MICROBIAL METABOLISM AND ITS INDUSTRIAL IMPLICATIONS 



dealing with the more common organic materials would do well to 

 keep a constant careful watch for objectionable manifestations of mi- 

 crobial life in their factories. I could imagine that some of my hearers 

 would heave sighs of relief because their industrial products do not 

 belong to this vulnerable class, so that they can go on living in a bliss- 

 ful ignorance of what is going on in the microbe world. However, I 

 feel it my duty to disturb this illusion also by putting forward the 

 thesis that only very few industrialists will escape encounters with the 

 invisible life. These may be 'brief encounters', but we all know that 

 these too may have dire consequences. A few examples may suffice. 



I mentioned the vulnerability of wood as a construction material, 

 and it seems easy, at first, to avoid the use of this material by having 

 recourse to materials like stone or concrete. But investigations of Payne 

 and co-workers have made it highly probable that the stone walls of 

 many historic buildings in England, as for instance those of West- 

 minster Hall, are subject to microbial attack ; according to the well- 

 known Russian microbiologist Issatschenko even concrete structures 

 in contact with water may well be corroded by the growth of a special 

 acid-producing microflora at the surface. 



The important work done here in London during the war by Smith 

 and his co-workers is well known. This aimed to combat the deteriora- 

 tion of military equipment in a tropical climate. For the manufac- 

 turers of leather belts, and especially for those of optical instruments 

 and radio sets, it must have been a revelation to find that they had to 

 take into account the results of microbiological research. 



One might think that at least the heavy industry would be in the 

 happy situation of being able to ignore microbial life, but this hope, 

 too, should be abandoned. For the mineral oil industry ZoBell has in 

 recent years collected ample evidence that, under conditions some- 

 times realized in industry, hydrocarbons can also fall a prey to mi- 

 crobes. He mentions a case in which a pronounced decrease in the 

 octane rating of aviation spirit stored over water was due to bacteria 

 accumulating in the water phase and preferentially attacking the 

 branched chain hydrocarbons in the spirit. 



A somewhat analogous case is the following. A machine tool factory 

 seems to be an ideal place to escape interference from micro-organ- 

 isms. But an investigation made by Lee and Chandler has shown that 

 the oil- water emulsions used as lubricants and cooling agents in the 



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