The cell lysate was loaded onto the columns at 1.5 mL/min, and the columns were washed with lysis buffer until the absorbance at 280 nm baselined. Elution was processed using a 100% gradient with elution buffer containing 500 mM NaCl, 50 mM imidazole pH 7.5, 1 mM EDTA, 3 mM DTT, and 10% glycerol. Eluted fractions exhibiting absorbance at 280 nm were collected and tested for phosphatase activity by addition of a few microliters of each fraction to a solution of pnitrophenylphosphate (pNPP), where an absorption increase at 400 nM indicated formation of pnitrophenol. Fractions that showed activity were assayed for purity on a 15% SDS-PAGE gel.