Adsorption of Bacillus subtilis to minerals: effect on the notation of dolomite and apatite

Many strains of bacteria are able to adsorb Ca(II) and Mg(II) ions from aqu eous solution and, in some cases, the adsorption can be very specific. For example, Bacillus subtilis typically binds Mg(II) much more readily than Ca (II). Bacteria can also adhere to the surfaces of minerals containing calci um and magnesium, either enhancing or depressing the notation of these mine rals. Since B. subtilis binds Mg(II) preferentially, it was reasoned that a dhesion to a mineral containing magnesium and calcium (dolomite) might be q uite different from adhesion to a mineral containing only calcium (apatite) and this difference could possibly be utilized in minerals processing. Exp eriments investigating the binding of Ca(II) and Mg(II) to B. subtilis cell s were initiated and anionic collector microflotation of pure dolomite and apatite mineral samples in the presence and absence of these bacteria was p erformed. Since Ca(II) and Mg(II) also bind to dolomite and apatite, zeta p otential measurements as a function of pH in the presence and absence of th ese ions were performed in order to better elucidate the effect this bindin g may have on the attachment of B. subtilis to the two minerals.