The relationship between degradation rate of WVO,
bacterial growth and incubation time is an important
consideration when evaluating the efficacy of oil degrading
process. As shown in Fig. 5, the cell density was relatively
low on the first day then increased markedly from the
second day to the third day. In the following three days
cell density remains relatively constant and decreased in the
fourth day. The degradation rate was only a few percent on
the first day, and increased linearly in the next days. The
growth curve indicated that the bacteria were in the
adaptation phase on the first day when bacteria could not
grow and reproduce immediately. The bacteria would take a
period of time to grow in the new culture medium. The
second day and the third day was the logarithmic growth
phase, when bacterial metabolism was dynamic and synthesis
of new cellular material was fast. Bacteria entered into the
stationary phase from the fourth day.