Chapter 40 



Some Biochemical Differences Between 



Fresh Water and Salt Water Strains of 



Sulphate-reducing Bacteria 



F. W. OcHYNSKi and J. R. Postgate 



Xhe dissimilatory, sulphate-reducing bacteria are among the 

 commonest of microbes, being encountered in the majority of 

 marine and fresh water environments ( soil is included as a fresh 

 water environment). Their economic activities and some aspects 

 of their general physiology have been reviewed (15, 16) with 

 more extensive documentation than will be provided here. Their 

 ubiquity makes them a promising group for the study of the 

 biological and physiological characters that distinguish marine 

 from fresh water organisms because, at least in principle, one can 

 expect to be able to study the same species as it occurs naturally 

 in either environment, and one can further hope to observe the 

 acclimatization of strains from either environment to the other. 

 The present contribution records a few studies conceived from 

 this point of view. 



INTRODUCTION 



The taxonomy of the sulphate-reducing bacteria has been 

 the subject of some controversy in the literature; this has only 

 recently begun to be resolved. Beijerinck's (3) original species 

 Spirillum (now Desulfovibrio) desuljuricans was a fresh-water 

 type, and its isolation was followed by van Delden's (6) Micro- 

 spira (now Desulfovihrio) aestiiarii. Baars (2) and Kluyver & 

 Baars (9), referring to both types by the generic name Vibrio, 

 showed that the specific types were inter-convertible by training. 

 They did not favour the specific name aestuarii, Rittenberg (21) 

 and Zobell and Rittenberg (24) could not train their marine 

 strains to a fresh water habit. Littlewood & Postgate (11) ex- 



426 



