Shiro Hanai

Identification of aromatic monomers in steam-exploded poplar and their influences on ethanol fermentation by Saccharomyces cerevisiae

Abstract Aromatic monomers in steam-exploded poplar were quantitatively analyzed and their influences on ethanol fermentation by the yeast Saccharomyces cerecisiae were studied. Most of the compounds inhibited the fermentation but the degree of inhibition greatly depended on the functional groups attached to the benzene ring. Their inhibitory values were estimated as follows: CHCH: +3.0,CHO: +1.5, p -OH: +1.0, COOH: +0.5, m -OH: 0, OCH 3 : −1.0.

Improvement of ethanol production of themophilic Clostridium sp. by Mutation

Abstract Three thermophilic Clostridium strains were isolated from soil as cellulose-fermenting bacteria wich produced ethanol, lactic acid, and acetic acid from cellulose at 60°C. To increase ethanol productivity, strains no. 187 was mutated with N-methyl-N′-nitro-N-nitrosguanidine. The resultant mutant, no 187-102-27, was superior to the original strain in ethanol production, and produced less lactic and acetic acid. The activities of some enzymes involved in the biosynthesis of the lactic and acetic acid of mutant no. 187-102-27 were lower than those of the original strain. These results are highly consistent with the acid production of the mutant strain being low.

Evaluation of ethanol productivity from cellulose by clostridium thermocellum

Abstract Clostridium thermocellum , a thermophillic anaerobe, directly converts cellulose to ethanol. To estimate its ethanol production from cellulose, we used a new method based on material balance by which the efficiencies of the enzymes that convert cellulose to ethanol were calculated. Using this method, the maximum efficiency of ethanol production of two strains of C. thermocellum was estimated to be 0.05, with 0.67 as the theoretical maximum.

Relationship between enzyme efficiency and alcohol concentration in Mirin mash

Abstract In mirin-making, the influence of alcohol concentration on enzyme activities that originated from koji and from enzyme preparations were analyzed quantitatively in order to determine the optimum concentration for production. The influences were complex. The efficiency of the enzymes in the mash with alcohol could be described by the ratio of the maximum digestibility, Dm, of the components in the raw materials to a constant, tm, which is related to the velocity (Eqs. 1 and 2). D=D m (1- exp (- T 30 t m )) D m t m = lim T 30 →0 d d t (D m (1- exp (- T 30 t m where T30 is the incubation time at 30°C, D is the digestion after T30, and Dm/tm corresponds to the enzyme activity, usually represented as the initial velocities of the enzymes. Analysis of Dm and tm made it possible to achieve maximum productivity in the making of mirin.