Bioremediation of CCA-Treated Wood By Brown-Rot Fungi Fomitopsis Palustris, Coniophora Puteana, and Laetiporus Sulphureus
Kartal, S. Nami
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This study evaluated oxalic acid accumulation and bioremediation of chromated copper arscnate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris Coniophora puteane, and Laetiporus sulphureas. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. polustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2g/l and 3.2g/l for these fungi, respectively. Fomitopsis palustris and L. sulohureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85% respectivcly: however. C. puteane remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palutris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureaus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.