3.3. Screening for the optimal ratio between Dekkera bruxellensis
KN89 and G. intermedius KN89 for glucuronic acid production
The original ratio between yeast and AAB in kombucha brewing
is vital for its metabolites production. Since both strains can
consume sucrose in the medium, the increasing of one's initial
population size may rapidly colonize the niches, dominate the
other strain and cause the influences on the composition of the
final metabolites compounds as the consequence of microbial
competition (Hibbing, Fuqua, Parsek, & Peterson, 2010). Thus,
screening of different initial amount of living cell between these
two components is essential, particularly, in reformation of the
symbiosis for specific fermentative purpose. Fig. 2a demonstrates
the concentration of glucuronic acid produced by different combination ratios between D. bruxellensis KN89 and G. intermedius
KN89. The unfermented sample (only tea broth) showed only
1.06e ± 0.8 mg L1 glucuronic acid while the combination 4Y6A
gave the highest one of 102.56a ± 3.55 mg L1
. The traditional culture and the 3Y7A symbiosis produced the similar level of glucuronic acid (30.3d ± 2.3 and 28.7d ± 1.45 mg L1
). Other ratios of
symbiosis presented the moderated levels within a range from
32.3c ± 3.5e44.76b ± 1.75 mg L1 (Fig. 2a).