TITLE:
Effect of Heavy Metals on the Growth of Bacteria Isolated from Sewage Sludge Compost Tea
AUTHORS:
María Vela-Cano, Antonio Castellano-Hinojosa, Antonia Fernández Vivas, María Victoria Martínez Toledo
KEYWORDS:
Wastewater Sludge, Compost Tea, Minimum Inhibitory Concentration, Heavy-Metal Removal, Rhodococcus sp.
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.10,
August
19,
2014
ABSTRACT: The amount of urban sewage
sludge is increasing daily. For this reason, it is necessary to have an
environmentally friendly use for this residue. Land applications in olive grove
soil, poor quality soil, as a compost or a compost tea could be considered as one
of the best options, because it has a high content of organic matter. However,
the presence of heavy metals in some sewage sludge could be an environmental
problem. In this sense, the aim of this work is to check the tolerance of the
culturable microbiota present in sewage sludge compost tea to four heavy
metals, Cu, Cd, Pb and Zn. Among microbiota isolated, eight strains showed high
resistance to Pb, Zn, Cu and Cd, and one microbe (Rhodococcus sp.) showed a
special tolerance to every heavy metal. The strains were divided into six
genrera: Rhodococcus, Virgibacillus, Leifsoni, Achromobacter, Cupriavidus and Oceanobacillus sp. Finally, Rhodococcus sp. strain 3 was able to remove
different amounts of heavy metals from the culture media with intracellular and
surface accumulation of Cu, Zn, Pb and Cd. The application of this bacterial
strain in bioremediation processes is discussed.