Time-course variation in the amount of BBP and the other chemical compounds produced during BBP degradation by esterase, as analyzed by GC/MS (BBP and the other chemical compounds formed in the BBP degradation by esterase were first extracted by n-hexane, and residual compounds in aqueous phase were dissolved in methanol after water was completely removed through lyophilization). ▾, IBF; ▴, DMP; ▪, BMP; ♦, BM; •, compound X.