Mixed cultureFungal biofilmYeastsSynthetic dyesBiodegradation

The aim was to investigate the effect of yeast organisms on the degradation process by immobilized cultures ofligninolytic fungi. Immobilization was accomplished by 7-day colonization of polyamide mesh with mycelialfragments. Irpex lacteus decolorized N90% of the initial concentration of 150 mg l ?1 of anthraquinone RemazolBrilliant Blue R dye in three subsequent decolorization cycles and the degradation capacity was not negativelyaffected by the presence of 10 6 Saccharomyces cerevisiae cells per ml in the mixed culture. The yeast was notable to degrade the dye. I. lacteus biofilm was also resistant to bacterial infection with E. coli. Inoculation of theyeast to pre-formed I. lacteus biofilm culture resulted in a reduction of fungal biomass by 27%. Levels of LiP,MnP and laccase of I. lacteus were not much influenced by S. cerevisiae or E. coli. Similar resilience of P. ostreatusbiofilms was observed after exposure to yeast Issatchenkia occidentalis when the fungal degradation capacitymeasured with Reactive Orange 16 azo dye was maintained over two decolorization cycles. I. occidentalis didnot degrade the dye under the conditions used. Formation of densely packed fungal biofilms with abundant ex-tracellular polysaccharide was not impeded by the yeast. Increase of MnP and laccase levels attributable to thepresence of I. occidentalis was observed.