Novel biosensors for quantitative phytic acid and phytase measurement

Phytase (EC 3.1.3.26) and phytic acid (myo-mositol hexaphosphate) play an important environmental role in poultry industry and have a health aspect in food industry. Novel biosensors have been developed for simple, one step quantitative phytic acid and phytase detection. A system based on the sequentially acting enzyme phytase and pyruvate oxidase (POD) was employed for the development of phytase and phytic acid biosensors. Poly(carbamoylsulphonate) (PCS) hydrogel immobilized POD electrode was applied for the detection of phytase. It was based on the indication of phosphate ions produced by the hydrolysis of phytic acid. The phytase biosensor showed a linear response ranging from 0.5 to 6.0 units/ml. A bi-enzyme sensor based on co-immobilization of phytase and POD was developed for the detection of phytic acid on the basis of amperometric detection of the enzymatically-generated hydrogen peroxide at 0.6 V versus Ag/AgCl. It showed a linear response ranging from 0.2 to 2.0 mM with a detection limit of 0.002 mM. (C) 2003 Elsevier B.V. All rights reserved.