Isolation and identification of a copper-removal Rhodopseudomonas strain

Abstract:

[Background] The treatment of heavy metal pollution is imminent because heavy metal poses a major threat to the environment and human health. Biological treatment methods are preferred because of the advantages of low cost, good treatment effect and no secondary pollution. [Objective] From the 13 m deep water body of the Liaohe estuary, a strain possessing strong pigment-producing ability and high- concentration Cu2+ removal ability was screened by the purple non-sulfur bacteria enrichment medium. [Methods] Morphological, physiological and biochemical characteristics and molecular biological methods were used to identify the strain. The content of Cu2+ was determined by spectrophotometry with sodium diethyldithiocarbamate. [Results] The strain was identified as Rhodopseudomonas and named as Rhodopseudomonas sp. gh32. The optimal growth temperature and growth pH of strain gh32 were 30 °C and 7.0, respectively. The strain gh32 grew normally in the range of pH 5.0?10.0. The strain gh32 could grow normally in 3 mmol/L CuSO4 solution. The strain gh32 could utilize hydrogen sulfide and monosaccharides, such as glucose and mannose. The removal rate of Cu2+ was over 99% in strain gh32 within 24 h. The ability to treat Cu2+ was 1 331 g/g dry bacterial weight or 167.6 g/g wet bacterial weight. [Conclusion] The strain gh32 was highly resistant to Cu2+ and there was a high removal rate of Cu2+ by strain gh32. It will be a potential strain of treatment wastewater containing Cu2+. This study provided support for biological treatment of heavy metal wastewater.