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Cellulose is a polymer made with repeated glucose units bonded together by beta-linkages. Humans and many animals lack an enzyme to break the beta-linkages, so they do not digest cellulose. Certain animals, such as termites can digest cellulose, because bacteria possessing the enzyme are present in their gut. Cellulose is insoluble in water.
Ribbon representation of the Streptomyces lividans β-1,4-endoglucanase catalytic domain - an example from the family 12 glycoside hydrolases [1]. Cellulase (EC 3.2.1.4; systematic name 4-β-D-glucan 4-glucanohydrolase) is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharides:
Cellulose for industrial use is mainly obtained from wood pulp and cotton. [6] Cellulose is also greatly affected by direct interaction with several organic liquids. [10] Some animals, particularly ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha.
A monogastric organism is contrasted with ruminant organisms (which have four-chambered complex stomachs), such as cattle, goats, and sheep. Herbivores with monogastric digestion can digest cellulose in their diets by way of symbiotic gut bacteria. However, their ability to extract energy from cellulose digestion is less efficient than in ...
Trichonympha is a vital part of the hindgut microbiota of these organisms. Lower termites and wood roaches have a diet composed almost exclusively of wood and wood-related items, such as leaf litter, [12] and therefore, need to digest large quantities of cellulose, lignocellulose and hemicellulose. [12]
Gluconeogenesis permits glucose to be synthesized from various sources, including lipids. [19] In some animals (such as termites) [20] and some microorganisms (such as protists and bacteria), cellulose can be disassembled during digestion and absorbed as glucose. [21]
Fermentation is crucial to digestion because it breaks down complex carbohydrates, such as cellulose, and enables the animal to use them. Microbes function best in a warm, moist, anaerobic environment with a temperature range of 37.7 to 42.2 °C (99.9 to 108.0 °F) and a pH between 6.0 and 6.4.
For instance, the formation of cellulose is repressed by high concentrations of glucose in the cytoplasm. On depletion of primary sources of glucose, enzymes to degrade more complex molecules such as cellulose and starch, are then released. Thus soluble sugars and amino acids are removed first from a leaf released from a tree. Starch is then ...