Verification of enzymes deterioration due to Cu(II) presence in an enhanced biological phosphorus removal system.
This study experimentally demonstrated that polyphosphate accumulating organisms (PAOs) losing the abilities of anaerobically synthesizing polyhydroxyalkanoates and aerobically taking up phosphate under Cu(II) presence was due to the inhibition of enzyme activities of acetyl-CoA synthases (ACS) and polyphosphate kinase (PPK), respectively. ACS activity tests showed the apparent maximum specific activity (Vmax) of ACS decreased with increasing Cu(II) concentration, revealing Cu(II) is a mixed inhibitor for ACS. Inhibition coefficients showed Cu(II) has a higher affinity for free ACS than for ACS-coenzyme A complex. PPK activity tests showed the Vmax substantially decreased with increasing Cu(II) concentration, revealing Cu(II) is also a mixed inhibitor for PPK. Inhibition coefficients showed Cu(II) more easily bound to free PPK than to PPK-Adenosine triphosphate complex. Experimental data also showed the aerobic mechanism of PAOs taking up phosphate was completely interrupted when 3mgL(-1) of Cu(II) was added.
Department of Civil Engineering, National Chi Nan University, Puli, Nantou 545, Taiwan. yptsai@ncnu.edu.tw
Yung-Pin
YP
Tsai
Huey-Fen
HF
Tzeng
Jan-Wei
JW
Lin
Meng-Shan
MS
Lu
Jyun-Yen
JY
Lin
D000105:Acetyl Coenzyme A / Q000378:metabolism*; D019149:Bioreactors; D003300:Copper / Q000633:toxicity*; D010758:Phosphorus / Q000378:metabolism*; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
D000105:Acetyl Coenzyme A; D003300:Copper; D010758:Phosphorus; D017856:Phosphotransferases (Phosphate Group Acceptor); D062065:Wastewater; D014874:Water Pollutants, Chemical; C022424:polyphosphate kinase