Enzyme-Linked Immunofiltration Assay To Estimate Attachment of Thiobacilli to Pyrite

Abstract

An enzyme-linked immunofiltration assay (ELIFA) has been developed in order to estimate directly and specifically Thiobacillus ferrooxidans attachment on sulfide minerals. This method derives from the enzyme-linked immunosorbent assay but is performed on filtration membranes which allow the retention of mineral particles for a subsequent immunoenzymatic reaction in microtiter plates. The polyclonal antiserum used in this study was raised againstT. ferrooxidans DSM 583 and recognized cell surface antigens present on bacteria belonging to the genusThiobacillus. This antiserum and the ELIFA allowed the direct quantification of attached bacteria with high sensitivity (104 bacteria were detected per well of the microtiter plate). The mean value of bacterial attachment has been estimated to be about 105 bacteria mg−1 of pyrite at a particle size of 56 to 65 μm. The geometric coverage ratio of pyrite by T. ferrooxidans ranged from 0.25 to 2.25%. This suggests an attachment of T. ferrooxidans on the pyrite surface to well-defined limited sites with specific electrochemical or surface properties. ELIFA was shown to be compatible with the measurement of variable levels of adhesion. Therefore, this method may be used to establish adhesion isotherms of T. ferrooxidans on various sulfide minerals exhibiting different physicochemical properties in order to understand the mechanisms of bacterial interaction with mineral surfaces.

Electrochemical growth of Acidithiobacillus ferrooxidans on a graphite electrode for obtaining a biocathode for direct electrocatalytic reduction of oxygen

“…It has been shown that the EPS excreted by At. ferrooxidans cells attached to pyrite contain exopolymer-complexed Fe 3+ ions that allow electron transfer between the cells and the mineral (Dziurla et al, 1998;Gehrke et al, 1998). In the present work, At.…”

Characteristics of attachment and growth of Thiobacillus caldus on sulphide minerals: a chemotactic response to sulphur minerals?

“…Attachment has also been found to occur in a non-random fashion (Edwards et al, 1998). Hence, many studies have focused on the quantification of cell attachment densities (Southam and Beveridge, 1992;Dziurla et al, 1998;Edwards et al, 1998) and the characterization of attachment (Chakrabarti and Banerjee, 1991;Ohmura et al, 1993;Lawrence et al, 1997;Edwards et al, 1998). Fewer studies have attempted to quantify microbial growth on surfaces over time, and little is known about the nature of site specificity for attachment.…”

Process Oriented Characterization in Bioleaching Co-Cu Minerals

“…When polymetallic sulphides are subjected to bioleaching, the microorganisms could be found either in the liquid phase (refereed as planktonic MO) or attached to the surface (what we called fixed or anchored to the surface MO), the latter ones forming the biofilm. Their importance in view revealing the responsible leaching mechanisms have stimulated numerous studies for counting, characterizing and identification, e.g., Q-PCR, MPN (Beach and Sunner, 2004;Kinzler et al, 2003;Dziurla, 1995Dziurla, , 1998. The ultimate aim has been to design the optimum proportion of microorganism members that a used consortium for bioleaching should contain.…”

“…For the latter, we have chosen a methodology based on physicochemical desorption, which is known by its simplicity and accuracy and at the same time is able to distinguish the two types of anchored bacteria: transiently-bound (reversibly detachable) and strongly-bound. The method was originally developed by Monroy et al (1993) and used by Dziurla (1995Dziurla ( , 1998. In our case, the estimation of the transiently bound (reversibly detachable) microorganisms has been realized by gentle wash-out using 9K solution, while the strongly-adhered ones-by means of a "Tween 80" detergent which is a combination between anionic and non-ionic surfactants.…”