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Studies on the production and characterization of phytate degrading enzymes in Aspergillus niger

Gunashree, B. S. (2006) Studies on the production and characterization of phytate degrading enzymes in Aspergillus niger. PhD thesis, University of Mysore.


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Animal feed manufacturing is one of the important agro-industrial practices in most of the countries worldwide. Livestock practitioners are facing many problems associated with nutritional aspects due to anti-nutritional components such as phytic acid and other phenolic compounds that are predominant in the complex feed materials. Excretion of excess of minerals and other by-products poses a pollution threat to the surrounding environment. Phytic acid (myo- inositol hexakisphosphate), is a storage form of phosphorus in plant materials such as cereals, legumes and oil seeds that constitutes 1-2% by weight. Phytate- phosphorus accounts for 60 - 90% of the total phosphorus. Phosphorus bound to phytate is either non available or is available only in reduced quantities to monogastric animals such as poultry, swine and also to humans. This has forced the livestock rearers to supplement the feed with inorganic phosphates such as dicalcium or tricalcium phosphates, which are highly expensive. Further, undigested phytate- phosphorus is excreted by the monogastric birds and animals. Thus, high titres of phosphates in the environment leads to pollution of livestock areas, eutrophication of nearby water bodies that depletes oxygen content and thereby death of the aquatic animals. The negatively charged phytic acid binds to positively charged cations such as calcium, magnesium, manganese, zinc, iron and proteins and these metal salts are made unavailable to monogastrics. Hence phytic acid is considered to be an anti- nutritional factor in feed. The phytate- protein insoluble complexes reduce the bioavailability of basic amino acids in proteins. Phytic acid is also known to inhibit certain enzymes such as -amylase, trypsin, tyrosinase and pepsin. For the last two decades, researchers all over the world have shown considerable interest in developing an economically viable process for the removal of phytic acid or its degradation either chemically or enzymatically. Phytase enzyme hydrolyzes phytate and makes the bound phosphorus and other minerals available to the monogastric animals. Despite the voluminous literature on the sources of phytase, microbial source from Aspergillus is the most reliable one and highly characterized for application as a feed supplement.

Item Type: Thesis (PhD)
Uncontrolled Keywords: phytic acid Aspergillus niger phytase
Subjects: 600 Technology > 08 Food technology > 09 Food Microbiology
Divisions: Food Microbiology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 20 Jun 2008 04:29
Last Modified: 28 Dec 2011 09:34

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