In both Figs. 3 and 4, we also observed that after inoculation
the cells grew at successively increasing rates, and they eventually
grew at 0.56 h
−1
, the μ
. Besides, the time needed to
reach μ
max
max
increased with increasing agitator speed. In other
words, the cells needed a longer time to adapt themselves to
an environment of higher shear force; nevertheless, neither the
extent of cell growth nor the HA yield changed with changing
shear force. Similar results were also obtained under anaerobic
conditions, as shown in Fig. 5a. Furthermore, in Fig. 5b it shows
that, during growing at μ
, the cells still needed an adaptation
time to recover their growth rate as the agitator speed was shifted
to a higher speed, say, from 200 to 400 rpm.