Glycolate metabolism by Pseudomonas sp., strain S227, isolated from a coastal marine sediment

Glycolate excreted by phytoplankton is a potentially important nutrient for bacteria in coastal and estuarine environments. The metabolism of glycolate by Pseudomonas sp., strain S227, originally isolated from the New York Bight Apex, has been studied. The specific growth rate for this strain on glycolate is 0.156 doublings h^-1. The apparent V_max and K_m for glycolate uptake are 83.6 nmol min^-1 mg cell protein^-1 and 7.4x10^-8 M, respectively. The preferential respiration of the carboxyl carbon (C-1) and the incroporation of the hydroxymethyl carbon (C-2) suggest that the glycerate pathway is used for growth on glycolate. Alternatively, another pathway can be utilized which results in the complete catabolism of glycolate. Glycolate and lactate metabolism are also closely linked either by a common metabolic pathway or a common transport system other than the monocarboxylate transport system. The magnesium ion concentration is also important in glycolate metabolism. The characteristics of glycolate metabolism observed in Pseudomonas sp., strain S227, are advantageous in coastal and estuarine environments where glycolate production is intermittent, and the concentrations are low.