determined the absorption spectrum of the samples was employed to detect a 3-HPA-like component (HLC) that was assumed to be 3-HPA. Inoculation with Lb. coryniformis 394 plus glycerol in ensiling produced HLC at 10–460 ppm and contributed to inhibition of butyric fermentation and retardation of aerobic spoilage. HLC was considered to be 3-HPA from its absorption spectrum. These results suggest that the production of 3-HPA by Lb. coryniformis 394 is useful in ensiling and that the modified colorimetric method is effective to detect 3-HPA in silage.

Comparison of xylan and methyl β-xyloside-induced xylanases from Streptomyces sp

Three xylanases induced by xylan from Streptomyces sp. no. 3137 were purified to homogeneity. The enzymatic, physicochemical, and immunological properties of the enzymes were compared with those of three xylanases induced by non-metabolizable methyl β-xyloside. It was found that each xylanase produced under different culture conditions showed very similar properties.

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.