Phenotyping the quality of complex medium components by simple online-monitored shake flask experiments

Area of Science:

• Biotechnology
• Microbial Cultivation
• Process Analytical Technology (PAT)

Background:

• Complex media, including yeast extracts, are vital for microbial cultivation but exhibit lot-to-lot variability.
• This variability impacts microbial growth, product yield, and quality in biopharmaceutical production.
• Assessing raw material quality is a key aspect of the FDA's Process Analytical Technology (PAT) initiative.

Purpose of the Study:

• To evaluate the impact of different yeast extracts and auto-induction medium lots on the metabolic activity and product yield of recombinant Escherichia coli.
• To assess the utility of the Respiration Activity Monitoring System (RAMOS) for screening raw material lots.

Main Methods:

• Utilized the Respiration Activity Monitoring System (RAMOS) for online monitoring of microbial respiration.
• Cultivated four recombinant Escherichia coli variants under induced and non-induced conditions using various yeast extract and auto-induction medium lots.
• Performed offline analysis to determine volumetric activity and product yield.

Main Results:

• Lot variations in yeast extracts and auto-induction media caused significant differences in oxygen transfer rate (OTR) and volumetric activity under induced conditions.
• These variations were independent of the specific recombinant Escherichia coli variant.
• Online monitoring enabled the detection of critical cultivation phases, such as glycerol depletion, for reproducible offline analysis.

Conclusions:

• Cultivations in complex media are susceptible to variations in product quality and quantity due to raw material inconsistencies.
• The RAMOS technique provides a reliable method for screening and phenotyping complex raw material lots by measuring respiration activity.
• Efficient assessment of raw material lots is achievable by visualizing their distinct effects on culture behavior and product outcomes.