The Effect of Soluble Organic Matter on the Utilization of Phenoxy Herbicides by Pseudomonas sp.

摘要

Eight organisms of the genus Pseudomonas were isolated from soil and water samples by conventional enrichment techniques. They were used to compare the microbial degradation of the three phenoxy herbicides: 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenocyacetic acid (2,4,5-T),and 2-(2,4,5-trichlorophenoxy)-propionic acid (2,4,5-TP). 2,4,-D was readily attacked in a mineral salts medium by cultures adapted to this compound. The same concentrations of 2,4,5-T and 2,4,5-TP,however,were attacked only in the presence of a compound such as sodium benzoate,which served as a growth substrate. A comparison of cultures grown on benzoate and an herbicide,and on benzoate alone,showed no difference in cell yield. This suggests that no carbon or energy for growth was obtained from herbicide utilization,which is characteristic of cometabolism.