Department of Biotechnology

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E-Module on

Techniques In Fermentation Technology

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• Resource Person- Dr. Jitender Kumar
• HOD, Biotechnology

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Introduction

• Any process mediated by living organism or their component in which a product of economical value is obtained is called fermentation.
• The science of fermentation is known as Zymology.
• Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes.
• Fermentation in food processing is the process of converting carbohydrates to alcohol or organic acids using microorganisms yeasts or bacteria.
• Fermentation usually implies desirable action of microorganisms.

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Commercial Fermentations

• Microbial biomass/microbial cells
• Microbial enzymes
• Microbial metabolites
• Recombinant products
• Biotransformation

Historical Development�

• The French chemist Louis Pasteur founded Zymology (study of fermentation), when in 1856 he connected yeast to fermentation process.
• Gives Pasteur effect and first synthetic media for alcohol production.
• Since ancient times, humans have exploited the fermentation process and the earliest archaeological evidence of fermentation is 13,000-year-old residues of a beer found in a cave near Haifa in Israel.
• Another early alcoholic drink made from fruit, rice, and honey, dates from 7000-6600 BC, in the Neolithic Chinese village of Jiahu and wine making dates from 6000 BC in Georgia.
• Seven-thousand-year-old jars containing the remains of wine, now on display at the University of Pennsylvania were excavated in the Zagros Mountains in Iran.
• There is strong evidence that people were fermenting alcoholic drinks in Babylon 3000 BC, ancient Egypt 3150 BC, pre-Hispanic Mexico 2000 BC and Sudan 1500 BC.

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Historical Development

• In the beginning, fermentation was mainly associated with the preparation of spiritual drinks, but later on it was used for other purposes also.
• Traditional fermentation technology is more than 3000 year old in India as mentioned in ancient literature.
• A sweet substance known as Soma Juice prepared by the Vedic Aryans is supposed to be the first product of fermentation in India.
• The Rigveda (1500 BC) shows that fermentation technology took its first step in connection with the preparation of Soma Juice in India.
• There is also another drink known as Sura (wine/beer) prepared by fermentation. So, it is believed that acetic fermentation was known to India since the early times.
• Curd is another very popular fermentation product described in the Rigveda . It still remains a popular food and the technology of curdling milk is also found in a number of texts associated with Yajurveda.

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Historical Development�

• The term fermentation is derived from the Latin word Fermentum that stands for boiling.
• Food fermentation is the conversion of sugars and other carbohydrates into alcohol, organic acids and carbon dioxide. All three products have showed their importance in human uses.
• The production of alcohol is made use of when fruit juices are converted to wine, when grains are made into beer and when foods rich in starch, such as potatoes, are fermented and then distilled to make spirits such as gin and vodka.

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Bacterial fermentations product�

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• Pyruvate formed by the catabolism of glucose is further metabolized by pathways which are characteristic of particular organism.
• End products are shown in figure.

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Schematic representation of the common types of fermentation, �the microorganisms involved, and the end products�

Production of Fermented Foods by Bacteria and Yeast�

Fermentation

Design of an Ideal Fermenter�

Components of an Ideal Fermenter �

Fermenter Control Units�

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Fermentation is classified on the basis of substrate used

1. Solid state fermentation (SSF)
2. Submerged fermentation (SmF)
1. Fermentation is the chemical transformation of organic substances into simplex compounds by the action of enzymes which are produced by microorganism such as yeast, molds or bacteria.
2. In another words, fermentation is the technique of biological conversion of complex substrates into simple compounds by various microorganism. 

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Solid State Fermentation (SSF) �

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1. Solid state fermentation has been defined as the fermentation process occurring in the absence or near absence of free water utilizing the solid substrate.
2. It is a biomolecule manufacturing process used in the food, pharmaceutical, cosmetic, fuel and textile industries. These biomolecules are mostly metabolites generated by microorganisms grown on a solid support selected for this purpose.
3. This technology for the culture of microorganisms is an alternative to liquid or submerged fermentation, used predominantly for industrial purposes.

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Why Solid State Fermentation ?�

• Simple and cost effective
• Less effluent release, reduce pollution
• Aeration is easy
• Resembles the natural habitat of some fungi and bacteria
• SSF utilizes solid substrate, thus nutrient rich waste materials can be easily recycled as substrate
• Substrate are used very slowly and steadily so the same substrate can be used for longer fermentation period
• SSF is best suited for fermentation techniques involving fungi and microorganism that require less moisture content

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Factors Involved in SSF Process

• Factors Involved in SSF Process

1. Selection of Micro-organisms: This is one of the key factor for improved yields of the product. Bacteria, Yeast and Filamentous Fungi can be used. Filamentous Fungi has shown better results growing in the solid substrate fermentation.

2. Substrate: Substrate also plays important role in determining the growth of micro-organisms, there by increasing the product yield. Substrate is chosen such a way that it should provide physical support as well as nutrients to the growing culture. Substrate is of two types:

• One is Specific substrate, which requires suitable value-addition and / or disposal.
• The second is for producing a specific product from a suitable substrate.

3. Process Optimization: It is the optimization of physico-chemical and biochemical parameters which includes size, initial moisture, pH and pre-treatment of the substrate, Relative humidity, temperature of incubation, agitation and aeration and age and size of the inoculum. Nutrient Supplementation such as N, P and trace elements and supplementation of additional carbon source and inducers. Extraction of product and its purification.

4. Product Isolation & Purification

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Applications of Solid State fermentation �

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• Solid State fermentation is being employed in various fields ranging from pharmacology to bioremediation, covering various aspects of biodiversity conservation.
• Applications of Solid State fermentation --
• Production of Industrial Enzymes as almost all the known microbial enzymes can be produced under SSF systems. Enzymes of industrial importance, like proteases, cellulases, ligninases, xylanases, pectinases, amylases, phenolic acid esterases, microbial rennets, oligosaccharide oxidases etc. using SSF systems.
• Production of Bio pesticides -- The infamous Bacillus thurengenesis (Bt)’s protein can be produced in large scale in order to address the issues of pest attacks-yield damage.

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Applications of Solid State fermentation �

Problems in Solid state (substrate) fermentation�

• Heat Transfer: One of the main difficulty is to control the temperature during the fermentation process.
• Heat is generated during the metabolic activities of microorganisms, since the substrate used has low thermal conductivity heat removal will be slow.
• When the heat generated goes beyond certain level, which will result in product denaturation and will effect the growth of microbe , ultimately ending up in reduction in yield and quality of the product.

2.Submerged Fermentation�

• It is a techniques of cultivation of microorganism in liquid broth which breaks down the nutrient to release the desired bio-active compound into solution. In this method, selected microorganism are grown in closed vessels containing a broth rich in nutrients and high concentration of oxygen. In SmF substrate are utilized quite rapidly hence need to be constantly replaced or supplemented with nutrients. Bacteria that requires high moisture content or high water activity are best suited for submerged fermentation.
• Applications of Submerged Fermentation : It utilizes free flowing liquid substrates, such as molasses and broths. The bioactive compounds are secreted into the fermentation broth.. This fermentation technique is best suited for microorganisms such as bacteria that require high moisture. An additional advantage of this technique is that purification of products is easier.

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Submerged Fermentation

• More that 75% of the industrial enzymes are produced using SmF, one of the major reasons is that SmF supports the utilization of genetically modified organisms to a greater extent than SSF.
• In SmF, the accumulation of variety of intermediate metabolites results in lowered enzyme activity and production efficiency.
• Based on research, certain bioactive compounds have found to be produced in higher quantities in SSF, whereas other compounds have been extracted using SmF

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Submerged Fermentation and Solid State Fermentation

References

• General Microbiology by Stainier
• Biotechnology: Expanding Horizon – B.D. Singh (Kalyani Publication)
• Biophysical and Biochemical Technology – Wilson and Walker (Cambridge University Press)
• Principle of Gene Manipulation and Genomics – Primrose (Blackwell Publication)
• General Microbiology by Stainier
• Biotechnology: Expanding Horizon – B.D. Singh (Kalyani Publication)
• Biophysical and Biochemical Technology – Wilson and Walker (Cambridge University Press)
• Principle of Gene Manipulation and Genomics – Primrose (Blackwell Publication)

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��THANK YOU