Monitoring And Modeling Of Microbial Fermentation Based On Near Infrared Spectroscopy

Fermentation engineering is finding wider and wider application in all fields.The research of fermentation process control and optimization is attracting increasing interest from researchers.Real-time online monitoring of the key parameters of fermentation process is the important premise to realize the fermentation process control and optimization.Currently,only a few parameters,such as temperature and pH,could be on-line monitored in fermentation process.The key parameters of fermentation,such as biomass and substrate concentration,were analyzed mainly by off-line methods.This situation seriously restricted the improvement of fermentation process control and optimization.Near infrared spectroscopy technology has great potential in on-line monitoring of important parameters in fermentation process,because of its advantages such as high analysis speed,various measurement methods and no need of sample pretreatment.To overcome the deficiencies of time-consuming,laborious and manual errors from offline measure method,this study applied near infrared spectroscopy to online monitor the key parameters of two fermentation processes.To realize on-line monitoring of 1,3-propanediol fermentation process,this paper studied the spectra of the one-component solutions of glycerol and 1,3-propanediol and established the quantitative model.According to the characteristics of the fermentation process,this paper designed and set up the fermentation process on-line monitoring experimental platform based on the near infrared spectra technology and finished the fermentation experiments.By pre-processing the real-time sampled spectra,a partial least-squares algorithm was applied to establish and optimize on-line monitoring models for the biomass change and the glycerol concentration during a 1,3-propanediol fermentation process.Through experimental verification,the root mean square error of these two models are 0.3416(OD)and 2.3334g/L,respectively.It proved that the established models can be used to real-time on-line minitor the biomass change and substrate glycerol concentration during a 1,3-propanediol fermentation process.For ethanol fermentation process,this paper used near infrared spectroscopy to analyze the substrate glucose solution and the main product ethanol solution and established the quantitative model.Based on the characteristics of the metabolism of ethanol fermentation process,a fermentation process online monitoring experimental platform was designed with near infrared spectroscopy instrument.Near infrared spectra of ethanol fermentation process were measured by this experiment platform.On the basis of the study of using near infrared to monitor the key parameters of 1,3-propanediol fermentation process,this paper analyzed the near infrared spectra and used the partial least squares algorithm to establish the on-line monitoring models of biomass change,ethanol concentration and glucose concentration of ethanol fermentation process.A new ethanol fermentation experiment was used as the external validation experiment.The root mean square error of the models were 0.2343(OD),1.7131 g/L and 2.7197 g/L,respectively.These experimental results showed that the established models could be effectively used for key parameters on-line monitoring during a ethanol fermentation process.