The biomass is not initially able to degrade some persistent
xenobiotic, but does so after a period of induction or biochemical
adjustment, known as acclimation (Singleton, 1994; Buitron and
Gonzalez, 1996; Mangat and Elefsiniotis, 1999). In order to adapt
the bacteria to the sewage gradually and improve the biodegradation ability of the bacteria, the sewage was added into the medium
at different time periods until the whole medium was sewage just
as done inTable 1. However, not all microbial cells become degrader during and after acclimation (Chong and Lin, 2007). So the
number of the bacteria must be guaranteed by acclimation or
domestication period