MINERALIZATION OF 2,4-DICHLOROPHENOXYACETIC ACID (2,4-D) AND MIXTURESOF 2,4-D AND 2,4,5-TRICHLOROPHENOXYACETIC ACID BY PHANEROCHAETE-CHRYSOSPORIUM

Evidence is presented for mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) in nutrient-rich media (high-nitrogen and malt extract me dia) by wild-type Phanerochaete chrysosporium and by a peroxidase-nega tive mutant of this organism. Mass balance analysis of [U-ring-C-14]2, 4-D mineralization in malt extract cultures showed 82.7% recovery of r adioactivity. Of this, 38.6% was released as (CO2)-C-14 and 27.0, 11.2 , and 5.9% were present in the aqueous, methylene chloride, and myceli al fractions, respectively. 2,4-D and 2,4,5-trichlorophenoxyacetic aci d (2,4,5-T) were simultaneously mineralized when presented as a mixtur e, and mutual inhibition of degradation was not observed. In contrast, a relatively higher rate of mineralization of 2,4-D and 2,4,5-T was o bserved when these compounds were tested as mixtures than when they we re tested alone.