Journal of Biotechnology 116 (2005) 369–378 Application of Aspergillus niger-treated agrowaste residue and Glomus mosseae for improving growth and nutrition of Trifolium repens in a Cd-contaminated soil A. Medina, N. Vassilev, J.M. Barea, R. Azc´ on ∗ Departamento de Microbiolog´ ıa del Suelo y Sistemas Simbi ´ oticos, Estaci ´ on Experimental del Zaid´ ın, CSIC, Profesor Albareda 1, 18008 Granada, Spain Received 3 May 2004; received in revised form 15 December 2004; accepted 20 December 2004 Abstract The microbial transformation of sugar beet (SB) agrowaste with or without rock-phosphate (RP) has utility for the improve- ment of plant growth in a Cd (5 gg -1 ) artificially contaminated soil, particularly when the soil is co-inoculated with arbuscular mycorrhizal (AM) fungus Glomus mosseae isolated from a Cd-polluted area. Under such Cd-polluted conditions, the limited growth, mineral nutrition, symbiotic developments (nodulation and AM-colonization) and soil enzymatic activities were stimu- lated using SB or SB + RP as soil amendments and G. mosseae as inoculant. G. mosseae enhanced plant establishment in a higher extent in amended soil; it is probably due to the interactive effect increasing the potential fertility of such compounds and its ability for decreasing Cd transfer from soil to plant. The amount of Cd transferred from soil solution to biomass of AM-colonized plants ranged from 0.09 g Cd g -1 (in SB + RP-amended soil) to 0.6 g Cd g -1 (in non-amended soil). Nodule formation was more sensitive to Cd than AM-colonization, and both symbioses were stimulated in amended soils. Not only AM-colonization but also amendments were critical for plant growth and nutrition in Cd-polluted soil. The high effectiveness of AM inoculum increasing nutrients and decreasing Cd in amended soil indicated the positive interaction of these treatments in increasing plant tolerance to Cd contamination. © 2005 Elsevier B.V. All rights reserved. Keywords: Amendments; Cd contamination; Glomus mosseae; Rhizobium ∗ Corresponding author. Tel.: +34 958 18 16 00x298; fax: +34 958 12 96 00. E-mail address: rosario.azcon@eez.csic.es (R. Azc ´ on). 1. Introduction Elevated concentrations of heavy metals in soil from anthropogenic sources (fertilizers, amendments) or mining activities (Shetty et al., 1995) poses long- term risk to environmental and sustainable production. 0168-1656/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jbiotec.2004.12.009