Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Research Article J Mol Microbiol Biotechnol 2011;21:120–129 DOI: 10.1159/000331563 Heterologous Expression of Manganese Peroxidase in Aspergillus niger and Its Effect on Phenanthrene Removal from Soil Diana V. Cortés-Espinosa   a Ángel E. Absalón   a Noé Sanchez   a Octavio Loera   b Refugio Rodríguez-Vázquez   c Francisco J. Fernández   b a  Centro de Investigación en Biotecnología Aplicada del IPN, Carretera Federal Santa Inés, Tepetitla de Lardizabal, b  Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, and c  Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del I.P.N., Mexico, Mexico Introduction Polycyclic aromatic hydrocarbons (PAHs) are hydro- phobic compounds, and their persistence in the environ- ment is mainly due to their low water solubility [Cerni- glia, 1992]. Some of them are mutagenic and carcinogen- ic compounds, which emphasizes the importance of their removal from the environment [International Agency for Research on Cancer, 1983; Sudip et al., 2002]. Phenan- threne (Phe) is one of the several PAHs that are common- ly found as pollutants in soils [Chen et al., 2004; Jones et al., 1989], estuarine waters, sediments, and other terres- trial and aquatic sites [Shiaris, 1989]. Phe has been shown to be toxic to marine diatoms, gastropods, mussels, and fish [Black et al., 1983; White, 1986]. Phenanthrene, like all PAH, is biodegraded by enzymatic systems of fungi and bacteria [Cerniglia, 1992 and 1997]. Therefore, these microorganisms have been extensively studied for their application in bioremediation systems of contaminated soils [Aitken et al., 1998; Bezalel et al., 1996a; Dean-Ross et al., 2002; Haritash and Kaushik, 2009; Müncnerova and Augustin, 1994; Potin et al., 2004; Veignie et al., 2004]. Most studies using fungi for bioremediation have fo- cused on white rot fungi, particularly Phanerochaete Key Words Aspergillus niger  Heterologous expression  Manganese peroxidase  Phenanthrene  Soil remediation Abstract A strain of Aspergillus niger , previously isolated from sugar- cane bagasse because of its capacity to degrade phenan- threne in soil by solid culture, was used to express a man- ganese peroxidase gene (mnp1) from Phanerochaete chry- sosporium, aiming at increasing its polycyclic aromatic hydrocarbons degradation capacity. Transformants were se- lected based on their resistance to hygromycin B and the discoloration induced on Poly R-478 dye by the peroxidase activity. The recombinant A. niger SBC2-T3 strain developed MnP activity and was able to remove 95% of the initial phen- anthrene (400 ppm) from a microcosm soil system after 17 days, whereas the wild strain removed 72% under the same conditions. Transformation success was confirmed by PCR amplification using gene-specific primers, and a single frag- ment (1,348 bp long, as expected) of the recombinant mnp1 was amplified in the DNA from transformants, which was ab- sent from the parental strain. Copyright © 2012 S. Karger AG, Basel Published online: January 31, 2012 Francisco J. Fernández Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa San Rafael Atlixco no. 186, Col. Vicentina 09340 Mexico, D.F. (Mexico) Tel. +52 55 5804 6453, E-Mail fjfp  @  xanum.uam.mx © 2012 S. Karger AG, Basel 1464–1801/11/0214–0120$38.00/0 Accessible online at: www.karger.com/mmb