Effects of Zinc Stress on the Bacterial Population Structure of Activated Sludge as Determined by Lipoquinone Profiling.

The quinone profiling technique was used to investigate the effects of zinc stress on the bacterial population structure of sewage activated sludge in laboratory-scale reactors. The quinone composition of sludges cultivated under different conditions with respect to the sludge retention time and zinc concentrations was determined by thin-layer chromatography, ultraviolet spectroscopy, reverse-phase high-performance liquid chromatography, and mass spectrometry. Numerical analysis of the quinone profiles showed that there were significant differences in the community structure between sludges cultivated with Zn2+ and without Zn2+. When the sludge was loaded with Zn2+, the sludge retention time was also an important factor affecting the quinone composition. The changes in the quinone composition from the normal sludge to the zin-stressed sludges resulted mainly from an increase in bacterial populations with ubiquinone-8 and a decrease in those with partially hydrogenated menaquinones.