A quantitative assay of mixed cultures of bacteria
and the fungus Aspergillus flavus was carried out. The
assay was based on the estimation of glucosamine formed
by the hydrolysis of chitin.
The bacteria used were typical Gram-positive and
Gram-negative bacteria commonly found in spoiled food.
They included, Escherichia coli, Bacillus cereus, Staphylo
coccus aureus and Pseudomonas aeruginosa.
The experiments carried out involved mixing
cultures of bacteria and fungi immediately prior to
estimation or alternatively fungal and bacterial cultures
were mixed, grown for 40 hours and then estimated for
Results obtained show, that when cultures are mixed
immediately prior to estimation, there is no significant
effect on glucosamine levels. When Gram-negative bacteria
are grown with A.flavus prior to estimation there is no
significant effect on glucosamine levels compared with
pure cultures of A.flavus. However, when Gram-positive
bacteria are mixed with fungi grown for 40 hours and
glucosamine is estimated, there is a significant reduction
in the level of glucosamine formed. It was shown that
this is due to bacterial growth competing with the fungi
and causing a considerable reduction in the amount of
fungal mycelium formed.
A Masters Thesis. Submitted in partial fulfilment of the requirements for the award of Master of Philosophy of Loughborough University.