I work with Tween 80 to recover microorgasnisms from decayed stone.
There is an interesting paper (Lewis et al) about the use of Tween
and related products. They conclude that low concentrations of Tween
(about 0.001%) are more effective at recovering bacteria and a
greater diversity of colony types can be isolated.
I have carry out a similar study, concluding that low
concentrations (0.0005%) are most suitable for recovering bacteria.
I think that high concentrations of Tween 80 are toxic for some
microorganisms. I have measured the toxicity of Tween 80 to bacteria
by means of Microtox assay with Photobacterium phosphoreum. 0.05% of
Tween 80 reduce to 0% the ligth emission of this strain. I know that
it is imposible to extrapolate the results obtained with a single
strain to a complex population, but if Tween 80 is toxic at this
level to P. phosporeum, why not to other microorganisms?.
Lewis, May and Bravery. Isolation and enumeration of autotrophic and
heterotrophic bacteria from decayed stone. In: Proceedings of the 5th
International Congress on Deterioration and Conservation of Stone.
Vol 2, LAussanne 1985.