The source of reducing power in the anaerobic metabolism of polyphosphate accumulating organisms (PAOs) – a mini-review

摘要

Glycolysis has been generally accepted to be the source of reducing power used for the synthesisnof polyhydroxyalkanoates (PHAs) in the anaerobic metabolism of polyphosphate accumulatingnorganisms (PAOs). However, the tricarboxylic acid cycle (TCA) has also been suggested toncontribute to the generation of reducing equivalents, creating some controversy in this researchnfield over the last two decades. Various research approaches have been applied in order tonclarify this issue, including the analysis of intracellular compounds, labelled carbon substratesnand gene expression. However, the conclusions of these studies seem not to be consolidated.nThe extent of TCA cycle involvement could be related to the experimental methods employed,nthe community structure of the cultures used, and also the operational conditions employed.nThis mini-review analyses the historical findings related to the source of reducing power in PAOs,nand highlights the different approaches used in the previous studies. Key factors influencing thengeneration of reducing power through different metabolic pathways are discussed, and furthernresearch directions are also proposed.