The development of preservation methodology can be a
difficult process, as there are a plethora of variables that can affect
preservation success including (but not limited to) ensuring that
all species are equally preserved and represented in a revived culture
and that there is no selective preservation of species due to
the preservation method or the medium used for revival of cells
(Benson, 2008; Hubálek, 2003). In this study, three existing methods
were investigated for their applicability for preserving mixed
salt-tolerant bioleaching microorganisms. These included cryopreservation
at 80 C (Pegg, 2007; Fuller, 2004), liquid-drying
(Malik, 1998, 1990; Sakane et al., 1992), and cold storage at 4 C.
The viability of revived cultures was determined by total cell
counts and bioleaching activity tests, and the results were compared
to the viability of maintained live cultures as the standard
method of culture maintenance currently used in many
laboratories.