IDENTIFICATION AND CHARACTERIZATION OF S-LAYER PROTEINS IN AROMONAS HYDROPHILA AND LACTOBACILLUS ACIDOPHILUS

Lyophilization of Aromonas hydrophila and Lactobacillus acidophilus destabilized the H-bonds involved in binding of surface layer protein (Slayer) to the cell wall, glycerol but not water protected the bonds and prevented the loss of this layer. S-layer was extracted and purified by gel filtration on Sephadex G-100, only a single band was observed on polyacrylamide gel electrophoresis under non denaturing conditions. The molecular weight of the purified protein were estimated by Sodium dodecyle sulfate polyacrylamide gel electrophoresis, it was about 52000 dalton for A. Hydrophila and 43000 dalton for L. acidophilus. The transmission electron microscopy (TEM) showed that the glycerol protected this layer but not water.