Mobilizing agents enhance fungal degradation of polycyclic aromatic hydrocarbons and affect diversity of indigenous bacteria in soil

Authors

  • V. Leonardi,

    1. Dipartimento di Agrobiologia & Agrochimica, University of Tuscia, Via San Camillo De Lellis s.n.c., 01100 Viterbo, Italy; telephone: +39-0761-357368; fax: +39-0761-357242
    Search for more papers by this author
  • M.A. Giubilei,

    1. Dipartimento di Agrobiologia & Agrochimica, University of Tuscia, Via San Camillo De Lellis s.n.c., 01100 Viterbo, Italy; telephone: +39-0761-357368; fax: +39-0761-357242
    2. Dipartimento di Medicina Sperimentale & Scienze Biochimiche, University of Perugia, Perugia, Italy
    Search for more papers by this author
  • E. Federici,

    1. Dipartimento di Medicina Sperimentale & Scienze Biochimiche, University of Perugia, Perugia, Italy
    Search for more papers by this author
  • R. Spaccapelo,

    1. Dipartimento di Medicina Sperimentale & Scienze Biochimiche, University of Perugia, Perugia, Italy
    Search for more papers by this author
  • V. Šašek,

    1. Experimental Mycology Laboratory, Institute of Microbiology, Academy of Sciences of Czech Republic, Prague, Czech Republic
    Search for more papers by this author
  • C. Novotny,

    1. Experimental Mycology Laboratory, Institute of Microbiology, Academy of Sciences of Czech Republic, Prague, Czech Republic
    Search for more papers by this author
  • M. Petruccioli,

    1. Dipartimento di Agrobiologia & Agrochimica, University of Tuscia, Via San Camillo De Lellis s.n.c., 01100 Viterbo, Italy; telephone: +39-0761-357368; fax: +39-0761-357242
    Search for more papers by this author
  • A. D'Annibale

    Corresponding author
    1. Dipartimento di Agrobiologia & Agrochimica, University of Tuscia, Via San Camillo De Lellis s.n.c., 01100 Viterbo, Italy; telephone: +39-0761-357368; fax: +39-0761-357242
    • Dipartimento di Agrobiologia & Agrochimica, University of Tuscia, Via San Camillo De Lellis s.n.c., 01100 Viterbo, Italy; telephone: +39-0761-357368; fax: +39-0761-357242.
    Search for more papers by this author

Abstract

The impact of several mobilizing agents (MAs) (i.e., soybean oil, Tween-20, Tween-80, olive-oil mill wastewaters, and randomly methylated β-cyclodextrins) on the degradation performances of the white-rot fungi Irpex lacteus and Pleurotus ostreatus was comparatively assessed in a soil spiked with a mixture of seven polycyclic aromatic hydrocarbons (PAHs). Among the different MAs, soybean oil best supported the growth of both fungi that was twice that observed in soil in the absence of MAs. In addition, soybean oil positively affected PAH degradation by both fungi. In this case, the total weight of organic contaminants (TWOC) was lower than that in the absence of MAs (57.7 vs. 201.3 and 26.3 vs. 160.4 mg kg−1 with I. lacteus and P. ostreatus, respectively). On the other hand, the number of cultivable heterotrophic bacteria was significantly lower in the soil with soybean oil augmented with either one of the two fungi (5.21 vs. 8.71 and 0.22 vs. 0.51 × 107 CFU g−1 soil with I. lacteus and P. ostreatus, respectively). The effect of soybean oil was confirmed by denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes that showed a general decrease in biodiversity. The impact of the other MAs on bacterial diversity was either slightly negative or positive in incubation controls. Both richness and Shannon-Weaver index decreased upon treatment with P. ostreatus. Moreover, with this fungus the composition of the indigenous bacteria was not significantly affected by the type of MA used. By contrast, both indices increased in soil with I. lacteus in the presence of randomly methylated β-cyclodextrins (39 vs. 33 and 1.43 vs. 1.26, respectively) and soybean oil (19 vs. 5 and 1.01 vs. 0.65, respectively). Biotechnol. Bioeng. 2008;101: 273–285. © 2008 Wiley Periodicals, Inc.

Ancillary