Metabolite analysis of Bacillus SE
Two antibacterial factors corresponding to autolysins and
AHL-lactonases were screened.
The percentage autolytic rate of the Bacillus SE strain
was evaluated at pH 6 (31.35 ± 2.1), 6.5 (61.72 ± 3.4)
and 8.5 (70.12 ± 2.7) in MES, phosphate, and Tris–HCl
buffers respectively, using exponential phase cells grown
in LB. The autolytic rates of peptidoglycan hydrolases of
Bacillus SE strain were increased with increase in pH. The
autolytic rate was measured after 72 h of incubation at
30C and no significant variation was observed after further incubation. In the enzyme assay of acetylglucosaminidase, the specific activity of SE supernatant was
2.4 mU mg protein-1. With regard to AHL-lactonases, the
PCR product of corresponding aiiA gene was amplified in
Bacillus SE strain as reported earlier (Lee et al. 2002) and
it confirmed the presence of AHL-hydrolysing lactamases
in Bacillus SE.