Existence of different pools of fatty acids in anaerobic model ecosystems and their availability to microbial metabolism

Abstract Examination of the culture fluid from model anaerobic communities in multiple-vessel chemostats showed that the most abundant organic intermediate products of substrate breakdown, acetate and propionate, existed in 3 distinct pools. Radiotracers, [¹⁴C]acetate or [¹⁴C]propionate, equilibrated between a free pool which was extracted by ether, an adsorbed or complexed pool which was only partly extracted by ether, and a third small pool which was not extracted. A microbiological assay demonstrated that the free pool was available to metabolism by bacteria, the second pool was slowly metabolised, but the third unextractable pool was refractile and not available to metabolism. These results were compared to the situation in the sediment environment.