Van Niel E W, Appeldoorn K J, Zehnder A J, Kortstee G J
Department of Applied Microbiology, Lund University, S-22100 Lund, Sweden.
Appl Environ Microbiol. 1998 Aug;64(8):2925-30. doi: 10.1128/AEM.64.8.2925-2930.1998.
Activated sludge not containing significant numbers of denitrifying, polyphosphate [poly(P)]-accumulating bacteria was grown in a fill-and-draw system and exposed to alternating anaerobic and aerobic periods. During the aerobic period, poly(P) accumulated up to 100 mg of P x g of (dry) weight. When portions of the sludge were incubated anaerobically in the presence of acetate, 80 to 90% of the intracellular poly(P) was degraded and released as orthophosphate. Degradation of poly(P) was mainly catalyzed by the concerted action of polyphosphate:AMP phosphotransferase and adenylate kinase, resulting in ATP formation. In the presence of 0.3 mM nitric oxide (NO) in the liquid-phase release of phosphate, uptake of acetate, formation of poly-beta-hydroxybutyrate, utilization of glycogen, and formation of ATP were severely inhibited or completely abolished. In cell extracts of the sludge, adenylate kinase activity was completely inhibited by 0.15 mM NO. The nature of this inhibition was probably noncompetitive, similar to that with hog adenylate kinase. Activated sludge polyphosphate glucokinase was also completely inhibited by 0.15 mM NO. It is concluded that the inhibitory effect of NO on acetate-mediated phosphate release by the sludge used in this study is due to the inhibition of adenylate kinase in the phosphate-releasing organisms. The inhibitory effect of nitrate and nitrite on phosphate release is probably due to their conversion to NO. The lack of any inhibitory effect of NO on adenylate kinase of the poly(P)-accumulating Acinetobacter johnsonii 210A suggests that this type of organism is not involved in the enhanced biological phosphate removal by the sludges used.
不含大量反硝化聚磷菌的活性污泥在间歇式进水系统中培养，并经历交替的厌氧和好氧阶段。在好氧阶段，聚磷积累至每克（干）重含100毫克磷。当部分污泥在乙酸盐存在下进行厌氧培养时，80%至90%的细胞内聚磷被降解并以正磷酸盐形式释放。聚磷的降解主要由聚磷酸：AMP磷酸转移酶和腺苷酸激酶的协同作用催化，导致ATP形成。在液相中存在0.3 mM一氧化氮（NO）时，磷酸盐的释放、乙酸盐的摄取、聚-β-羟基丁酸酯的形成、糖原的利用以及ATP的形成均受到严重抑制或完全消除。在污泥的细胞提取物中，0.15 mM NO完全抑制了腺苷酸激酶的活性。这种抑制的性质可能是非竞争性的，类似于对猪腺苷酸激酶的抑制。活性污泥聚磷酸葡萄糖激酶也被0.15 mM NO完全抑制。得出的结论是，本研究中使用的污泥中，NO对乙酸盐介导的磷酸盐释放的抑制作用是由于对释放磷酸盐的生物体中腺苷酸激酶的抑制。硝酸盐和亚硝酸盐对磷酸盐释放的抑制作用可能是由于它们转化为NO。NO对聚磷积累菌约翰逊不动杆菌2l0A的腺苷酸激酶没有任何抑制作用，这表明这类生物体不参与所用污泥增强生物除磷的过程。
