Characteristics of fungal phytases from Aspergillus fumigatus and Sartorya fumigata.

Aspergillus fumigatus phytase has previously been identified as a phytase with a series of favourable properties that may be relevant in animal and human nutrition, both for maximising phytic acid degradation and for increasing mineral and amino acid availability. To study the natural variability in amino acid sequence and its impact on the catalytic properties of the enzyme, we cloned and overexpressed the phytase genes and proteins from six new purported A. fumigatus isolates.

Paracoccus zeaxanthinifaciens sp. nov., a zeaxanthin-producing bacterium.

A comprehensive taxonomic re-evaluation was performed on the marine, zeaxanthin-producing bacterium formerly classified as [Favobacterium] sp. strain R-1 512 (ATCC 21588). This strain, together with two other previously described marine isolates, [Flavobacterium] strain R-1506 and Paracoccus sp.

The consensus concept for thermostability engineering of proteins: further proof of concept.

Previously, we calculated a consensus amino acid sequence from 13 homologous fungal phytases. A synthetic gene was constructed and recombinantly expressed. Surprisingly, consensus phytase-1 was 15-26 degrees C more thermostable than all parent phytases used in its design [Lehmann et al.

Engineering of phytase for improved activity at low pH.

For industrial applications in animal feed, a phytase of interest must be optimally active in the pH range prevalent in the digestive tract. Therefore, the present investigation describes approaches to rationally engineer the pH activity profiles of Aspergillus fumigatus and consensus phytases. Decreasing the negative surface charge of the A.

Structure-based chimeric enzymes as an alternative to directed enzyme evolution: phytase as a test case.

Thermostability is a key feature for commercially attractive variants of the fungal enzyme phytase. In an initial set of experiments, we restored ionic interactions and hydrogen bonds on the surface of Aspergillus terreus phytase, which are present in the homologous but more thermostable enzyme from A. niger.