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Imprint
Phytase production by solid state fermentation and enzyme immobilisation by spray drying
Project
Project code: MRI-LBV-08-UNESP-Phytase
Contract period: 01.10.2012
- 30.09.2016
Purpose of research: Applied research
Phytases are a special group of phosphatases, that are added to pig and poultry feed in order to make the organically-bound phosphate available to the animals. In recent years phytases became interesting for application in food processing. A reduction in the phytate content of plant-based food result in an improvement of mineral bioavailability. Furthermore, phytases can be used in the production of functional foods. Last but not least technical improvements in food processing can be achieved by adding phytases. Phytase with all desired properties for the biotechnological application have not be found in nature. Using solid state fermentation agricultural byproducts could be used to grow phytase-producing fungi. For a biotechnological application of the enzymes a high stability is of utmost importance. Immobilisation is one way to increase enzyme stability. Therefore, the effect of spray drying on phytase stability will be studied.
The use of filamentous fungi for the phytase production through solid--state fermentation has gained much interest for research in the last years. The capability to produce extracellular phytases depends on the fungal strain used for fermentation and the fermentation conditions. Especially the composition of the medium used for fermentation was shown to significantly affect phytase production. Phytase synthesis was shown to be stimulated in the absence of inorganic phosphates and repressed in the presence of high concentrations of inorganic phosphate. However, low concentrations of inorganic phosphate in the growth medium were needed to guarantee fungal growth in the beginning of fermentation. Since many phytases do not exhibit sufficient storage stability, spray drying was used to convert the enzyme suspension into a storable form. Different drying adjuvants such as corn starch, dextran, glucose, maltodextrin, mannitol, and trehalose in concentrations between 0.5 and 3.5% (w/w) were studied. Spray drying was performed using a fixed air flow and varying the air temperature at the entrance of the drying chamber (between 140 and 220°C) as well as the flow of the enzyme suspension (between 10 and 30%). Optimal drying conditions in respect to enzyme activity recovery were shown to be dependent on the enzyme source and the purity of the enzyme. The drying process did not significantly affect the physicochemical properties of the studied phytases.
Section overview
Subjects
- Animal nutrition
- Food Processing
- Biotechnology
Framework programme
Funding programme
Excutive institution
MRI - Department of Food and Bio Process Engineering (MRI-LBV)
