3.4.1 Reducing the adaptation time to methanol induction
environments
When the second methanol induction phase was initiated by feeding
methanol, MutS P. pastoris cells has to take a
long-term time to adapt the environment of methanol induction by
synthesizing alcohol oxidase (AOX) to drive methanol metabolism. In
general, the stoppage of this adaptation phase could be easily and
indirectly reflected by the drop of DO and the increased OUR (online
data). As shown in Fig.4, when using the periodic DO control strategy
(strategy C), the drop of DO and the increased OUR occurred at about 3 h
during the methanol induction phase, which was only one half of that
obtained with the “high DO-low glycerol concentration” control
strategy (strategy A) when using same methanol induction strategy. As
the batch using “low DO-high glycerol concentration” control strategy
(strategy B), the drop of DO and the increased OUR were not observed
throughout the entire methanol induction phase (data not shown), leading
to the failure of hLYZ production.