Fermentation Introduction PDF

4.6 Fermentation 4.6 Fermentation 4.6 Fermentation  Fermentation typically refers to the conversion of sugar to alcohol using yeast under anaerobic conditions. A more general definition of fermentation is the chemical conversion of carbohydrates into alcohols or acids.  The science o...

4.6 Fermentation 4.6 Fermentation 4.6 Fermentation  Fermentation typically refers to the conversion of sugar to alcohol using yeast under anaerobic conditions. A more general definition of fermentation is the chemical conversion of carbohydrates into alcohols or acids.  The science of fermentation is known as zymology.  Fermentation usually implies that the action of the microorganisms is desirable, and the process is used to produce alcoholic beverages such as wine, beer, and cider.  Fermentation is also employed in preservation to create lactic acid in sour foods such as pickled cucumbers, kimchi and yogurt.  Fermented foods can help to reduce high cholesterol levels in our blood, it strengthens and supports our digestive and immune systems--- thereby helping us to fight off and prevent diseases, like cancer. 4.6 Fermentation Fermentation is defined as the biochemical process by which organic compounds can be the electron donor and the electron acceptor at the same time. In fermentation, the final electron acceptor is an organic compound, unlike in aerobic respiration where the final electron acceptor is oxygen. For example, in lactic acid fermentation, the final electron acceptor is pyruvic acid.  Fermentation allows the production of a small amount of ATP without oxygen. 4.6 Fermentation 4.6 Fermentation 4.6 Fermentation Organisms responsible for fermentation Bacteria: Most important are LAB followed by Acetobacter species Yeasts: Most important are Saccharomyces. Yeast produce enzymes that favour desirable chemical reactions such as leavening of bread, production of alcohol etc., Moulds: Penicillium helps in flavouring of cheeses.some moulds produce enzymes 4.6 Fermentation 4.6 Fermentation Fermentation allows glycolysis to continue. Fermentation allows glycolysis to continue making ATP when oxygen is unavailable. Fermentation is an anaerobic process. – occurs when oxygen is not available for cellular respiration – produce less ATP than aerobic respiration 4.6 Fermentation Fermentation allows glycolysis to continue making ATP when oxygen is unavailable. NAD+ is recycled to glycolysis 4.6 Fermentation There are 2 types of fermentation Named for the products produced – Lactic acid fermentation – Alcoholic fermentation 4.6 Fermentation Lactic acid fermentation occurs in muscle cells. – glycolysis splits glucose into two pyruvate molecules – pyruvate and NADH enter fermentation – energy from NADH converts pyruvate into lactic acid – NADH is changed back into NAD+ 4.6 Fermentation Energy and Exercise Quick Energy 1. Cells contain only enough ATP for a few seconds of intense activity 2. Then cells rely on lactic acid fermentation (can supply for about 90 seconds) 3. Lactic acid build-up causes burning in muscles. Only way to get rid of lactic acid is chemical pathway that requires oxygen (why you breathe heavy after heavy excercise.) 4.6 Fermentation Build up of lactic acid in muscles cause burning sensation 4.6 Fermentation Fermentation and its products are important in several ways. Alcoholic fermentation is similar to lactic acid fermentation. – glycolysis splits glucose and the products enter fermentation – energy from NADH is used to split pyruvate into an alcohol and carbon dioxide – NADH is changed back into NAD+ – NAD+ is recycled to glycolysis 4.6 Fermentation 4.6 Fermentation Yeast do alcoholic fermentation Fermentation is used in food production. – yogurt – cheese – bread 4.6 Fermentation In cheese making, fungi or bacteria are added to large vats of milk. The microorganisms carry out lactic acid fermentation, converting some of the sugar in the milk to lactic acid. 4.6 Fermentation Fermentation is the chemical transformation of organic substances into simplex compounds by the action of enzymes, complex organic catalysts which are produced by microorganism such as yeast, molds or bacteria. In another words, fermentation is the technique of biological conversion of complex substrates into simple compounds by various microorganism. FERMENTATION, classified on the basis of substrate used 1.Solid state fermentation (SSF) 2.Submerged fermentation (SmF) 4.6 Fermentation Development of this fermentation techniques has leads to industrial level production of bioactive compounds such as antibiotics, pigments, antioxidants, antitumor agent, bio- surfactants, bioactive peptides etc. The metabolism exhibited by microorganism is different in SSF and SmF. 4.6 Fermentation 4.6 Fermentation Substrate Used 4.6 Fermentation  Microoorganisms are used extensively to provide a vast range of products and services (Table 4.1).  They have proved to be particularly useful because of the ease of their mass cultivation, speed of growth, use of cheap substrates (which in many cases are wastes) and the diversity of potential products.  Their ability to readily undergo genetic manipulation has also opened up almost limitless further possibilities for new products and services from the fermentation industries. 4.6 Fermentation