Heavy metal ion influence on the photosynthetic growth of Rhodobacter sphaeroides.
The potential of purple non-sulphur bacteria for bioremediation was assessed by investigating the ability of Rhodobacter sphaeroides strain R26.1 to grow photosynthetically in heavy metal contaminated environments. Bacterial cultures were carried out in artificially polluted media, enriched with the transition metal ions Hg2+, Cu2+, Fe2+, Ni2+, Co2+, MoO4(2-), and CrO4(2-) in millimolar concentration range. For each investigated ion the effect on growth parameters was evaluated. The analysis of concentration-effect curves revealed a differentiated response, indicating that diverse mechanisms of tolerance and/or resistance are involved. Adaptation or selection procedures were not applied, leading to assess intrinsic abilities of coping with these contaminants. The microorganism proved to be highly tolerant to heavy metal exposure, especially towards Co2+, Fe2+ and MoO4(2-). In addition Ni2+ and Co2+ were found to decrease the cellular content of light harvesting complexes. A characteristic behavior was observed with mercuric ions, which produced a significant increase of the lag-phase.
Giotta
Livia
L
Dipartimento di Scienza dei Materiali, Università degli Studi di Lecce, strada per Arnesano, 73100 Lecce, Italy. livia.giotta@unile.it
Agostiano
Angela
A
Italiano
Francesca
F
Milano
Francesco
F
Trotta
Massimo
M
D001673:Biodegradation, Environmental; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000032:analysis* / Q000633:toxicity; D019216:Metals, Heavy / Q000032:analysis* / Q000633:toxicity; D010788:Photosynthesis / Q000187:drug effects*; D012242:Rhodobacter sphaeroides / Q000254:growth & development*
D004785:Environmental Pollutants; D019216:Metals, Heavy