Electronic Nose‐Based Methanol Feedback Precision Control Strategy for High‐Yield Alkaline Phosphatase Fermentation by Hansenula polymorpha

Alkaline phosphatase (ALP), an important industrial enzyme, has a wide range of applications in animal food, biotechnology, and environment. Methanol, as a key inducer in the fermentation process of Hansenula polymorpha , significantly affects ALP expression. This study was intended to optimize the methanol concentration during alkaline phosphatase fermentation, develop a methanol detection model based on electronic nose responses, and apply a feedback control strategy for online monitoring of methanol concentration in alkaline phosphatase fermentation. The results showed that the online detection and concentration feedback control strategy based on the electronic nose was more effective in maintaining the methanol concentration within limited and different methanol control concentrations, which had significant effects on Hansenula polymorpha metabolism. The maximum intracellular and extracellular ALP activities reached 2604.19 U/mL and 415.46 U/mL at 5 g/L. At this concentration, the extracellular ALP activities were 1.27 and 2.71 times higher than those at 1 and 10 g/L, respectively, while the intracellular ALP activities were 2.96 and 3.03 times higher than those at 1 and 10 g/L, respectively. In summary, this study not only provides a scientific method for the feedback control and optimization of methanol concentration during efficient ALP fermentation but also provides a new technological path for the efficient production of industrial enzymes.