Studies related to biological detoxification of kraft pulp mill effluent. VII. The biotransformation of 12‐chlorodehydroabietic acid with mortierella isabellina

A detailed study of the biodegradation of one of the fish‐toxic chlorinated resin acids, 12‐chlorodehydroabietic acid (3), is discussed. When 3 is exposed to the fungus Mortierella isabellina, it is converted into the monohydroxylated metabolites 2α‐hydroxy‐12‐chlorodehydroabietic acid (5) and 16‐hydroxy‐12‐chlorodehydroabietic acid (8) after short‐term (26 h) incubation, and into the 2α, 16‐dihydroxy derivatives 11 and 14 after 96 h incubation. These metabolites show low levels of toxicity to fish.