In situ investigation and visualisation of microbial attachment andcolonisation in a heap bioleach environment: the novel biofilm reactor

摘要

In this paper, the development of a novel means of investigating the attachment and subsequent biofilm formation of mineral bioleaching microorganisms to mineral surfaces in situ is described. The protocol was developed to investigate the interactions of microorganisms with sulphide minerals and low grade chalcopyrite ore under conditions resemblant of a bioheap environment. The method makes use of a biofilm reactor in which thin sections of mineral ore are mounted. The reactor is operated as a continuous flow-through system. Attachment of pure and mixed cultures of A. ferrooxidans and L. ferriphilum is assessed. The technique allows for the investigation of microbial ecology with special regard to microbe-mineral attachment, site and mineral specific associations of microorganisms and spatial organisation of microbial communities present through the use of fluorescent microscopy techniques. Preliminary fluorescent in situ hybridisation (FISH) analysis of the attachment of Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans to massive chalcopyrite sections, as well as to low grade chalcopyrite containing ore sections are presented.