Selective adhesion of wastewater bacteria to Pleurotus ostreatus mycelium in a trickle-bed bioreactor

Kateřina Svobodová,Denisa Petráčková,Čeněk Novotný,Hana Szabad

doi:10.3934/environsci.2016.3.395

Kateřina Svobodová, Denisa Petráčková + Show 2 more

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https://doi.org/10.3934/environsci.2016.3.395

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Abstract

The work is focused on spontaneous colonization of fungal mycelium by invading microorganisms in a trickle-bed fungal bioreactor operating under semi-sterile conditions. Pleurotus ostreatus was grown under the flow of synthetic wastewater containing activated sludge bacteria and the microbial consortium developed in the reactor was characterized. Genotype and phenotype profile of the reactor-invading, bacterial consortium was clearly distinctive from that of the original activated sludge. The bacterial consortium from the reactor contained a higher portion of bacteria capable of cellobiose utilization and a small amount of bacteria with the ability to utilize benzoic acids. The invading bacteria had no effect on the dye decolorization performance of the fungal reactor. Five bacterial strains colonizing P. ostreatus reactor cultures were isolated and identified as species of the genera Pseudomonas and Bacillus. Except for Bacillus cereus all strains displayed a potential to inhibit fungal growth on solid media (14 to 51 % inhibition) which was comparable or higher than that of the reference bacterial strains. The pH- and media composition-dependence of the growth inhibition was demonstrated.

Highlights

Biodegradation potential of white rot fungi was well established in previous two decades and various bioreactors based on fungal degradative power have recently been tested for biodegradation of persistent organic pollutants including synthetic dyes, chlorinated compounds, polycyclic aromatic hydrocarbons (PAHs), polybrominated flame retardants, or various pharmaceutics [1,2,3,4,5]
A freshly-grown, P. ostreatus mycelium immobilized on polyurethane foam (PUF) in a trickle-bed reactor was exposed to a flow of activated sludge organisms suspended in simulated wastewater (SWW) for 24 h (Table 1, Experiment 1)
The activated sludge removed from wastewater treatment plant (WWTP) was separated from the activated sludge liquid, washed with saline solution and suspended in sterile SSW to avoid the effects of nutrients and compounds present in the original activated sludge on the activated sludge/fungus interactions

Summary

Introduction

Biodegradation potential of white rot fungi was well established in previous two decades and various bioreactors based on fungal degradative power have recently been tested for biodegradation of persistent organic pollutants including synthetic dyes, chlorinated compounds, PAHs, polybrominated flame retardants, or various pharmaceutics [1,2,3,4,5]. Most of those studies were carried out under aseptic conditions in the laboratory and the fungal performance under non-sterile conditions is still poorly understood. Those studies only demonstrated the resulting changes in the biodegradation efficiency without providing information on the mechanisms involved in mutual interactions of the microorganisms

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