For this, isolated alkaliphilic bacteria were streaked onto blood agar plates containing (g l−1) trypticase 10, beef extract 3, NaCl 5 and agar 15. After autoclaving, 5% (v/v) sterile human blood was added (pH 10).Plates were incubated at 30 ◦C for 24 h and visually inspected for zone of clearance around the colony.