Bulletin Spring‧Summer 2001

Figure 3 Methyl red decoloured (degraded) by Klebsiella pneumonia RS-13 Figure 4 Degradation of methyl red by Klebsiella pneumonia RS-13 T h e n he isolated another b a c t e r i um, Klebsiella pneumonia RS-13 ( F i g u re 3) , f r om the sludge samples, and discovered that t h i s b a c t e r i um c o u l d d e c o l o u r M R aerobically through reductive cleavage o f the dye i n t o am i n o b e n z o ic a c id a nd N,N' - d i me t h y l - p - p h e n y l e ne d i am i ne ( D M P D , Figure 4), a toxic aromatic amine. Moreover, the bacterium could metabolize D M P D into n o n - t o x i c c o m p o u n d s. P r o f . Wo n g 's experiments showed also that this bacterium c ou ld degrade othe r azo dyes such as PR , p r o c i on red H - E 3 B and p r o c i on yellow H - E4R. Besides bacteria, Prof. Wo n g isolated a fungus called Geotrichum canclidum CU - 1 ( F i g u re 5) whose extracellula r o x i d a t i ve enzymes could degrade PR and M R in only 12 to 24 hours 一 mu ch mo r e quickl y than Klebsiella pneumonia RS-13. Research to Continue Du r i ng his six years on the project, Prof. Wo n g f o u n d several possible s o l u t i o n s without encountering too much technical difficulty. His only regret is that the azo dye samples i n the p r o j e ct were n o t comprehensive enough and hence the findings could not be applied o n a large scale i n the d y e i ng i n d u s t r y . He w i l l continue to study other biosorption and biodegradation method s o f azo dyes so as t o d e s i g n t h e m o s t e f f e c t i v e i n t e g r a t i v e t r e a t m e nt s y s t em f o r i n d u s t r i al e f f l u e n t s a n d t o p r e v e n t environmental pollution . Prof. Wong Po-keung obtained his B. Sc. and M.Phil, from The Chinese University in 1977 and 1979 respectively, and his Ph.D. from the University of California in 1983. He joined CUHK as lecturer in biology in 1986 and was promoted to senior lecturer rank in 1994. Prof. Wong's research interest is in environmental biotechnology and environmental toxicology. He is concurrently associate director of the University's Centre for Environmental Studies. Figure 5 Decoiourization (degradation) of procion red MX- 5B by Geotrichum candidum CU-1 Complete medium Procion red MX-5B Incubation time: 6 days Save the Brooks, Rivers, and the Seas