University:
California State University, Northridge
Course:
BIOL 101 | General Biology
Academic year:

2024
Views:

434

Pages:

1
Author:

Tommy B.

FERMENTATION PATHWAY Emden-Meyerhof-Parnas Line (EMP) This reaction is called glycolysis which contain process of the anaerobic breakdown of sugar to acid Pyruvate is carried out by most bodies from high to low levels low. This reaction happen in cytoplasm and without oxygen as the electron acceptor but other substances. Facultative microbes anaerobes (Saccharomyces cerevisiae) will carry out sugar fermentation anaerobes into alcohol and CO2. Lactobacillus spp. as homofermentative anaerobically breaks down sugar into lactic acid. And obligate microbes anaerobes such as Clostridium spp. breaks down sugar into acetone, butanol, butyrate. Aerobic microbes carry out the glycolysis process as the first part of anaerobic breakdown of carbohydrates, which will be passed on to the parts the second is aerobic. In the muscles of humans and animals that lack movement it will lactic acid accumulates because glycolysis does not continue to aerobic levels but rather to lactic acid. Microbes that carry out fermentation via glycolysis produces only 2 moles of ATP from each glucose metabolized. Entner-Doudoroff (ED) pathway This reaction is carried out by several microbes including Pseudomonas spp. which can form alcohol from sugar via this route. On each The breakdown of 1 mole of glucose also produces 1 ATP, 1 NADH2 and 1 NADPH2. In P. lindneri 2 pyruvic acids are broken down into 2 ethanol and 2 CO2; currently in other Pseudomonas 2 pyruvic acid is converted into 1 ethanol, 1 acid lactate and 1 CO2. Hexose Mono Phosphate (HMP) Pathway This reaction is useful for forming pentose sugars and others, for biosynthesis requirements. The reaction takes place via the C5 sugar, ribulose 5-phosphate, which is a precursor of ribose sugar, deoxyribose, components of nucleic acids, aromatic amino acids, enzymes, ATP, NAD, FAD and so on. HMP does not directly produces energy, but mainly forms NADPH2. Heterofermentative Pathways of Lactic Acid Bacteria The group of lactic acid bacteria besides producing lactic acid homofermentative (e.g. Lactobacillus spp.), also heterofermentative (eg Leuconostoc spp., Streptococcus spp., etc.). In fermentation Heterofermentation, apart from lactic acid, also produces acetic acid, ethanol and CO2. Anaerobic Pathway of Pyruvic Acid Metabolism Many anaerobic organisms have different enzymes used in the conversion of pyruvic acid. Clostridium depending on the species, can convert pyruvic acid into butyric acid, acetic acid, acetone, butanol, ethanol, CO2, and H2. Enteric bacteria such as Escherichia coli and Aerobacter aerogenes can convert pyruvic acid into succinic acid, acetate, lactic acid, ethanol, CO2, and H2 (or formate). Aerobacter aerogenes also produces 2,3-butyleneglycol. Salmonella sp. have the same metabolic patternwith Escherichia coli, but produces more formic acid, thanon H2 and CO2 as in Escherichia coli.