Difference between revisions of "Industrial fermentation"

=== Scale-up of industrial fermentations ===

=== Scale-up of industrial fermentations ===

Typically, a pure starter culture (or seed), maintained under carefully controlled conditions, is used to inoculate sterile petri dishes or liquid medium in the shake flasks. After sufficient growth, the preculture is used to inoculate the seed fermenter. Because industrial fermentations tend to be large (typically 1–250 m³), the inoculum is built up through several successively larger stages, to 5–10% of the working volume of the production fermenter. However, scale-up of a fermentation process is not straightforward as an increase in fermenter size affects the various process parameters in different ways. Therefore, ample expertise is required to find a compromise between all process parameters.

Typically, a pure starter culture (or seed), maintained under carefully controlled conditions, is used to inoculate sterile petri dishes or liquid medium in the shake flasks. After sufficient growth, the preculture is used to inoculate the seed fermenter. Because industrial fermentations tend to be large (typically 1–250 m³), the inoculum is built up through several successively larger stages, to 5–10% of the working volume of the production fermenter. However, scale-up of a fermentation process is not straightforward as an increase in fermenter size affects the various process parameters in different ways. Therefore, ample expertise is required to find a compromise between all process parameters.

Depending on the type of microorganisms and its genetic modifications, a range of products can be synthesized. The most common products are listed and divided over two categories: (1) biomass, (2) bioproducts. In case of the latter, some products require complex genetic modifications.

Depending on the type of microorganisms and its genetic modifications, a range of products can be synthesized. The most common products are listed and divided over two categories: (1) biomass, (2) bioproducts. In case of the latter, some products require complex genetic modifications.

* Phenylalanine

* Phenylalanine

The first step in the post-treatment of fermentation broth cultures, also known as '''downstream processing (DSP)''',  is to remove the cells from the medium.  This is typically performed by a solid-liquid separation technology, such, as [[centrifugation]] or [[membrane filtration]]. Each fraction can then undergo further processing, depending on whether the product is the biomass itself or an intra- or extracellular product. While intracellular products require cell disruption to release the products, extracellular products are solubilized in the depleted fermentation medium. Cell disruption techniques can be divided into mechanical methods (f.e. [[homogenisation]], [[Sizing|grinding]], [[Ultrasonication|sonication]], [[microwave treatment]], [[steam explosion]]) and non-mechanical methods (f.e. osmotic or temperature shock, [[Enzymatic processes|enzymatic destruction]]).  To further purify and concentrate the products several methods can be used including [[chromatography]], [[solvent extraction]], [[Crystallisation and precipitation|crystallization]], [[distillation]], [[drying]] etc. The choice of purification technology is depending on the characteristics of the desired products.

The first step in the post-treatment of fermentation broth cultures, also known as '''downstream processing (DSP)''',  is to remove the cells from the medium.  This is typically performed by a solid-liquid separation technology, such, as [[centrifugation]] or [[membrane filtration]]. Each fraction can then undergo further processing, depending on whether the product is the biomass itself or an intra- or extracellular product. While intracellular products require cell disruption to release the products, extracellular products are solubilized in the depleted fermentation medium. Cell disruption techniques can be divided into mechanical methods (f.e. [[homogenisation]], [[Sizing|grinding]], [[Ultrasonication|sonication]], [[microwave treatment]], [[steam explosion]]) and non-mechanical methods (f.e. osmotic or temperature shock, [[Enzymatic processes|enzymatic destruction]]).  To further purify and concentrate the products several methods can be used including [[chromatography]], [[solvent extraction]], [[Crystallisation and precipitation|crystallization]], [[distillation]], [[drying]] etc. The choice of purification technology is depending on the characteristics of the desired products.