Isolation and Identification Of Ascomycetous Yeast Producing Phytase

Abstract

The objective of the study was to isolate, identify and characterize phytase producing yeast. The yeast was isolated from various resources, and the identification of yeast was conducted by the sequencing of the ITS region. Of 41 isolates, 24 isolated produced phytase. The highest phytse producing yeast was identified as Candida natalensis YEG 132, Saturnispora quitensis YEg 135, and Candida albicans YEg 226. These isolates were able to use various carbon and nitrogen sources. The maximum phytase production depends on isolates, media composition, pH and incubation temperature. Temperature affected phytase production. All isolates produce the highest phytase was at 30°C. Increased temperature to 35° C and 40°C inhibits phytase production by all strains. S. quitensis was the highest isolate inhibited by an increase of incubation temperature. The pH of cultures affects phytase production and varies depending on isolate. S. quitensis and Candida natalesis produced the highest phytase activities at pH 5.0, while C. albicans was at pH 6.0. All isolates were able to assimilate glucose, dextrose, sucrose, xylose and lactose. In general, glucose was the best carbon source for phytase activity. But each isolate has its preferential on carbon sources. S. quitensis produced the highest phytase on glucose, but not on dextrose. Each isolate has preferential on nitrogen sources. Yeast extract was the best N-sources for C. albicans, while ammonium sulfate was best for C. natalensis, S. quitensis. Ammonium nitrate was not favorable for phytase production by C. natalensis. Candida natalensis YEG 132, Saturnispora quitensis YEg 135, and Candida albicans YEg 226 was a good candidate for phytase production.