ABSTRACT
A mixed culture of moderately thermophiles showed good performance in bioleaching of chalcopyrite. Its community structure was investigated by amplified ribosomal DNA restriction analysis. The result shows that Leptospirillum ferriphilum and Acidithiobacillus caldus were the predominant bacteria and Ferroplasma thermophilum, the only archaea, could be always detected during bioleaching. Therefore, real-time PCR assay was performed to monitor these microorganisms' dynamics in the solution and on the mineral surface. It is shown that both in the solution and on the mineral surface, A. caldus was the dominant species at the early stage and L. ferriphilum was the predominant species at the later stage. The amount of the same species exhibited different variation trends in the solution and on the mineral surface. The amount of attached L. ferriphilum increased faster than that of the free one, and the amount of attached F. thermophilum kept at a stable level while the free one increased rapidly at the end.
Subject(s)
Archaea/isolation & purification , Archaea/metabolism , Bioreactors/microbiology , Copper/metabolism , Archaea/classification , Biodegradation, EnvironmentalABSTRACT
The foam behavior of three polypropylene glycols covering the molecular weight range between 192 and 725 g/mol has been examined. Static and dynamic surface tension data, as well as bubble size distribution and retention time in the foam, were incorporated into a simple model of foam stability. The latter clearly indicates that surface tension differences between the plateau border and lamellar region adjacent to the bubble surface are the dominant factor in controlling foamability, causing liquid flow in the direction opposite to liquid drainage, a process termed the Marangoni effect.
