For the Acid Phosphatases activity assay, 50 μl of host cell containing supernatant was transferred to a new tube and let lyse on ice for 15 minutes. Protein concentration was measured with DC protein assay (Bio-Rad). The activity of acid phosphatases in 10 μg of the whole protein was analyzed according to the kit instructions (Acid Phosphatase Assay Kit CS0740, Sigma-Aldrich).   Absorption was measured with SpectraMax2 (Molecular devices) using SoftMax Pro v4.8 software.