Studies on glycolic acid metabolism by freshwater bacteria1

Measurements of uptake and mineralization of 14 C‐labeled glycolic acid by freshwater heterotrophs showed that respiration (mineralization) accounts for 69% of total uptake, and that the heterotrophic potential (V max ) for glycolate is comparable with that for other commonly used substrates. Bacteria cultured from lake water showed uptake and mineralization patterns similar to those from the natural plankton. Enrichment of lake water with glycolic acid resulted in measured disappearance of the glycolic acid, in agreement with rates predicted by uptake kinetics, but bacterial response was slow and independent of added glycolate concentration. Under natural conditions the heterotrophic bacteria prevent glycolate from accumulating by mineralizing most of it to CO 2 soon after it is released by algae.