Bacterial Degradation of Arylsulfonates in Treatment of Wastewater.

摘要

The river die-away test was used to study biodegradation of LAS (linear alkylbenzene sulfonates) detergents in natural waters. Samples of water from the Patuxent River at various seasons of the year contained organisms capable of degrading sodium dodecylbenzene sulfonate (DBS). Two pure cultures of LAS degraders were isolated and partially characterized. The culture from sewage was tentatively identified as a Moraxella species and the culture from river water as a Pseudomonas species. The cultures were shown to produce > 95% degradation of LAS added to culture media. The two cultures degraded dodecylbenzene sulfonate (DBS) and the LAS detergents present in commercial laundry preparations. Also,they were able to degrade the non-aromatic surfactant,sodium dodecylsulfate,but not the branched-chain ABS detergent. The two LAS degraders were not able to use as sole carbon source several simple aromatic compounds tested,such as p-hydroxybenzoate, m-hydroxybenzoate and L-phenylalanine. Also,they did not show growth with short chain sulfonates. They did,however,produce significant growth with butyl-,pentyl-,hexyl-and heptylbenzene sulfonate. Additional substrates or 'co-metabolites'were not required for LAS degradation by these cultures,nor did the presence of other nutrients significantly interfere with the process. The amount of oxygen consumed during degradation was less than would be expected for oxidation of both the side-chain and ring portions of the LAS molecule. These results are interpreted as meaning oxidative ring cleavage reactions are not carried out by these cultures.