Osmoadaptative accumulation of Nɛ-acetyl-β-lysine in green sulfur bacteria and Bacillus cereus CECT 148T.

The compatible solute N(ɛ)-acetyl-β-lysine (NeABL), thus far considered unique to methanogenic Archaea, has been found to accumulate in several strains of green sulfur bacteria (GSB) and Bacillus cereus CECT 148(T) under salt stress. A similar mixture of compatible solutes including trehalose, α-glutamate, β-glutamate and NeABL has been detected in salt-tolerant GSB strains of different phylogenetic branches. The ability of B. cereus to synthesize this compound was predicted from available genomic data, and nuclear magnetic resonance analyses of cultures grown in salt-containing media indicated that NeABL was present in the solute pools of osmotically challenged cells. The present results describe for the first time in the bacterial domain the use of this compound for osmoadaptation.