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BISC209/F13: Lab3: Difference between revisions
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→Community Physiological Profile of Starch Digesters, Cellulolytic Bacteria, and Phosphate Solubilizing Bacteria: Background
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Some animals can digest cellulose with the help of symbiotic microorganisms that live in their guts. For example some termites contain flagellate protozoa in their hind guts that produce cellulases while other termites and cows rely on gut bacteria. Fungi are very good at breaking down cellulose, just consider the shelf mushrooms that help degrade fallen trees. Humans can digest cellulose to some extent, but cellulose consumed by humans as food is largely undigested and acts as a hydrophilic bulking agent for feces ("dietary fiber"). Soil microorganisms capable of catabolizing cellulosic material contribute to the carbon cycle and, ultimately, contribute to the release of CO<sub>2</sub>to the atmosphere--- making it available for re-uptake by plants. '''Cellulolysis''' is the process of hydrolytic break down of cellulose into smaller polysaccharides called cellodextrins or complete break down into glucose units. Because cellulose has a somewhat complex structure, cellulolysis is relatively difficult compared to the breakdown of other polysaccharides. The enzymes used to cleave the glycosidic linkage in cellulose are glycoside hydrolases. They include endo-acting cellulases and exo-acting glucosidases. Such enzymes are usually secreted as part of multienzyme complexes. Soil bacteria and symbiotic anaerobic bacteria (like the ''Cellulomonas'' group of bacteria) are among those known to produce and secrete these enzymes. <BR> | Some animals can digest cellulose with the help of symbiotic microorganisms that live in their guts. For example some termites contain flagellate protozoa in their hind guts that produce cellulases while other termites and cows rely on gut bacteria. Fungi are very good at breaking down cellulose, just consider the shelf mushrooms that help degrade fallen trees. Humans can digest cellulose to some extent, but cellulose consumed by humans as food is largely undigested and acts as a hydrophilic bulking agent for feces ("dietary fiber"). Soil microorganisms capable of catabolizing cellulosic material contribute to the carbon cycle and, ultimately, contribute to the release of CO<sub>2</sub>to the atmosphere--- making it available for re-uptake by plants. '''Cellulolysis''' is the process of hydrolytic break down of cellulose into smaller polysaccharides called cellodextrins or complete break down into glucose units. Because cellulose has a somewhat complex structure, cellulolysis is relatively difficult compared to the breakdown of other polysaccharides. The enzymes used to cleave the glycosidic linkage in cellulose are glycoside hydrolases. They include endo-acting cellulases and exo-acting glucosidases. Such enzymes are usually secreted as part of multienzyme complexes. Soil bacteria and symbiotic anaerobic bacteria (like the ''Cellulomonas'' group of bacteria) are among those known to produce and secrete these enzymes. <BR> | ||
'''Phosphate Solubilizing Activity''': Phosphorus is one of the major nutrients that limits plant growth. It is important in physiological activities such as photosynthesis, root development, cell division, and for efficient use of carbon substrates. Most phosphorus is found in an insoluble form; thus, the conversion of insoluble phosphorus into soluble forms that can be absorbed by plants is an important interaction between plants and phosphate solubilizing bacteria. The fact that phosphate solubilizing bacteria process phosphate ''extracellularly'', means that | '''Phosphate Solubilizing Activity''': Phosphorus is one of the major nutrients that limits plant growth. It is important in physiological activities such as photosynthesis, root development, cell division, and for efficient use of carbon substrates. Most phosphorus is found in an insoluble form; thus, the conversion of insoluble phosphorus into soluble forms that can be absorbed by plants is an important interaction between plants and phosphate solubilizing bacteria. The fact that phosphate solubilizing bacteria process phosphate ''extracellularly'', means that these bacteria can meet their own needs for a useable form of this essential nutrient AND they allow other bacteria in the community to find phosphorus in a useable post-processed form. | ||
Because soil is, in some ways, a non-renewable resource, the activity of the microbial population in maintaining soil quality is of paramount importance and a diverse and rich population of phosphate solubilizing bacteria play a crucial role in the improvement and repair of soil health destroyed by years of environmental abuse. <BR><BR> | Because soil is, in some ways, a non-renewable resource, the activity of the microbial population in maintaining soil quality is of paramount importance and a diverse and rich population of phosphate solubilizing bacteria play a crucial role in the improvement and repair of soil health destroyed by years of environmental abuse. <BR><BR> | ||
