EFFECTS OF INOCULATION OF A GENETICALLY-ENGINEERED BACTERIUM ON PERFORMANCE AND INDIGENOUS BACTERIA OF A SEQUENCING BATCH ACTIVATED-SLUDGE PROCESS TREATING PHENOL
S. Soda et al., EFFECTS OF INOCULATION OF A GENETICALLY-ENGINEERED BACTERIUM ON PERFORMANCE AND INDIGENOUS BACTERIA OF A SEQUENCING BATCH ACTIVATED-SLUDGE PROCESS TREATING PHENOL, Journal of fermentation and bioengineering, 86(1), 1998, pp. 90-96
A genetically engineered microorganism (GEM) Pseudomonas putida BH (pS
10-45), which was designed to exhibit higher phenol-degrading activity
than the wild strain, was inoculated into a model activated sludge pr
ocess to improve its phenol-treatment performance. The model activated
sludge process was operated as a 24-h-cycle sequencing batch reactor
in a shake bask, into which phenol-containing wastewater (500 mg/l) wa
s fed in the form of a shock loading three times at 7-d intervals and,
subsequently, semi-continuously (at 100-200 mg/l). After the shock lo
adings, the phenol-removal efficiency of the GEM-inoculated activated
sludge was much enhanced in comparison to that of a control process wi
thout GEM-inoculation for as long as the GEM population survived at a
relatively high level. During the semi-continuous feedings, the GEM-in
oculated activated sludge settled much better than that in the control
process, though phenol was completely removed in both processes. The
improvement in the settling properties was gradually lost as the GEM p
opulation declined. It was also observed that GEM-inoculation had a co
nsiderable effect on the behavior of the indigenous phenol-degrading b
acterial population, indicating that inoculation of the GEM delayed th
e occurrence of indigenous phenol-degraders. These results suggest tha
t GEM-inoculation can be a useful means of improving phenol-treating a
ctivated sludge processes.