title: Effect of bacteria on the degradation ability of Pleurotus ostreatus.
abstract: White-rot fungi are efficient degraders of lignin whose extracellular enzymes have a potential to degrade organopollutants. In natural conditions these fungi enter into interactions with other organisms, which may affect their biodegradation capacity. The aim was to investigate the ability of Pleurotus ostreatus to form stable biofilms and to test the capacity of the fungus to degrade Remazol Brilliant Blue R in mixed cultures with bacteria. Bacterial counts were determined to see the behavior of the bacterium in the mixed culture with the fungus. In axenic conditions, the homogenized fungal mycelium was able to form an active biofilm which quickly degraded the dye. The addition of Pseudomonas fluorescens or Bacillus licheniformis bacteria at 106CFU·mL-1did not affect the decolorization rate by 7-d-old fungal biofilms where the decolorization rate reached 90%. In contrast, when fragments of the fungal mycelium were used for inoculation to pre-formed biofilm of P. fluorescens, the biofilm was allowed to develop for one week's time, no decolorization of RBBR was observed and low activities of MnP and laccase were detected. The use of agar disks covered with fungal mycelium for the inoculation to pre-formed biofilm of P. fluorescens resulted in a fully developed biofilm that decolorized RBBR with similar efficiency as the pure P. ostreatus. The difference between the agar-disk- and homogenized-mycelium inoculated fungal biofilms was corroborated by the measurement of total fungal biofilm biomass that was 6-fold lower in the latter biofilm. Capability of the fungus to overcome the competition of the bacterial biofilm thus depended on the type of fungal growth centres, where intact hyphae were superior to the fragments of mycelium. A similar effect was not observed with the biofilms of B. licheniformis where the bacterial growth was less massive. The ability of P. ostreatus biofilms to resist massive bacterial stress was demonstrated.
authors.affiliation: Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic. Electronic address: hana.valkova1@email.cz.
authors.forename: Hana
authors.initials: H
authors.lastname: Válková
authors.affiliation: Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic. Electronic address: novotny@biomed.cas.cz.
authors.forename: Čeněk
authors.initials: Č
authors.lastname: Novotný
authors.affiliation: Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic. Electronic address: Katerina.Malachova@osu.cz.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Malachová
authors.affiliation: Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic. Electronic address: Pavlina.Slosarcikova@email.cz.
authors.forename: Pavlína
authors.initials: P
authors.lastname: Šlosarčíková
authors.affiliation: Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic. Electronic address: jindrich.fojtik@seznam.cz.
authors.forename: Jindřich
authors.initials: J
authors.lastname: Fojtík
mesh_terms: D001419:Bacteria; D001673:Biodegradation, Environmental; D018441:Biofilms; D004396:Coloring Agents; D042845:Laccase; D008031:Lignin / Q000378:metabolism*; D020076:Pleurotus / Q000378:metabolism*
chemical_list: D004396:Coloring Agents; D008031:Lignin; D042845:Laccase
keywords: Anthraquinone dye; Bacillus licheniformis; Bacterial stress; Biodegradation; Fungal biofilms; Pseudomonas fluorescens