Daicel Chemical Industries, Ltd.

Godo Shusei Co., Ltd.

Shoichi Takao

Akinobu Matsuyama

Kimitoshi Kawai

Hiroshi Sasaki

Kazuhiko Kurosawa

Sadao Kageyama

Masahiko Sawada

Riboflavin is effectively obtained by culturing in a medium (1) a purine-requiring revertant derived from a riboflavin-producing yeast which belongs to the genus Saccharomyces and has a purine requirement or (2) a riboflavin-producing yeast which belongs to the genus Saccharomyces and is resistant to ammonium ion, and collecting the produced riboflavin.

Process for preparation of riboflavin

Riboflavin is obtained directly from the culture in a high yield by cultivating a riboflavin-producing microorganism in a medium using a lower (C.sub.1 to C.sub.4) aliphatic compound, separating riboflavin contained in the culture in the form of heated aqueous solution from solid matters, and crystallizing riboflavin from the heated aqueous solution. Riboflavin is also prepared in a high yield by cultivating a riboflavin-producing yeast belonging to the genus Saccharomyces which has purine requirements and/or resistance to 3-amino-1,2,4-triazole in a medium and collecting riboflavin formed and accumulated in the medium. Moreover, riboflavin is prepared in a high yield even in the presence of iron ions by preliminarily cultivating in liquid a riboflavin-producing yeast belonging to the genus Saccharomyces and then cultivating it in a riboflavin-producing medium containing zinc ions.

Process for the preparation of riboflavin

A method for the cooking-free saccharification of starch using an amylase produced by Corticium rolfsii AHU 9627 or its variants. According to the method, even a high viscous suspension of 10% (w/v) or more raw-corn starch is almost completely hydrolyzed within 8 hours. The saccharification is proceeded at a higher temperature and a lower pH compared with those in known methods utilizing other amylases which are able to hydrolyze uncooked starch, so that the propagation of the infectious bacteria which would affect the saccharifying efficiency can be avoided.

Method for direct saccharification of raw starch using enzyme produced

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Sapporo, Japan

Shoichi Takao