Phytoremediation of soils co-contaminated by organic compounds and heavy metals: bioassays with Lupinus luteus L. and associated endophytic bacteria.

In the central part of the Iberian Peninsula there are old sealed landfills containing soils co-contaminated by several heavy metals (Cu, Zn, Pb, Cd, Ni, As, Cr, Fe, Al, Mn) and organic pollutants of different families (hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pesticides and other organochlorinated compounds, phenols and volatile compounds), which this work will address. We have focused on phytoremedial plants that are able to deal with this type of complex pollution, not only species that tolerate the joint effect of heavy metals in the soil, but also those that can take advantage of associated bacteria to efficiently break down organic compounds. This study was carried out with Lupinus luteus and its endophytes in two greenhouse experiments: A) growing in a substrate artificially contaminated with benzo(a)pyrene (BaP), and B) using real co-contaminated landfill soils.

Ecotoxicological diagnosis of a sealed municipal landfill.

Assessing the environmental impact of a soil-topped landfill requires an accurate ecotoxicological diagnosis. This paper describes various diagnostic protocols for this purpose and their application to a real case: the urban solid waste (USW) municipal landfill of Getafe (Madrid, Spain). After their initial sealing with soil from the surroundings about 20 years ago, most USW landfills in the autonomous community of Madrid have continued to receive waste.

Influence of xenobiotic contaminants on landfill soil microbial activity and diversity.

Landfills are often the final recipient of a range of environmentally important contaminants such as hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). In this study the influence of these contaminants on microbial activity and diversity was assessed in a municipal solid waste (MSW) landfill placed in Torrejón de Ardoz (Madrid, Spain). Soil samples were collected from four selected areas (T2, T2B, T8 and T9) in which the amount of total hydrocarbons, PAHs and PCBs were measured.

Biological upgrading of wheat straw through solid-state fermentation with Streptomyces cyaneus.

The biological upgrading of wheat straw with Streptomyces cyaneus was examined through the analysis of chemical and structural changes of the transformed substrate during solid-state fermentation. Analysis of enzymes produced during the growth of S. cyaneus showed that phenol oxidase was the predominant enzyme.

Chemical characterization and spectroscopic analysis of the solubilization products from wheat straw produced by Streptomyces strains grown in solid-state fermentation.

The effects of two extraction procedures on the yield and properties of APPL (acid-preciμltable polymeric lignin, or solubilized lignocellulose) produced by four streptomycetes during growth in solid-state fermentation were examined. When APPL was extracted with NaOH (0.1 M) rather than distilled water, yields increased threefold, with exhibiting maximum solubilization levels [163 mg product (g straw)].