Abstracts of the Articles Printed in Hakkokogaku Kaishi

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Effect of o-Phenylphenol on Escherichia coil-Phage Systems and Bacillus subtilis-Phage Systems. WEI-WE1 W u , 2 MICHIKO HISANO, ~ FUMIO KATO, 1 and AKIRA MURATA l * (Department of Applied Biological Sciences, Saga University, Saga 840, Japan, l and Department of Microbiology, Northwest University, Xian, People's' Republic of China 2) Hakkokogaku 67: 147-152. 1989.

We had found that o-phenylphenol (OPP) induced marked premature lysis of phage-infected cells in the Lactobacillus casei- phage J1 system. This paper describes the effects of OPP on Escherichia coil-phage systems (TI, T3, T4, T5, and ~5× 174) and Bacillus subtilis-phage systems (M2 and SPO1). OP P was bactericidal at 8-10 × 10 4 M. At these concentrat ions, it did not affect the infec- tivity of free phages or adsorpt ion of phages onto host cells. It in- hibited the growth of phages. The number of infective centers decreased with T4, T5, M2, and SPO1, but not with T1, T3, and ~× 174. OPP induced moderate premature lysis of cells infected with T4 and T5, while it inhibited the lysis of cells infected with T l , T3, and (h × 174. It induced mild lysis of cells infected with M2 and SPOI , but this was not specific for phage-infected cells.

* Corresponding author.

Toxic Effects of Mercuric Ion on the Growth of Chlorella sp. in In- organic Medium. TAKASH1 SHIRAKASHI,* HIROYUKI MATSUNAGA, KAZUO KAKn, and MiTsoo KURIYAMA (Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, Ishii-cho, Utsunomiya 321, Japan) Hakkokagaku 67: 153-158. 1989.

The toxicity of Hg 2+ for Chlorella sp. was studied using tur- bidimetry and viable cell counting. When the Chlorella cells were in- cubated in 22 m M phosphate buffer containing Hg 2+, the viable cell number decreased with increasing amoun t s of mercury volatilized. Upon the addition of 0.5 mg/I Hg 2. to the cell suspension (20 mg//) , the viable cell number decreased f rom 2 × 106 to 8 × l02 cells/ml after 70h of incubation. However, the turbidity of the cell suspension remained almost constant during the incubation period. Turbidity measurements showed a growth lag when the Chlorella cells pre- treated with Hg 2+ were transferred into inorganic medium supplied with CO2. Al though the lag time was prolonged with increasing Hg 2~ concentrat ions at pre-treatment , it was proved that the Chlorella cells grew immediately without lag by count ing viable cells. The lag time observed turbidimetrically was found to be a funct ion of the specific growth rate and the ratio o f survival in the inoculum. The length of lag time measured agreed well with that calculated f rom a derived equat ion using the specific growth rate ( B - 3 . 2 4 d 1) and initial viability (r°).

* Corresponding author.

Isolation of Sake-Yeast Strains Accumulating Large Amounts of Isoamyl Acetate. * TOSHIYASU YANAGIUCHI,* YOSHIFUM1 KIYOKAWA, and YOSHINORI WAKAI (Kizakura Sake Brewing Co., Ltd., 223, Shioya-cho, Fushimi- ku, Kyoto 612, Japan) Hakkokogaku 67: 159-165. 1989.

Isoamyl acetate is one of the most important component of a roma and flavour of sake. To increase the content of isoamyl acetate in fresh sake, we have selected mutan ts having low activity o f the esterase which hydrolyzes isoamyl acetate, by diazo staining of col- onies. One of the mutants , K-9Ha-3, had weak color by the diazo staining due to low esterase activity; it had low isoamyl acetate hydrolysis activity and accumulated a high content of isoamyl acetate in the mash. Thus , accumulat ion of isoamyl acetate depends on the ratio of alcohol acetyl t ransferase activi ty/ isoamyl acetate hydrolysis activity. We constructed diploids by hybridization between K-9Ha-3 and haploid clones isolated from an authentic brewing yeast, strain

433

Kyokai no. 10. The ability of fermentat ion of the diploids in sake moromi was superior to that of K-9Ha-3 and amino acid production by the diploids in sake moromi was lower than in the parental haploid yeasts. The mashes brewed by these diploids contain large amounts of isoamyl acetate.

* Corresponding author. t The Mechanism of Isoamyl Acetate Production by Sake-Yeast.

Continuous Glycerol Production with Yeast Cells, Saccharomyces uvarum, Immobilized with Agarose. KAZUHIRO YAMADE,* OSAMU NAKATA, and SusuMu FUKUSHIMA (Kan- sai University, Department of Chemical Engineering, Faculty of Engineering, 3-3-35 Yamate-cho, Suita, Osaka 564, Japan) Hak- kokogaku 67: 167-172. 1989.

Cont inuous glycerol production was examined in a bioreactor packed with immobilized yeast cells (Saccharomyces uvarum) with agarose. The op t imum pH value was 8.0 for adding sodium sulfite in feed solution. When the ethanol concentrat ion was 20-30 k g / m 3, the m a x i m u m yield o f glycerol f rom glucose was obtained. Using a feed solution containing 180 k g / m 3 of glucose and adding 100 k g / m 3 of sodium sulfite, 50 to 6 0 k g / m 3 of glycerol and 23 to 28 k g / m 3 of ethanol were obtained at the residence time of 40 h and a temperature of 303 K. The simulated values f rom immobilized yeast-cells proper- ties, which were activity, and yields of ethanol and glycerol f rom glucose in batch or cont inuous operation, almost agreed with the observed data in cont inuous operation.

* Corresponding author.

Fundamental Studies on the Use of the Iron-Oxidizing Bacterium Thiobacillus ferrooxidans. - - M o n o g r a p h - - TsuYosrn SUGIO (Division of Biological Function and Genetic Resources Science, Faculty of Agriculture, Okayama University, 1-1- 1 Tsushimanaka, Okayama 700, Japan) Hakkokogaku 67: 173-193. 1989.

The iron-oxidizing bacterium Thiobacillus ferrooxidans inhabits drainages in acid mines and plays a crucial role in the bacterial leaching of su l fde ores. The value of T. ferrooxidans in bacterial leaching may be due to the ability of this bacterium to oxidize both fer- rous ions and reduced sulfur compounds . To obtain more valuable strains for bacterial leaching, it is important to study the mechanism of iron- and sulfur-oxidation in T. ferrooxidans. The following findings are discussed in this paper. (i) A proteinous factor having a st imulating effect on iron-oxidizing activity was purified f rom T. fer- rooxidans grown on iron-salts medium. (ii) Novel sulfur- and sulfite- oxidizing enzymes, namely, sulfur: ferric ion oxidoreductase (SFORase) and sulfite: ferric ion oxidoreductase, were found in T. ferrooxidans, and the actual substrate during a solid sulfur oxidation by SFORase was identified. (iii) A new route for sulfur oxidation other than that previously reported was proposed in T. ferrooxidans, in which elemental sulfur is oxidized by the cooperation of three en- zymes, namely, SFORase, sulflte: ferric ion oxidoreductase, and iron oxidase, and Fe 3+ and Fe 2÷ act as mediators of electrons among these enzymes. (iv) Evidence that this new sulfur oxidation route is actually involved in aerobic sulfur oxidation by this bacterium is presented. (v) The mechanisms for the inhibition by Cu 2+ and Co 2÷ of the sulfur metabol ism of T. ferrooxidans, and the mechanisms for Mn 4. and Mo 6- reduction with elemental sulfur by T. ferrooxidans were clarified.

Measuring and Controlling in the Sake-Making Process. KAzuo SATO 1.~ and KYolcm KoNI)o 2 (National Research Institute oJ Brewing, 2-6-30 Takinogawa, Kita-ku, Tokyo 114, ~ and Hakutsuru Sake- Brewing Co. Ltd., 4-5-5 Sumiyoshi Minami-cho, Higashinada-ku, Kobe 658, 2 Japan) Hakkokogaku 67: 195-204. 1989.