• Korean Chemical Engineering Research
• /
• v.45 no.3
• /
• pp.226-233
• /
• 2007

In this study, the effects of additives such as ionic surfactant and cosurfactant were studied on the solubilization of sulfur compounds contained in the crude oil by Tergitol series nonionic surfactants. It was found that the addition of an ionic surfactant such as sodium oleate, potassium oleate, CTAB and DTAB did not enhance solubilization capacity of Tergitol series nonionic surfactant. On the other hand, the addition of a long-chain alcohol as a cosurfactant increased the solubilization of sulfur compounds in the crude oil. The effect of alcohol was found to become reduced with an increase in the amount of crude oil used mainly due to partitioning phenomena of an nonionic surfactant. The enhancement of solubilizing capacity of Tergitol series nonionic surfactant with addition of a cosurfactant was associated with a decrease in interfacial tension between crude oil and surfactant solution. The pH of Tergitol nonionic surfactant solution did not affect the solubilization of sulfur compounds. Finally, it was found that the growth of sulfur reducing microoganisms was not greatly affected by both addition of nonionic surfactant and cosurfactant.

• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.400-406
• /
• 1997

Chemical composition and antimicrobial activity of Houttuynia cordata Thunb. were investigated to develop a natural food preservative from it. Aspartic acid, glutamic acid, glycine and arginine were major amino acids of Houttuynia cordata Thunb., but were present in a trace amount. Free sugars were composed of glucose, fructose, sucrose and maltose and major fatty acids were linolenic acid, linoleic acid, oleic acid, and palmitic acid. Mineral elements were potassium, calcium, magnesium, iron, zinc, and copper. Antimicrobial activities were shown in acidic, neutral and phenolic fraction of Houttuynia cordata Thunb., but not in basic fraction. Among the four fractions, neutral fraction showed the strongest antimicrobial activities against microorganisms tested, such as Pseudomnas aeruginosa, Micrococcus luteus, Bacillus subtilis, Aspergillus parasiticus and Aspergillus flavus. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of the neutral fraction varied according to microoganisms tested. The lowest values of MIC (0.0075 g eq./mL) and MLC (0.10 g eq./mL) were obtained from Pseudomonas aeruginosa.