"He makes grass grow for the cattle, and plants bringing forth food from - cultivate for people to the earth: wine that gladdens human hearts, oil to make their faces shine, and bread that sustains their hearts."
Matthew Arnold
Join us to experience the innovation and science of the fermentation association in Israel – where every culture comes together to create something extraordinary!"
What is Fermentation?
Microorganisms fermentation
Microorganisms fermentation is a metabolic process that occurs in microorganisms, such as bacteria,
yeast, and fungi, wherein organic compounds are converted into simpler substances under anaerobic
(without oxygen) or aerobic (with oxygen) conditions. This process typically involves the breakdown of
carbohydrates, such as sugars or starches, into products like alcohol, acids, or gases, accompanied by
the release of energy.
In anaerobic fermentation, microorganisms convert sugars or other organic compounds into energy
and metabolic byproducts without the presence of oxygen. Common anaerobic fermentation products
include ethanol (alcohol), lactic acid, and acetic acid. This process is widely used in the production of
alcoholic beverages, dairy products like yogurt and cheese, and various industrial chemicals.
In aerobic fermentation, microorganisms utilize oxygen to metabolize organic compounds, producing
energy and byproducts such as carbon dioxide and water. This process is essential for the growth and
metabolism of aerobic microorganisms and is utilized in various industrial processes, including the
production of organic acids, enzymes, and pharmaceuticals.
Plant cell fermentation
Plant cell fermentation or plant cell culture fermentation, refers to the process of utilizing plant cells or
tissues to produce desired products through metabolic pathways like microbial fermentation. While
fermentation in plant cells shares some similarities with microbial fermentation, there are key
differences due to the complex nature of plant metabolism and cell biology. Plant cell fermentation
typically involves the cultivation of plant cells or tissues in vitro (in a controlled environment outside of
their natural habitat) under optimized conditions for growth and production.
Mammalian cell fermentation
Mammalian cell fermentation or animal cell culture fermentation is a biotechnological process that
involves the cultivation of mammalian cells in vitro (outside of their natural environment) to produce
biopharmaceuticals, vaccines, viral vectors, and other protein-based products.
What are the main Fermentation types?
Batch Fermentation
- Description: Batch fermentation is one of the simplest and oldest forms of fermentation.
Microorganisms are cultivated in a closed vessel until the process is completed, after which the
product is harvested, and the vessel is emptied for the next batch. - Advantages: Easy to set up and operate, suitable for small-scale production, flexible in terms of
product variety. - Limitations: Time-consuming due to the need for sequential batches, inconsistent product
quality between batches, labor-intensive for large-scale production.
Continuous Fermentation
- Description: In continuous fermentation, fresh nutrient medium is continuously fed into the
fermenter while the product is simultaneously harvested. This allows for a steady-state
operation without the need to stop for batch changes. - Advantages: Higher productivity, better control over fermentation conditions, reduced labor
and downtime, suitable for large-scale production. - Limitations: Complex setup and operation, higher initial investment costs, risk of contamination
due to continuous operation.
Fed-Batch Fermentation
- Description: Fed-batch fermentation is a hybrid of batch and continuous fermentation.
Nutrients are added incrementally during the fermentation process to maintain optimal growth
conditions and extend the fermentation time. - Advantages: Offers better control over nutrient supply, allows for higher cell densities and
product concentrations compared to batch fermentation, suitable for high-value products. - Limitations: Requires careful monitoring and control of nutrient addition, and longer
fermentation times compared to batch fermentation.
Solid-State Fermentation
- Description: In solid-state fermentation, microorganisms grow on a solid substrate without a
free-flowing liquid medium. This method is commonly used to produce enzymes, organic acids,
and some food products. - Advantages: Lower water consumption, reduced contamination risk, easier downstream
processing, suitable for niche products. - Limitations: Limited to certain types of microorganisms and substrates, slower growth rates compared to submerged fermentation, challenges in scaling up production.
Submerged Fermentation
- Description: Submerged fermentation, also known as liquid-state fermentation, involves the
cultivation of microorganisms in a liquid nutrient medium. It is widely used for the production
of various industrial enzymes, antibiotics, organic acids, and biofuels. - Advantages: Well-established technology, high growth rates and product yields, easier to scale
up for large-scale production, suitable for a wide range of microorganisms and products. - Limitations: Higher energy and nutrient requirements compared to solid-state fermentation,
potential foaming issues, challenges in downstream processing and product recovery.
Growth Media
Water
Serves as the solvent for all other components of the fermentation medium and provides the necessary
hydration for microbial growth and metabolic reactions.
Samples: purified water, water for injection.
Carbon Source
Provides energy and carbon for microbial growth and product formation. Common carbon
sources include sugars (glucose, sucrose, lactose), starches, organic acids, and alcohols.
Samples: glucose, glycerol, molasses, corn starch, whey, vegetable oil, alcohols, cellulose.
Nitrogen Source
Essential for protein synthesis and cell growth. Common nitrogen sources include ammonium
salts (ammonium sulfate, ammonium chloride), amino acids, peptides, and complex nitrogenous compounds
(yeast extract, peptones).
Samples: Ammonia, Urea, Casein hydrolysate, yeast extract, malt extract, corn steep liquor, soybean
meal&flour, fish meal, cottonseed nutrients.
Minerals and Salts
Provide essential ions and trace elements required for enzymatic reactions, cell structure,
and osmotic balance. Examples include phosphates, sulfates, chlorides, calcium salts, magnesium salts, and
trace metal ions (iron, zinc, copper, manganese).
Trace Elements
Required in small amounts for specific metabolic pathways and enzymatic functions. Examples
include molybdenum, selenium, cobalt, and nickel.
Vitamins
Serve as cofactors for enzymatic reactions and are essential for cell metabolism and growth.
Common vitamins added to fermentation media include biotin, riboflavin, thiamine, pantothenic acid, and folic
acid.
Complex Organic Supplements
Enhance cell growth and productivity by providing additional nutrients and
growth factors. Examples include yeast extract, peptones, casamino acids, soybean meal, and corn steep liquor.
pH Buffers
Maintain the pH of the fermentation medium within the optimal range for microbial growth and
product formation. Common pH buffers include phosphate buffers, acetate buffers, citrate buffers, and
carbonate buffers.
Antifoam Agents
Prevent excessive foaming during fermentation, which can disrupt mixing and gas exchange.
Common antifoam agents include silicone-based compounds, mineral oils, and fatty acids.
Inducers and Regulatory Compounds
Used to trigger specific metabolic pathways or regulate gene expression
to produce desired products. Examples include inducers for recombinant protein expression and regulatory
compounds for secondary metabolite production.
Fermenters (bioreactors) types
Stirred Tank Bioreactors
Stirred tank bioreactors are the most common type of fermenter used in
industrial applications. They consist of a cylindrical vessel equipped with an agitator (usually a stirrer or
impeller) to provide mixing and aeration. Stirred tank bioreactors are versatile and can be used for a
wide range of microbial and cell culture processes.
Air-Lift Bioreactors
Air-lift bioreactors use air or gas injection to create circulation and mixing within
the vessel. They typically consist of a draft tube that generates upward flow and a riser section where
gas is introduced. Air-lift bioreactors are suitable for processes where gentle agitation is required and
are often used in aerobic fermentation processes.
Bubble Column Bioreactors
Bubble column bioreactors rely on the upward flow of gas bubbles to
provide mixing and aeration. They consist of a vertical column filled with liquid medium, into which gas
is sparged from the bottom. Bubble column bioreactors are simple in design and are often used for
aerobic fermentation processes in which high oxygen transfer rates are required.
Packed Bed Bioreactors
Packed bed bioreactors contain a solid matrix (such as beads or particles)
immobilized within the vessel, providing a surface for microbial attachment and growth. The liquid
medium flows through the packed bed, allowing for efficient contact between the cells and the
substrate. Packed bed bioreactors are commonly used for immobilized cell or enzyme processes.
Fluidized Bed Bioreactors
Fluidized bed bioreactors involve suspending solid particles within the vessel
and passing the liquid medium through the bed at a velocity sufficient to fluidize the particles. This
creates a highly turbulent and well-mixed environment, ideal for processes requiring high mass transfer
rates. Fluidized bed bioreactors are used in applications such as wastewater treatment and biocatalysis.
Membrane Bioreactors (MBRs)
Membrane bioreactors combine biological treatment with membrane
filtration in a single unit. They consist of a bioreactor vessel where microorganisms degrade organic
matter, coupled with membrane modules that separate the treated water from the biomass. MBRs are
commonly used in wastewater treatment applications.