Fungal biodegradation and detoxification of cork boiling wastewaters

The ability of several fungal strains to degrade and to detoxify cork boiling wastewaters was investigated. The fungal strains used in this work were Sporothrix sp., Trichoderma koningii, Chrysonilia sitophila and Penicillium glabrunt isolated from cork bark as well as Fusarium flocciferum and Phanerochaete chrysosporium. The results obtained in the degradation experiments carried out with each fungus showed that all fungi display similar abilities, with a chemical oxygen demand reduction of 54.2% (+/-4.7%) attained within five days of incubation. F flocciferum presented the highest value for the reduction of chemical oxygen demand of 62%. In addition, a rise in pH values of around 3 units was detected with all the strains, except for Penicillium glabrum. Toxicity tests performed on Vibrio fischeri revealed that fungal treatment of the wastewaters causes the complete loss of toxicity in the cases of Sporothrix sp., T koningii, P chrysosporium and F flocciferum. The other two tested strains were also able to detoxify the raw wastewaters, causing a ten-fold decrease in toxicity. ne results obtained in sequential biodegradation experiments with different pairs of fungi showed that although the increment in the COD reduction did not exceed 10%, an important reduction in toxicity and a pH rise were attained.