Difference between revisions of "Industrial fermentation"

<onlyinclude>'''Industrial fermentation''' is a biotechnological process which uses microorganisms (genetically modified or not),  in particular bacteria, yeasts, fungi or algae, to make useful products. The cells are real "cell factories" for the industrial conversion of renewable feedstocks to bulk chemicals, fine chemicals, platform chemicals, pharmaceutical ingredients, bio-fuels, bio-plastics ... It is a multidisciplinary technology and includes the integrated application of disciplines such as biochemistry, microbiology, molecular genetics and process technology to develop useful processes and products.</onlyinclude>

Oils and fats are present in [[food waste]] such as gravy, used cooking oil and grease. The can directly be used as fermentation substrate. As they are not water soluble, extensive mixing is required to allow a good contact between the liquid droplets and the fermentation water phase.

Microorganisms used in industrial fermentations include: bacteria, yeast and mold. In practice, these are well-known, productive and harmless (GRAS - Generally Regarded As Safe) production organisms, equipped with the new genetic information, that are used to produce the desired products in high yield and efficiency.  A major advantage is that these often genetically modified microorganisms do their work under controlled conditions in a fermenter or bio-reactor, carefully contained and separated from the outside world (contained environment). They cannot escape from the factory so that ecological problems or concerns regarding the release of genetically modified organisms in the environment are avoided.

* a cleaning and sterilization system: to avoid contamination with other, undesired microorganisms

As it involves living organisms, a fermentation process is typically conducted under mild conditions (pH and temperature). As a result, the energy consumption is relatively low as well as the capital and operating costs. However, fermentation technoloiges are complex and sensitive requiring careful control of quality and safety of the raw materials, process parameters, contamination, etc.  

=== Bio-products ===

 

* Monosodium glutamate (MSG)

 

*Lactic acid  

* Citric acid  

The first step in the post-treatment of fermentation broths cultures, also known as '''downstream processing (DSP)''',  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.