. Can. J. Chem. 59,2334Chem. 59, (1981. A study related to biological detoxification of kraft pulp mill effluent is presented. A series of fungal and bacterial preparations were evaluated for their action on dehydroabietic acid (DHA), one of the effluent constituents toxic to fish. Mortierella isabellina was the organism selected for the biodegradation of DHA and subsequent chemical studies established the structures of four novel diterpenoid substances with very much lower acute toxicity to Daphnia pulex.
Mortierella isabeUina ATCC 38063 is a zygomycete capable of hydroxylating fish-toxic resin acids which occur in certain pulp mill effluents to nontoxic metabolites. Addition of dehydroabietic acid (1) (80 mg/liter) to a freshly inoculated culture of M. isabellina in dextrose-yeast extract broth resulted in precursor disappearance in 28 to 30 h. During growth phase, hydroxylation occurred at C-2, whereas hydroxylation at C-15 and C-16 commenced with onset of stationary phase. Alternatively, 1 added to stationary-phase culture (40 mg/liter) disappeared within 2 h and hydroxylation occurred concurrently at C-2, C-15, and C-16. Enzymatic activity of stationary-phase culture was totally cell associated and was present despite the absence of 1 during the preparatory growth phase. Resuspension of mature fungi as free mycelia or immobilized in calcium alginate beads did not diminish the effectiveness of the biotransformation, although two new metabolites, 15-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (5) and 16-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (7) were formed. Immobilized mycelia retained hydroxylase activity for >110 days whether or not they were challenged with fresh 1 on a regular basis. In this respect they are more long-lived than resuspended free mycelia are.
Some irone isomers with the natural chirality have been synthesised from (+)-citronella1 ( 7). (+)-Methyl citronellate (21 ) obtained from compound (7) was methylated stepwise to give methyl 2,2,3,7-tetramethyloct-6enoate (23). After hydrolysis of the ester (23), the resulting acid was converted into the corresponding acyl chloride, which was then cyclised by means of tin(lV) chloride to give 2,2,3-trimethyl-6-(1 -chloro-1 -methyl-ethy1)cyclohexanone ( 24). The cyclohexanone (24) was dehydrochlorinated, reduced, acetylated, and then ozonised to give 2-acetoxy-3,3,4-trimethylcyclohexanone (27). The Wittig reaction of the ketone (27) with methoxymethylenetriphenylphosphorane followed by hydrolysis and elimination of acetic acid provided 3,3,4trimethylcyclohexene-1 -carbaldehyde (28). The vinyl ether of an allylic alcohol obtained by reduction of the aldehyde (28) was thermolysed to give the key intermediate, 1 -(2,2,3-trimethyl-6-methylenecyclohexyl)acetaldehyde (1 3), stereoselectively. Elongation of the side-chain in ( 13) afforded (+)-trans-y-irone (32a) as the major product. Treatment of the irone (32a) with phosphoric acid yielded (-)-frans-cx-irone (2).
A study related to the biological detoxification of Kraft pulp mill effluent is presented. Several fungal and bacterial preparations were evaluated for their action on isopimaric acid (IPA). one of the effluent constituents toxic to fish. Mortierella i~ahellina was the organism selected for the biodegradation of IPA and subsequent chemical studies established the structures of three diterpenoid substances with very much lower acute toxicity.
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