Valorization of Soy Lecithin by Enzyme Cascade Reactions Including a Phospholipase A2, a Fatty Acid Double-Bond Hydratase, and/or a Photoactivated Decarboxylase.

A huge amount of phospholipids or lecithin is produced as a byproduct in the vegetable oil industry. However, most are just used as a feed additive. This study has focused on enzymatic valorization of lecithin. This was exploited by enzymatic transformation of soy lecithin into lysolecithin liposomes, including functional free fatty acids, hydroxy fatty acids, hydrocarbons, or secondary fatty alcohols. One of the representative examples was the preparation of lysolecithin liposomes containing secondary fatty alcohols [e.g., 9-Hydroxyheptadec-11-ene (9) and 9-heptadecanol (10)] by using a phospholipase A2 from Streptomyces violaceoruber, a fatty acid double-bond hydratase from Stenotrophomonas maltophilia, and a photoactivated decarboxylase from Chlorella variabilis NC64A. The engineered liposomes turned out to range ca. 144 nm in diameter by dynamic light scattering analysis. Thereby, this study will contribute to application of functional fatty acids and their derivatives as well as valorization of lecithin for the food and cosmetic industries.

Experimental study of fry-drying and melting system for industrial wastewater sludge.

In South Korea, ocean dumping of organic sludges has been prohibited by the London Convention and by Korean regulations. Therefore, the Government of South Korea has sought an alternative process for the disposal of organic sludges. Recently, the combined fry-drying and melting system has been recognized as an efficient way to utilize the energy content of organic industrial sludge. Three kinds of fry-dried industrial sludges (obtained from industrial sites DG, DJ and GM), which had average heating value of 20,470kJ/kg and less than 5% water content, were tested. Unlike sewage sludge, industrial sludge contains high concentrations of heavy metals and thus cannot be directly utilized as refuse-derived fuel. The dried sludges were melted in a furnace and then rapidly cooled to form vitrified slags; the vitrification of SiO2 securely encapsulates hazardous heavy metals within the crystalline structure of the slag. To evaluate the hazard of vitrified slag, the heavy metal elution concentration was analyzed. Following vitrification, Hg, Cd, Cr(+6), HCN and Pb concentrations were not detectable, whereas Cu concentration decreased from 26.78mg/L to 0.42mg/L in DJ sludge, from 27.10mg/L to 0.13mg/L in DG and from 49.47mg/L to 0.047mg/L in GM sludge.