Degradation of chlorophenolic compounds byTrichoderma harzianum isolated from Lake Bonney, south-eastern South Australia
✍ Scribed by van Leeuwen, J. A. ;Nicholson, B. C. ;Hayes, K. P. ;Mulcahy, D. E.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 103 KB
- Volume
- 12
- Category
- Article
- ISSN
- 1053-4725
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✦ Synopsis
In a study of the fate of chlorophenolic compounds in Lake Bonney, South-Eastern South Australia, several isolates of the fungus Trichoderma harzianum were assessed for their capacities to metabolize these compounds. Lake Bonney receives effluent from two pulp mills, one of which used molecular chlorine for bleaching of pulp between 1966 and September 1991. Effluent and waters of the lake had previously been found to be contaminated with chlorophenolic compounds, including 2,4,6-trichlorophenol and chloroguaiacols. Isolates of T. harzianum were obtained from lake water samples collected at locations approximately 10 m, 1, 5, and 9 km from the discharge point of effluent to the lake.
( ) The capacity of one isolate no. 1 collected 10 m from the discharge point, was assessed based on ( ) substrate loss in culture media, a corresponding reduction in adsorbable organic halogens AOX , production of 14 CO from a 14 C-labeled chlorophenol, and the release of chloride ions from the 2 dehalogenation of tetrachloroguaiacol. The capacities of several other isolates were briefly assessed based on reductions in concentrations of spiked tetrachloroguaiacol in culture medium and the corresponding AOX. ( ) ( ) Trichoderma harzianum No. 1 mineralized a minor percentage 2 -3% of spiked radiolabeled ( ) pentachlorophenol and partially dehalogenated 46% spiked tetrachloroguaiacol in mineral salts medium. All isolates were found capable of reducing concentrations of tetrachloroguaiacol in a mineral salts medium and the corresponding AOX. Those with the highest capacities were obtained from locations close to the effluent discharge point to the lake.
The presence of this fungus in lake water may account, in part, for the decline in chlorophenolic compounds in Lake Bonney after chlorination at the pulp mill had ceased.