The cell pellet was re-suspended in 1 mL of PBS pH 7.0 with: (i) bile extract
(0.3% w/v), or (ii) a-amylase (100 U mL1) or (iii) pancreatin (0.2% w/v; a mixture of digestive enzyme secreted by the pancreas and commonly used to simulate the pancreatic juice present in the intestinal digestion), or (iv) 1 mL of saline solution adjusting the pH with HCl 0.1 M (0.85% w/v; pH 2.5) for low pH studies.