Heterotrophic bacteria from an extremely phosphate‐poor lake have conditionally reduced phosphorus demand and utilize diverse sources of phosphorus

Abstract

Summary Heterotrophic P roteobacteria and A ctinobacteria were isolated from L ake M atano, I ndonesia, a stratified, ferruginous (iron‐rich), ultra‐oligotrophic lake with phosphate concentrations below 50 nM. Here, we describe the growth of eight strains of heterotrophic bacteria on a variety of soluble and insoluble sources of phosphorus. When transferred to medium without added phosphorus ( P ), the isolates grow slowly, their RNA content falls to as low as 1% of cellular dry weight, and 86–100% of the membrane lipids are replaced with amino‐ or glycolipids. Similar changes in lipid composition have been observed in marine photoautotrophs and soil heterotrophs, and similar flexibility in phosphorus sources has been demonstrated in marine and soil‐dwelling heterotrophs. Our results demonstrate that heterotrophs isolated from this unusual environment alter their macromolecular composition, which allows the organisms to grow efficiently even in their extremely phosphorus‐limited environment.

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