Optimizing recombinant protein expression via automated induction profiling in microtiter plates at different...

Area of Science:

• Biotechnology
• Microbial Physiology
• Protein Expression

Background:

• Escherichia coli (E. coli) is a primary host for recombinant protein production.
• Production efficiency is influenced by numerous parameters, necessitating high-throughput investigations.
• Optimizing induction conditions is crucial for maximizing protein yield.

Purpose of the Study:

• To extensively examine the effects of temperature, induction time, and inducer concentration on E. coli metabolic state and recombinant protein production.
• To determine optimal induction parameters for E. coli Tuner(DE3) pRhotHi-2-EcFbFP using high-throughput screening.
• To assess the utility of online monitoring systems (BioLector and RAMOS) for induction profiling.

Main Methods:

• High-throughput induction profiling of E. coli Tuner(DE3) pRhotHi-2-EcFbFP in 48-well Flowerplates and 96-well plates using a robotic platform.
• Parallel shake flask cultivations with online monitoring of respiration activity using BioLector and RAMOS devices.
• Systematic variation of temperature (28, 30, 34, 37 °C), induction time, and isopropyl-beta-D-thiogalactopyranoside (IPTG) concentration.

Main Results:

• Optimal induction conditions varied significantly with temperature.
• The most effective inducer (IPTG) concentrations were found to be 0.05–0.1 mM, 10-20 times lower than standard recommendations.
• Higher cultivation temperatures led to increased metabolic burden, necessitating lower IPTG concentrations for optimal results.
• Induction time was less critical when optimal IPTG concentrations were employed.
• Similar outcomes were observed in both microtiter plates and standard 96-well plates.

Conclusions:

• Online monitoring systems and robotic platforms effectively minimized experimental effort for optimizing E. coli induction.
• Detailed induction analysis is essential for maximizing product formation.
• Cultivation temperature directly impacts optimal induction conditions, requiring adaptation of IPTG concentration.
• A key finding is that higher cultivation temperatures necessitate lower inducer concentrations for optimal protein production in E. coli.