TNO Discovers Novel Classes of Phytases

Phytase is produced commercially by microbial fermentation using the fungus Aspergillus niger and other micro-organisms using a variety of different phytase genes. In view of the commercial importance of this enzyme, industry is continuously looking for genes coding for phytases that allow them freedom to operate. This is the case for the new fungal phytases discovered by TNO.

Building upon its extensive know-how in the area of fungal molecular genetics, TNO identified the new potential phytases by using fungal genome mining approach. "The increasing availability of fungal genomes has given fungal biotechnology a new boost" states Peter Punt, project manager for the phytase project at TNO. Using this approach several potential phytase genes belonging to new classes of phytases were discovered. One class is distantly related to known fungal phytases and the other embraces fungal phytases showing the highest homology to bacterial phytases. In collaboration with Dyadic NL, these new phytase gene candidates have been expressed in Chrysosporium lucknowense and shown to be functionally active. A patent application regarding to these discoveries has been filed.

Phytases are enzymes that enhance the nutritional value of animal feed and diminish the phosphate burden to the environment by releasing bound phosphates from feed ingredients of vegetable origin. Phytase hydrolyzes phytic acid (phytate), which is the principle storage form of phosphorus in feedstocks of plant origin and can not be digested by gastric farm animals such as pigs and poultry. Phytate also forms complexes with proteins, digestive enzymes and minerals, and as such is considered to be an anti-nutritional factor. The use of phytase eliminates the need to supplement feeds with inorganic sources of essential phosphate. Thus, by releasing bound phosphate in feed ingredients, phytase makes more phosphate available for bone growth, and reduces the amount excreted into the environment.