The degradation of phytate by microbial and wheat phytases is dependent on the phytate matrix and the phytase origin

BACKGROUND: Phytases increase utilization of phytate phosphorus in feed. Since wheat is rich in endogenous phytase activity it was examined whether wheat phytases could improve phytate degradation compared to microbial phytases. Moreover, it was investigated whether enzymatic degradation of phytate is influenced by the matrix surrounding it. Phytate degradation was defined as the decrease in the sum of InsP(6) + InsP(5). RESULTS: Endogenous wheat phytase effectively degraded wheat InsP(6) + InsP(5) at pH 4 and pH 5, while this was not true for a recombinant wheat phytase or phytase extracted from wheat bran. Only microbial phytases were able to degrade InsP(6) + InsP(5) in the entire pH range from 3 to 5, which is relevant for feed applications. A microbial phytase was efficient towards InsP(6) + InsP(5) in different phytate samples, whereas the ability to degrade InsP(6) + InsP(5) in the different phytate samples ranged from 12% to 70% for the recombinant wheat phytase. CONCLUSION: Wheat phytase appeared to have an interesting potential. However, the wheat phytases studied could not improve phytate degradation compared to microbial phytases. The ability to degrade phytate in different phytate samples varied greatly for some phytases, indicating that phytase efficacy may be affected by the phytate matrix. (C) 2011 Society of Chemical Industry