Introduction
Penicillium chrysogenum is one of the most numerous eukaryotes
on earth with conidia present in concentrations up to
350 m3 air and 15000 g1 household dust (Beguin & Nolard
1994; Scott 2001). Even sampling from the upper-atmosphere
and the Antarctic has detected this ubiquitous fungus (Pitt
2000), and as experienced by Alexander Fleming (Fleming
1929), avoiding P. chrysogenum as a contaminant is near
impossible. Apart from readily acting as a food spoilage agent
(Samson et al. 2010), this fungus may have remained unremarked
by the scientific community if it were not for its
antibacterial producing properties.
In Sep. 1928, Fleming witnessed the contamination of one
of his Staphylococcus plates by Penicillium rubrum and observed
a halo of inhibition on his bacterial colonies (Fleming 1929).
The antibiotic effect from this mould was via the production of
the secondary metabolite penicillin, which was later refined
for production by Ernst Chain and Howard Florey (Henk et al.
2011). These three scientists were acknowledged for their
discovery by joint award of the Nobel Prize for Physiology or
Medicine in 1945.
The taxonomy and true identity of Fleming’s fungus was
initially and has remained persistently controversial. The
original penicillin-producing fungus was first described as
Penicillium rubum by the experienced mycologist Charles La
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