Novel biocatalytic strategy of levan: His-ELP-intein-tagged protein purification and biomimetic mineralization.

Here a versatile fusion tag composed of His-tag, intein, and elastin-like polypeptide (ELP) tag was prepared for the first time to be fused with levansucrase SacB to construct a recombinant His-ELP-intein-SacB (HEIS) protein to realize nonchromatographic purification of SacB. The efficient biomimetic mineralization of CaHPO and HEIS-based hybrid-hydrangea (CaHPO-HEIS-HH) with good reusability, excellent storage stability and 254.3% improved relative levan yield was prepared with the biomimetic mineralization method. Additionally, the CaHPO-HEIS-HH showed outstanding operation activity when catalyzing sucrose in solution and up to 75% sucrose conversion rate in fruit juices. The mechanism of biomimetic mineralization was analyzed to show that the HEIS protein might serve as a "binder" to assemble the nanoflakes during biomimetic mineralization. The CaHPO-HEIS-HH was applicable for efficient production of the levan-type prebiotic polysaccharides, and this approach should be highly valuable for nonchromatographic purification and convenient preparation of various encapsulated enzymes for more efficient catalysis.