DECOMPOSITION OF SURFACTANTS BY BACTERIA 73 Tablelfi Decomposition of Surface Active Agents (S.A.A.) S.A.A. Strain Polysor- Polysor- HCO ,1 HCO ,2 Oleth- Se *3 bate-20 bate-80 40 60 15 2020 J 77801 .4-J-. + + + ñ -- 78231 + + + + ñ -- 78718 + + + + ñ -- Pseudomonas 78755 + + + + ñ -- 771105 + + + + ñ -- 781215 + -H- + + ñ -- W-13 781014 .... ñ -- ß 1 HC040 Polyoxyethylene(40) Hydrogenated Castor Oil ß 2 HCO 60 Polyoxyethylene(60) Hydrogenated Castor Oil ß 3 Se 2020 Polyoxyethylene(20) 2-Octyl dodecyl Ether The growth curve of IV-6 group and IV-13 group The growth curve of strain 77801 (W-6 group) and the strain 77604 (W-13 group) at 25øC were shown by using Biophotometer (Jouan, France, and Figure 4). The 1ogarithimc growth of strain 77801 started rapidly after a lag of 16 hr. On the other hand, the logarithmic growth of strain 77604 was found to be slow after a long lag of 40 hr. The strain grew more slowly than strain 77801. o u 10 4- X•••/cm2 600/zw/cm 2 lO 1700/z w/cm 2 30 6'0 Reaction time 1200/z w/cm • Minutes Figure 6. Germicidal effect of U.V. lamp

74 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The effect of temperature on the growth of the bacteria The optimum temperature for the growth of the bacteria incubated in C.P.S. media for 2 weeks, was examined by a temperature gradient incubater (Toyo Kagaku Sangyo Co., Ltd.). Strain 77801 has optimum temperature between 25øC and 30øC and increased rapidly at 26øC-30øC in 24 hr. (Figure 5). But its growth was depressed at less than 11øC. Strain 77604 has optimum temperature between 22øC and 30øC. The strain was able to grow at a wide range of temperature, even between 6øC-10øC at which range strain 77801 was not able to grow. When the two strains were inoculated to C.P.S. agar and incubated at 0øC for 3 weeks, strain 77604 was observed as a colony, while strain 77801 was not recovered at all. Therefore, it is considered that strain 77604 existing indigenously in D.W. is a psychrophilic bacterial species. Consequently, various bacteria survive in purified water and their flora is changed by the influence of temperature. W-13 group (strain 77604) is psychrophilic and has a long lag time at 25øC, that is, it is not able to grow rapidly. This is the main reason why W-13 group is not able to be predominant in every purified water. W-6 group can grow rapidly in oligotrophic purified water at 20øC-30øC. Considering that the water temperature of the storage tanks in the plants is at 10øC-20øC in winter and 20øC-30øC in summer, we can assume that almost all the storage tanks are contaminated with W-6 group. The morphological and biochemical characterization of IV-6 group As W-6 group was observed predominantly in D.I.W., its representative type strain of W-6 group, sp.77801 was examined for taxonomical characterization. The colony of this strain on C.P.S. agar was circular with white to pale brown colour. Through microscopic examination of cells, they were identified as gram negative rods (0.4 to 0.8 by 1.0 to 2.0 microns). Flagella stain revealed the cells with polar flagella. In biochemical tests, the strain was positive for catalase and oxidase activities, while negative for the production of indole, starch hydrolysis and fluorescent pigmentation. TableW Germicidal Effect of Heating and Antibacterial Agent Heat Antibacterial Strains 5ooc 6ooc Agents* 20min. 0 5min. 10min. 1 day 2days 77801 Jr Jr .... 78231 --I- + .... 78718 Jr Jr .... Pseudomonos 78755 Jr Jr .... 781215 -I- -i- .... 771105 -I- Jr .... W-13 781014 Jr Jr .... Deionized water 4 x 105/ml 10 •10 *,J' Ethyl Alcohol 10% 1, Methyl Paraben 0.1%