Textbook definition: Upstream processing refers to the stage of bioprocessing where cells are grown to the desired quantity in bioreactors, and all stages related to this such as cell isolation, cell cultivation, media preparation, cell banking & storage to culture expansion until harvest.
Basically, upstream processing is everything related to mass-production of the cells and product.
- Innoculation: Introduction of the cells to media to initiate cell expansion.
- Cell expansion: Increasing the amount of cells by scaling up the process.
Upstream processing is important as in order to make a scientific breakthrough into a product on the market it must be able to made in large quantities at a low cost.
As cells are living organisms, designing an upstream process is complex and many factors must be taken into account, i.e. oxygen dispersion, shear sensitivity of the cells, nutrient concentrations, etc. We will go through all of these factors in later posts. Due to the cells complex nature it is usually necessary to start the process at a small-scale and then increase the size of the vessel in increments.
Ensuring the cells produce the desired amount of product is also a part of upstream processing, but we will put the genetic engineering sections in our “Everything you need to know about cells” category as it seems more relevant to cells, and instead focus on optimising upstream conditions to maximise product synthesis.
Bioprocessing Explained 