MPD basics

The bridge between biology and manufacturing

Microbial process development is an activity within bioprocess engineering. Microbial process development results in a Bioprocess that, in turn, results in a Bioproduct.

Terminology surrounding microbial process development.

Components in microbial process development

Microbial process development is a complex activity that consists of several components. Below, we give a brief (and incomplete) overview.

Strain development

Selection or engineering of a microbial host. E.g., E. coli, Saccharomyces cerevisiae, etc. This includes genetic modifications such as:

• Pathway insertion or optimization

• Knockouts to reduce byproducts

• Promoter tuning for expression control

Media and growth optimization

Designing nutrient composition. E.g., carbon, nitrogen, trace elements.

Controlling process parameters. E.g., pH, temperature, oxygen transfer.

Feeding strategy

Batch, fed-batch, or continuous cultivation strategies. Feeding profiles. E.g., glucose-limited feeding to avoid overflow metabolism.

Bioreactor configuration and mixing.

Scaling

Scale from lab to pilot to production facilities. In practice, to transition from shake flasks to bench-top bioreactors to industrial fermenters.

While scaling, you must address several new challenges. E.g., oxygen transfer limitations, shear stress, heat removal.

Monitoring

Understand what's going during the bioprocess.

• OD (optical density)

• pH

• DO (dissolved oxygen)

• Metabolites

• Plate counts (CFU)

• BactoBox® (cells/mL)

• etc.

Downstream considerations

This is a huge topic on its own. The basics are:

• Bioproduct isolation (recovery)

• Bioproduct concentration, purification, dehydration, etc.