Two-dimensional fluorescence spectroscopy: a novel approach for controlling fed-batch cultivations

Area of Science:

• Biotechnology and biochemical engineering
• Industrial microbiology
• Process analytical technology (PAT)

Background:

• Industrial fed-batch cultivations require precise control of substrate concentrations to maximize biomass yield.
• Controlling substrate levels is crucial to prevent the formation of overflow metabolites like ethanol.
• Current monitoring methods may not offer the speed and accuracy needed for real-time process adjustments.

Purpose of the Study:

• To develop a novel on-line monitoring and fed-batch control strategy for industrial cultivations.
• To utilize fluorescence measurements and multivariate data analysis for rapid detection of metabolic states.
• To optimize biomass yield by preventing overflow metabolism in Saccharomyces cerevisiae cultivations.

Main Methods:

• Development of a robust instrumentation system for in situ fluorescence measurements.
• Establishment of a chemometric model using multivariate data analysis for real-time metabolic state prediction.
• Integration of the model with a feedback control system to adjust glucose feed rate dynamically.

Main Results:

• The developed method accurately detected ethanol production in real-time during aerobic Saccharomyces cerevisiae fed-batch cultivations.
• By predicting the metabolic state from fluorescence intensities, the glucose feed rate was effectively controlled.
• Ethanol production was completely avoided, leading to a significant increase in biomass yield.

Conclusions:

• The novel fluorescence-based method provides a robust and efficient solution for on-line monitoring and fed-batch control.
• This approach is suitable for industrial applications, enabling enhanced biomass yield and process optimization.
• Real-time metabolic state prediction via fluorescence offers a powerful tool for controlling microbial fermentations.