Mycelium-enhanced bacterial degradation of organic pollutants under bioavailability restrictions

Sungthong, R. , Tauler, M., Grifoll, M. and Ortega-Calvo, J.-J. (2017) Mycelium-enhanced bacterial degradation of organic pollutants under bioavailability restrictions. Environmental Science and Technology, 51(20), pp. 11935-11942. (doi:10.1021/acs.est.7b03183) (PMID:28921965)

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Abstract

This work examines the role of mycelia in enhancing the degradation by attached bacteria of organic pollutants that have poor bioavailability. Two oomycetes, Pythium oligandrum and Pythium aphanidermatum, were selected as producers of mycelial networks, while Mycobacterium gilvum VM552 served as a model polycyclic aromatic hydrocarbon (PAH)-degrading bacterium. The experiments consisted of bacterial cultures exposed to a non-disturbed non-aqueous phase liquid (NAPL) layer containing a heavy fuel spiked with 14C-labeled phenanthrene that were incubated in the presence or absence of the mycelia of the oomycetes in both shaking and static conditions. At the end of the incubation, the changes in the total alkane and PAH contents in the NAPL residue were quantified. The results revealed that with shaking and the absence of mycelia, the strain VM552 grew by utilizing the bulk of alkanes and PAHs in the fuel; however, biofilm formation was incipient and phenanthrene was mineralized following zero-order kinetics, due to bioavailability limitation. The addition of mycelia favored biofilm formation and dramatically enhanced the mineralization of phenanthrene, up to 30 times greater than the rate without mycelia, possibly by providing a physical support to bacterial colonization and by supplying nutrients at the NAPL/water interface. The results in the static condition were very different because the bacterial strain alone degraded phenanthrene with sigmoidal kinetics but could not degrade alkanes or the bulk of PAHs. We suggest that bacteria/oomycete interactions should be considered not only in the design of new inoculants in bioremediation, but also in biodegradation assessments of chemicals present in natural environments.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Sungthong, Dr Rungroch
Authors: Sungthong, R., Tauler, M., Grifoll, M., and Ortega-Calvo, J.-J.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Environmental Science and Technology
Publisher:American Chemical Society
ISSN:0013-936X
ISSN (Online):1520-5851
Published Online:18 September 2017
Copyright Holders:Copyright © 2017 American Chemical Society
First Published:First published in Environmental Science and Technology 51(20): 11935-11942
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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