Over the last 15 years, Huvepharma® has confirmed its place as a phytase supplier by commercialising OptiPhos® / Hostazym® P. OptiPhos® is known to be the fastest working phytase while providing reliable matrix values. However, like many other phytases, a coating is required to obtain heat stability up to 85oC. At higher temperatures, a post-pelleting liquid application (PPLA) is required. PPLA equipment is expensive and requires maintenance and quality control to ensure good performance so is not available in every feed mill. Using a phytase with intrinsic heat stability, allowing it to be dosed in the feed or a premix, is the ideal solution.
Searching for OptiPhos® Plus
In 2014, Huvepharma® initiated a project to screen for new phytases with a focus on finding a strain with uncompromised performance as well as intrinsic heat stability. The goal was to identify a granulate phytase thermostable up to 85oC, and to develop a coated version with increased thermostability up to 95oC.
Two development methods were followed:
- Screening of a completely new phytase (new gene, new production strain, new production process)
- Further investigation of the appA E. coli gene which is the origin of the current OptiPhos®, to explore additional characteristics
The process of exploring additional strain characteristics, as shown in Figure 1, involves making rationalised design modifications at gene level to create new strains with new characteristics. These new strains are then tested and evaluated. The most promising variants are subject to further modification until an ideal candidate is found.
The most promising phytases from both develoment methods were screened for their biochemical PPS (pH profile, pepsin resistance and speed of phytate hydrolysis) characteristics. In addition, liquid thermostability testing was carried out. The best candidates were selected and extensively screened in pelleting studies to evaluate their heat stability in feed. Finally, the selected strains were tested in animal performance studies.
The screening and testing of totally new phytase strains (as done in development method 1 above) uncovered some with good intrinsic heat stability, but (much) higher in-feed dosing was required to outperform OptiPhos®.
By starting from the appA E. coli gene (as done in development method 2), many of the desired characteristics were already present. Additional intrinsic heat stability with high phytate degradation levels, even at low doses, were found in four strains. Further testing and pelleting stability studies brought the number of potential new phytase candidates down to two. Multiple animal studies were conducted using the final two candidates, resulting in one clear winner: OptiPhos® Plus was born.