Mid-Infrared Spectroscopy and Multivariate Analysis to Characterize Lactobacillus acidophilus Fermentation Processes

Area of Science:

• Biotechnology
• Analytical Chemistry
• Process Engineering

Background:

• Global biotech competition necessitates consistent production and optimization strategies.
• Process Analytical Technology (PAT) and mid-infrared (MIR) spectroscopy offer real-time monitoring of cellular physiology via substrate and by-product concentrations.
• Multivariate statistics combined with MIR spectroscopy can be used for production performance mapping.

Purpose of the Study:

• To characterize Lactobacillus acidophilus fermentations using at-line spectroscopy, chemometric modeling, and post-process fitting.
• To evaluate alternative data arrangements and chemometric methods including Principal Component Analysis (PCA), Multivariate Curve Resolution (MCR), and Parallel Factor Analysis (PARAFAC).
• To extract key parameters (rate constant, time of inflection) for process performance description and batch-to-batch variation analysis.

Main Methods:

• At-line mid-infrared (MIR) spectroscopy was employed for data acquisition.
• Chemometric methods including Principal Component Analysis (PCA), Multivariate Curve Resolution (MCR) (augmented and individual-run), and Parallel Factor Analysis (PARAFAC) were applied.
• Post-process fitting was used to extract kinetic parameters from the chemometric models.

Main Results:

• Unconstrained PCA primarily modeled biomass changes.
• Constrained models (PARAFAC and MCR) successfully modeled substrate decrease and lactic acid increase over time.
• MCR applied to individual batch data, followed by post-process fitting, proved effective for MIR spectroscopic monitoring.

Conclusions:

• Key parameters like rate constant and time of inflection can describe fermentation dynamics and batch variations.
• Multivariate curve resolution (MCR) on individual batch data is the preferred strategy for MIR spectroscopic monitoring in this context.
• This approach enhances production consistency and optimization in the biotech industry.