Class: BE210
Group: R1
Members:
FACILITATOR Juan Carlos Baez
TIME & TASK KEEPER Nicola Francis
SCRIBE Emily Hsu
PRESENTER Natasha Sardesai
Date: May, 2002
Abstract:
The effect of pH on the growth constants of anaerobically grown baker’s
yeast was determined using the PENNCELL reactor system, at a temperature
of 37.0 ± 0.1oC and using pH values of 4, 5, 6, and 7. The effect
of pH on anaerobic growth constants was subsequently compared to the growth
constants of aerobically grown yeast. A 5-minute nitrogen treatment at
0.5 L/min N2 kept the oxygen concentration at a level suitable for anaerobic
respiration (3 ppm). A negative correlation between growth constant and
pH was found, with growth constants ranging from 2.7x10-3 ± 2x10-4
at pH 7 to 3.5x10-3 ± 1x10-4 at pH 4. There was no statistical difference
between the growth constants at pH 5 and pH 6. The comparisons of individual
growth constants of anaerobic and aerobic yeast growth were inconclusive.
However, anaerobic yeast grew an average of 1.2 times faster than the aerobic
yeast.