A new beta-propeller phytase with optimal activity at low temperature produced by marine microorganism

Abstract

The aim of this study was to isolate phytase, which shows high activity at low temperatures. For this purpose, marine microorganism, producing phytase with high activity at low incubation temperature, was isolated from foreshore soil. The results of 16s rRNA sequence analysis showed that selected marine microorganism was similar to Pseudomonas sp. The phytase gene from the isolated Pseudomonas sp. was cloned and sequenced. Sequence analysis showed a 1,863 bp fragment encoding 620 amino acid residues. The molecular weight was found to be about 70 kDa by SDS-PAGE. Molecular modeling predictions with the obtained amino acid sequence seemed to belong to the group of beta-propeller phytase (BPP). The characterization of recombinant BPP from Pseudomonas sp. (PSphy) showed a highest activity at pH 6 and 40°C. However, our study found that 80% of optimal activity was shown even at the relatively low temperature of 25°C. In addition, CaCl2 was required to show activity and the optimal concentration of CaCl2 was 4 mM. The PSphy activity was maintained at 60 g/l of salt concentration and it was confirmed that the catalytic efficiency was 0.024 μM-1∙s-1 in the optimal conditions. Based on these characteristics, found in this study, it can be suggested that PSphy is a candidate for feed additives in the aquaculture industry and can be used to study low temperature activation mechanisms.