During the SA test, the bacterial culture was incubated and spun at a 5500 rpm rotation rate for 24 hours at 4 °C. The obtained pellet was washed (twice) and resuspended in 0.002 M sodium phosphate buffer having pH 6.8. A 4 M solution of ammonium sulphate [(NH4)2SO4] was diluted using sodium phosphate buffer solution according to the scheme given in table .