While most of the batch culture propagations were conducted using wort as the growth substrate, I also looked at how batch culture growth proceeded using MYPG as the growth substrate. This study was performed with each of the three Brettanomyces strains from Wyeast by inoculating them into 100 ml of MYPG substrate and 100 ml of wort substrate. The substrates were inoculated by looping cells from a single colony grown on MYPG agar. Initial cell growth in both mediums proceeded for 7 days before the propagations were poured aseptically into 500 ml of wort in order to observe any difference the starting medium had over subsequent growth. The second propagation step underwent a further 7 days of cell growth with comparisons made regarding overall cell growth.
Growth curve of three Wyeast strains initially sub-cultured in MYPG substrate
as compared to the same strains initially cultured separately in wort substrate.
Both substrates were further inoculated into 500ml of wort substrate and
grown for 168 hours (7 days) at 28°C with 80-rpm agitation.
Growth curve comparison between the collective means of three Wyeast strains
initially sub-cultured in MYPG substrate as compared to the same strains
initially cultured separately in wort substrate. Both substrates were further
inoculated into 500ml of wort substrate and grown for 168 hours (7 days)
to observe initial impact on cell growth. Mean cell count data was obtained
from all three Wyeast strains grown at 28°C with 80-rpm agitation.
I had previously not had growth this rapid before yielding high cell counts. It would appear that MYPG is a better suited substrate for initial culturing of cells and when looking to propagate up cells for pitching into fermentation. More information on Propagation and Batch Culture Growth can be found by following the link.