DECOMPOSITION OF SURFACTANTS BY BACTERIA 75 BLANK HAZY PHENOMENON Figure 7. Hazy phenomenon of Lotion A The strain was also positive for citrate utilization, gelatin hydrolysis, nitrate reduction and urease activity tests. Considering the results of the biochemical tests, strain 77801 was identified as belonging to the genus Pseudomonas by Bergey's manual eighth edition, and it is considered that indigenous W-6 group from D.I.W. belong to the same genus. The decomposition of S. A.A. The decomposition of S.A.A. used in toilet waters, was carried out by using the bacteria being predominant in the tanks (Table III). Polysorbate-20, polysorbate-80, H.C.O.-40 and H.C.O.-60 (ester-type) were easily decomposed by Pseudomonads isolated from the storage tanks. Ps.sp. 77801 was found to decompose the polysorbate- type more easily than H.C.O.-type among ester-type S.A.A. Seodol 2020 © (ether-type) was not decomposed by these bacteria. On the other hand, strain 781014 (W-13 group) was not able to decompose S.A.A. As there are a variety of bacteria capable of decomposing S.A.A. in the storage tanks, it is possible that cosmetics are degraded because of these water contaminants. Accordingly, the effect of U.V. lamps, heat and antibacterial agents on these bacteria was examined. The effect of U. V. lamp, heat and antibacterial agents on the bacteria The tests were carried out in glass cylindrical tank (radius 18 cm, height 41 cm, volume 8 liters) with a U.V. lamp immersed in the center of water. U.V. irradiation was definitely effective in reducing the number of bacteria in D.I.W. (Figure 6). D.I.W. with 105/ml bacteria was reduced to less than 10/ml by the irradiation of the U.V. lamp at 1200/xw/cm 2 for 60 min or at 1700/xw/cm 2 for 30 min. The effect of heating and antibacterial agents were shown in Table IV. All the predominant bacteria isolated from the storage tanks were not killed at 50øC for 20

76 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TableV Turbidity of Lotion A* 50øC Strain 1 Day 2 Days 3 Days 77801 % -H- • 78231 -- + • Psuedomonas 78718 + • • 78755 + + • *Ingredients of Lotion A 95% Ethyl Alcohol 10ml Glycerol 1 ml Polysorbate-20 0.1 g Methylpa raben 0.1 g Sterile deionizedwater 100ml min, but killed at 60øC for 5 min. Although not shown in Table IV, only one strain out of 72 strains isolated from D.I.W. was not killed, the death-rate was almost 99% at 60øC for 5 min. It is considered that almost all the bacteria in D.I.W. were killed at 60øC for 5 min because they were nonspore forming, gram-negative rods. The effect of antibacterial agents on the bacteria was also examined (Table IV). All the predominant bacteria isolated from the storage tanks were killed by the antibacterial agents (ethyl alcohol 10% and methylparaben 0.1%). -r i----I 25øC, 3days O o • 25øC, 7days Z z 100- o o 50. CPS I Nutrient Endocellular CPS Nutrient Extracellular Activity of Enzyme CPS I Total Nutrient Figure 8. Enzyme activity of Ps. sp. 77801