[From biotechnology to bacterial toxins and immunomodulators].

The disposal of industrial wastes has been recognized as a serious problem long before the ecological movement gained its present strength. The possibility of using "useful" bacteria for this purpose was considered rather early and numerous studies were made to use them for the biological treatment of industrial wastes. Such attempts have taken advantage of the development of large scale fermentors for the production of bacteria while at the same time they have stimulated progress in the technology of fermentors. The advances made in the technology of fermentors have also made possible the large scale production of pathogenic bacteria. This has made possible the production of bacterial toxins in adequate amounts, enabling investigators to purify them to homogeneity, to characterize the purified toxins physico-chemically and immunologically and to study their structure-function relationships. Similarly, large quantities of bacteria exhibiting specific biological activities could be produced and the constituents responsible for the activities of these bacteria could be isolated and characterized. In this paper, the Author describes the stages of his progress and processes through the fields of the biotechnology and toxinology to that of immunomodulators. His investigations have largely taken advantage of developments in the technology of fermentors. "Ecologic" bacteria have been isolated which are capable of using phenol as the only source of carbon or cyanides as the sole source of carbon and nitrogen. These bacteria have been used for the treatment of industrial wastes enriched either with phenol or with cyanides. Another type of "useful" bacteria investigated was Bifidibacterium bifidus which has a fundamental role in the economy of the breast-fed infant. B. bifidus is present only in the gut of infants fed with mothers-milk. Growth factors for B. bifidus have been isolated from casein hydrolyzates which permitted the implantation of B. bifidus in the gut of infants fed with cows-milk supplemented with these factors. A further development of this type of research has been the large scale production of toxigenic bacteria. As a result large quantities of tetanus toxin have been produced and a method of purification has been devised. The availability of large amounts of purified tetanus toxin made it possible to determine the physico-chemical characteristics of the toxin as well as some of its structure-function relationships. In addition, the mechanism of detoxification of protein toxins by the action of formaldehyde has been clarified. Enzymatically derived toxin fragments have also been purified.(ABSTRACT TRUNCATED AT 400 WORDS)