Interactions between a soil fungus,Trichoderma harzianum, and IIb metals—adsorption to mycelium and production of complexing metabolites
✍ Scribed by C. Krantz-Rülcker; B. Allard; J. Schnürer
- Publisher
- Springer Netherlands
- Year
- 1993
- Tongue
- English
- Weight
- 526 KB
- Volume
- 6
- Category
- Article
- ISSN
- 1572-8773
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✦ Synopsis
Fungi are capable of accumulating metals and, in soil, such accumulation may influence metal speciation and transport. The interactions between a common soil fungus, Trichoderma harzianum, and IIb elements were studied in the present investigation. The accumulation of the metals zinc, cadmium and mercury by starved and non-starved mycelium at different pH was determined by a batch technique using radioactive tracers; uptake of the metals was found to be large, with respective distribution coefficients of about 103"5, 10 z'5 and 104.0 for zinc, cadmium and mercury, respectively. Metal accumulation by a starved system was largely independent of pH in the range 3-9, where in a non-starved system an increased accumulation of zinc (at 10 -8 M) was observed at low pH (3-5). Potentiometric titrations performed on the two systems revealed significant differences in acid capacities, i.e. values close to zero for the starved system and 500-800 meq kg -1 for the non-starved system. The maximum metal uptake was at least 50 mmol kg -1 at pH 6.5 (calculated from adsorption isotherms). The present findings suggests that in the non-starved system a metabolite is produced and then released when the pH is within a certain range.