Production, purification, and characterization of CGA hydrolase from A. niger D15-ChlE16. (A1) Extracellular production of the protein in strain D15-ChlE16 over time. CGA activity (▴) and mycelial dry weight (•) are shown. (A2) SDS-PAGE analysis of the culture medium (lane 1), the purified protein (lane 2), and the deglycosylated protein (lane 3) with approximately 20 μg of loaded proteins. Proteins were stained with Coomassie blue. (A3) Purification of CGA hydrolase. Effects of temperature (B1) and pH (B2) on the activity of the purified protein. Various temperatures (37°C to 75°C) and pH values (3.85 to 8.55) were tested under standard conditions. The pH tests used a 100 mM citrate-phosphate buffer for activity assay. Effects of temperature (B3) and pH (B4) on the stability of the purified protein. The selected temperatures were 37°C (⧫), 45°C (▪), 50°C (▴), 60°C (+), and 65°C (•), and the selected pH values were 3.80 (⧫), 4.75 (+), 6.85 (▪), 7.85 (•), and 8.50 (▴). All assays were performed with CGA as the substrate. IMAC, immobilized metal affinity chromatography.