We have developed a rapid colorimetric method of glycoanalysis based on lectin-mediated aggregation of gold nanoparticles modified with glycoprotein. Gold nanoparticles (AuNPs) were surface-modified with a model mannose-rich glycoprotein, bovine lactoferrin (bLf), containing glycans that are accessible for lectin binding even after immobilization. In the presence of concanavalin A (Con A), the bLf-modified gold nanoparticles (bLf-AuNPs) spontaneously aggregated due to mannose-Con A interactions. This aggregation induced a significant red shift in the absorption band of the bLf-AuNPs in the visible region, which was detectable even by the naked eye. Dissociation constants (K_d) for the glycan-lectin interactions were calculated based on a computer simulation of UV-vis spectral titration. The K_d values obtained were considerably lower than those of monosaccharides, demonstrating a glycoside cluster effect in the glycan-lectin interactions. This method has advantages over other methods of glycoanalysis, including easy work-up, rapid detection, and the possibility of characterizing glycans attached to proteins through the use of a wide variety of lectins. Furthermore, the lectin-induced aggregation technique may be used for detection not only of glycoprotein glycans but also of unknown lectin-like receptors.

　To examine a method for producing Japanese spirits (shochu) from cheese whey-based fermentation broth, we evaluated the ethanol production by simultaneous saccharifying fermentation using Kluyveromyces marxianus KD-15 released from catabolite repression. The rice koji obtained by growing Aspergillus luchuensis or A. oryzae was mixed in combination with each yeast strain of K. marxianus NBRC1963 (wild strain), K. marxianus KD-15 and Saccharomyces cerevisiae NBRC10515. The pH, α-amylase and glucose forming activities as well as the glucose, lactose and ethanol contents in cheese whey-based fermentation broth were determined for 21 days. The results showed that the production of ethanol by K. marxianus KD-15 in combination with either koji was significantly higher than that by other yeast strains and the level in combination with rice koji obtained by A. luchuensis was approximately 30% higher compared with others. The α-amylase and glucose forming activities tended to decrease during fermentation. Nevertheless, the total amounts of lactose consumption in the fermentation broth using K. marxianus KD-15 were the highest even in combination with either koji, indicating that the improved ethanol production by K. marxianus KD-15 could be caused by its higher consumption ability of lactose derived from cheese-whey, but not of starch-derived glucose. These results show that K. marxianus KD-15 has high abilities of both cheese whey utilization and ethanol production even in the presence of mixture components including starch-degraded products, and is efficient for producing cheese whey-based Japanese spirits (shochu).