Heavy metal ion influence on the photosynthetic growth of Rhodobacter sphaeroides

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• 作者：Livia Giotta ; Angela Agostiano ; Francesca Italiano ; Francesco Milano and Massimo Trotta
• 关键词：Purple bacteria ; Heavy metal toxicity ; Phototrophic growth ; Concentration– ; effect curves ; EC₅₀ ; Heavy metal ion effects on cellular pigments ; Bioremediation
• 刊名：Chemosphere
• 出版年：2006
• 出版时间：March 2006
• 年：2006
• 卷：62
• 期：9
• 页码：1490-1499
• 全文大小：315 K

文摘

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⁺, , and 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 . 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.