White-rot Fungal Cultures for Degradation of Water Soluble Pollutants: The Aspect of Bacterial Stress

Abstract

Potential of ligninolytic fungi to degrade organopollutants including synthetic dyes has been proven and the use of immobilized fungal cultures in semisolid state-, trickling-bedand rotating disk reactors for efficient biodegradation of textile dyes repeatedly shown. The effect of bacteria on fungal biofilms and their biodegradation efficiency treated in this study is a factor important in application of fungal cultures under nonsterile conditions. The results will demonstrate tolerance of highly degradative fungi Pleurotus ostreatus, Dichomitus squalens and Irpex lacteus to growth inhibition by coliform and soil bacteria on solid agar media. In static, liquid-medium cultures of I. lacteus working at pH 4.5 and 6.0 for 10 days, the capacity of decolorization of anthraquinone dye Remazol Brilliant Blue R (RBBR) was significantly inhibited by 105106 CFU of Escherichia coli but not Pseudomonas aeruginosa. No specific effect on ligninolytic enzyme production was observed. The presence of 109 CFU of E. coli in semisolid-state cultures of I. lacteus during a 4-week cultivation did not negatively influence the capacity of the fungus to decolorize RBBR. Bacterial counts increased during cultivation but fungal growth was not affected by the presence of the bacterium. Manganesedependent peroxidase was the main enzyme present. The enzyme levels exhibited variations attributable to the presence of the bacterium. Electron microscopy showed that fungal biofilms were dense and stable during long-term runs even in the presence of E.coli. Sustainability and efficiency of fungal biofilms in long-term biodegradation experiments was demonstrated. The work was supported by the projects IAAX00200901 and AV0Z50200510. Biography C. Novotny obtained Ph.D. at Charles University, Prague (1976). He is senior scientist at the Institute of Microbiology of the ASCR, v.v.i., Prague (1976-2010). He was head of Laboratory of Yeast Physiology (19811990) and Laboratory of Experimental Mycology (2002-2006). Topics of research are: microbial physiology, bioremediation and environmental biotechnologies. He has published 53 papers in impacted journals and is assistant editor of Folia Microbiologica.