Fungi from marine habitats: an application in bioremediation

Abstract

This paper synthesizes the work done on decolourization of bleach plant effluent and synthetic dyes using fungi from marine habitats. Three fungi obtained from marine habitats removed up to 60–95% of Kraft paper mill bleach plant effluent colour. One of the cultures could bring about decolourization of bleach plant effluent at an alkaline pH of 8.2. All the three fungi produced the lignin-modifying enzymes laccase and manganese-dependent peroxidase (MNP) and one of the cultures, Flavodon flavus (isolate 312), also produced lignin peroxidase (LIP) when grown in low nitrogen medium. Production of these enzymes increased in the presence of paper mill effluent in all the three isolates. Isolate Flavodon flavus (312) decolourized synthetic dyes like Azure B, Brilliant green, Congo red, Crystal violet, Poly-R, Poly-B and Remazol Brilliant Blue R in low nitrogen medium prepared with distilled as well as with artificial sea water. Decolourization of dyes was also observed in a rich nutrient medium like malt extract broth. About 60–90% of decolourization was achieved in these media within 3–10 days. Visible spectra of most of the dyes incubated with this culture indicated degradation at the end of the experiment. Manganese-dependent peroxidase enzyme was always produced in cultures of 312 containing dyes and in some cases, a direct correlation existed between % decolourization and MNP activity, suggesting its involvement in this process. This culture with its capacity to degrade paper mill effluent and synthetic dyes appears to be a potential candidate for bioremediation of coloured industrial effluents.