Assessment of the Biodegradability of Dialkyldimethylammonium Salts in Flow Through Systems

摘要

A bacterium capable of utilizing the alkyl chains of didecyldimethylammonium salt was isolated from activated sludge. In addition, the isolate also utilized didodccyldimethylammonium salt, ditetradecyldimethylammonium salt and alkyltrimethylammonium salts (C_(10) to C_(18)) as sole source of carbon and energy. The broad substrate with respect to the alkyl chain length was also demonstrated with oxidation rales of various quaternary ammonium salts by didecyldimethylammonium chloride-grown cells. The oxidation rate decreased with increasing alkyl chain lengths. The main factor impeding the biodegradation of dialkyldi-methylammonium salts with long alkyl chains is probably the low bioavailability of water-insoluble chemicals. The biodegradability of dialkyldimethylammonium salts was therefore determined in flow-through columns at concentrations below their aqueous solubility. Dialkyldimethylammonium salts adsorbed on silica gel particles packed in Bow-through columns were immediately metabolized by the isolate when dissolved. Microorganisms present in river water pumped through a sterile column degraded dissolved dicocodimethylammonium salts within a week.