Fermentative activity of microbes is utilized industrially to get a number of products. The two common ones are alcoholic fermentation and antibiotics.
Methodology:
For any new industrial utilization of a microorganism activity, the technology passes through 3 stages—laboratory scale, pilot plant scale and producing unit. Formation from laboratory scale to producing unit is named scaling up.
1.Laboratory Scale:
Soon after the discovery of use of a microorganism, the maxiÂmum number of strains is searched and the most suitable strain is selected and multiplied. A laboratory scale apparatus/plant is manufactured. It has a glass fermentor (fermenter). Ultimately, the laboratory scale process is finalized.
2. Pilot Plant Scale:
It is intermediate stage wherever operating of the laboratory scale method is tested value and qualities of the merchandise area units are evaluated. Glass vessels are replaced by metallic containers. The container where fermentation is carried out is called bioreactor or fermentor. Aeration system, pH corrections and temperature adjustments are perfected.
3. Manufacturing Unit:
Its size is decided by the economics worked at in course of the pilot plant scale process. Bioreactor or fermentor is often large. Microorganisms are added in bioreactors in three ways:
1-System of support growth or onthe exterior of nutrient medium,
2-System of suspended or eliminated in nutrient medium,
3-System of column or immobilized growth where microorganisms which are placed in calcium alginate beads are maintained in columns.
Alcoholic Fermentation:
Louis Pasteur found for the first time that beer and butter milk are produced due to activity of Yeast and Yeast-like microorganisms. Yeast species used in alcoholic fermentation are Saccharomyces cerevisiae (Brewer’s Yeast), S. ellipsoidens (Wine Yeast), S. sake (Sake Yeast) and S. pireformis (Ginger Beer/Ale Yeast). The nutrient medium is barley malt for beer, fermented rye malt for gin, fermented rice for sake, cashew-apple for fenny, potato for vodka, fermented cereals for whisky, fermented molasses for rum and fermented juices for wines and brandy.
1. Yeast does not possess sufficient diastase/amylase. Therefore, either 1% malt or Rhizopus is used when the nutrient medium consists of complex carbohydrates as present in cereals and Potato. Hydrolysis of starch is administered in separate tank at heat (55°C) for half-hour. The crushed food mixed with quandary for getting malt is termed mash. The sugared nutrient medium before alcoholic fermentation is termed wort.
2. Bioreactor/fermentation tank is sterilized with the assistance of steam under serious pressure. The liquid nutrient medium or wort is added into the tank and sterilized similarly. It is then allowed to cool.
3. Once the liquid nutrient medium is cooled down enough to cheap temperature, it’s inoculated with applicable strain of Yeast through support growth system (on the surface) or suspended growth system (inside the wort). Fermentation happens in 3 ways:
1- Continuous Process:
There is a removal of a portion of fermented liquor/wash on daily basis and more nutrient is added.
2- Fed Batch Process:
Nutrient is fed on daily basis in small amounts in the fermenter so as to modify the working of the fermenting microbe without any prevention.
3- Immobilized Yeast:
Recently yeast is being used in immobilized condition in calcium alginate beads. The technique is 20 times more efficient.
Both Beer and Wine are filtered, pasteurized and bottled without further distillation. Higher alcoholic content is generally achieved through direct addition of alcohol. Hops are added to wort during preparation of beer. Bye-products of alcoholic fermentation are CO2 and Yeast. A number of other chemiÂcals can be formed with the change of nutrient medium, pH and aeration – n-propanol, butanol, amyl alcohol, phenylethanol, glycerol, acetic acid, pyruvic acid, succinic acid, lactic acid, caproic acid, caprylic acid, ethyl acetate, acetaldehyde, diacetyl, and hydrogen sulphid.
