On novel halophilic and extremely halotolerant bacteria from environments near the North Sea coast and the Steinhuder Meer

Ecophysiological investigations on inner walls from two churches near the North Sea coast (Eilsum, Ostfriesland) and the inland lake Steinhuder Meer (Idensen, near Hannover) have shown that even in these environments hypersaline and highly alcaline conditions can occur. Thus the microorganisms occurring in such environments will have many relations with marine microorganisms. Halophilic and extremely halotolerant chemoorganotrophic bacteria have been isolated from these areas under conditions near the crystallization point of halite and at pH-values as high as pH 9.0. Some of these isolates are growing only under elevated sodium chloride or sulfate levels. Many of the isolates need salt concentrations highly above those of normal marine bacteria. They also adapt their internal and external (exudates) fatty acid patterns and metabolism to the changing salinities caused by brine seeping and evaporative forces. Many of the investigated bacteria are coccoid or coryneform. In many cases they considerably interfere with the mineral compounds of their immediate environment. In this way, they drastically change their own microenvironment as well as the character of the mineralogy. The typical pattern of fatty acids and compatible solute production under changing salinities are presently under investigation