A study of the microbial degradation of metal phthalocyanine textile dyes by high-performance liquid chromatography and atomic absorption

The investigation of the degradation of two commercially available dyes (Re mazol Turquoise Blue and Everzol Turquoise Blue) by the lignin-degrading fu ngus Phanerochaete chrysosporium and comparison with that of a phthalocyani ne whose structure is known (Heligon Blue) are presented. Atomic absorption showed a large release of copper from the biomass at day 7. Polarography s erved to speciate the copper present in the supernatant. Day 5 sees the com plete disappearance of the main dye peak with the release of free copper in to the supernatant. Day 7 sees a large increase in the free copper signal w ith two other electroactive species also present in the supernatant, all of which are seen to decrease at day 8. Visible spectroscopy shows that the m ain decolourization takes place between day 4 and day 6, with complete deco lourization occurring at day 7. HPLC analysis again confirms the above resu lts, with possible degradation products detected at 254 nm occurring at 3.6 21 and 4.170 min at day 7 which may well correlate with those found in pola rographic analysis at -1050 and -1150 mV. Day 7 also sees a large increase in a peak at 2.744 min. Copyright (C) 1999 John Wiley & Sons, Ltd.