Figure 9: Chitinase activity after long incubations in YPD. Chitinase was measured with 4-nitrophenyl-N-N′-diacetyl- -D-chitobioside and 4-nitrophenyl -D-N-N′-N′′-triacetylchitotriose as substrates. Samples were taken from experiments similar to those for the growth curves with different concentration of chitosan, at three different times of growth, as indicated. Activity was measured in aliquots of the supernatants as described under experimental procedures.