Microbiologia Industrial

industrial
micro-organisms
T he contribution of microbiology to the
a lleviation of disease and its possible role in helping to make up food
s hortages, especially in the developing countries,
w ere among the topics reviewed at a symposium on the use
of radiation and radioisotopes for the genetic improvement of industrial
m icro-organisms,
h eld at Agency Headquarters a few weeks ago.M icrobial fermentation industries have undergone revolutionary development in recent years — development which has led to the large-scale
p roduction of various organic substances having nutritional, medicinal or
o ther desirable characteristics. Some such uses of "industrial microorganisms" were discussed in an article in the Bulletin (Vol. 12, N o . 2)
l ast year.
T he 88 participants inthe symposium, from 28 countries, four international organizations and the IAEA, heard first an introductory survey
b y S. I. Alikhanian, of the Institute for Genetics and Selection of Industrial Micro-organisms, Moscow. Alikhanian pointed out that the combination in the programme of the symposium of questions relating to
g enetics, biochemistry and technology was not accidental. "The organizationof any industrial production based on microbial synthesis," he said,
" deals with two problems: die first concerns physiological and biochemical investigation. Microbiologists discover new forms of microorganism and together with biochemists find their new capacities to
s ynthesise specific products. Sometimes these may be well studied forms
of micro-organisms that reveal a capacity tosynthesise new substances,
as it is with penicillin and streptomycin. However most wild microorganisms appear to display weak synthesising capacity, hence organization of industrial production based on them is unprofitable.
" The second problem concerning organization of microbiological
p roduction is determined by selection of these strains, with the purpose
of obtaining a sharp increase in theproductivity of wild micro-organisms.
" Parallel with the isolation of new, highly-active strains there develop
w ide studies of the requirements of selectional strains for nutrient substances, screening of precursors, investigations of optimal aeration conditions, t emperature conditions for biosynthesis, methods of preparation
a nd growth on plating material and so on.
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" In all aspects ofthese studies directed to the increase of the productivity of micro-organisms genetics plays the most important role.
I t is quite obvious that success in the selection of micro-organisms
d epends on the application of genetic methods. Numerous attempts to
i gnore genetic methods in the selection of micro-organisms have always
l ed to failure."
A likhanian, who is recognised as a pioneer inthis work, pointed out
t hat genetic methods in combination with the use of ionizing radiation
( in particular, X-rays) played the greatest role in die first stage in the
d evelopment of techniques for the selection of micro-organisms. X-rays,
a v ery active mutagen, were first used 25 years ago by M. Demerec in
t he isolation of the first mutant strain oiPenicillium Chrysogenum, X -1612,
which was as much as three times as productive as the wild strain
1 951-B25. U se of such superactive strains enabled microbiological synthesis to become not only profitable for the production of a number of
c ompounds, but competitive with chemical synthesis.
T he use of ultra-violet light was the next mutagenic technique to be
d eveloped. P. chrysogenum w as again the first micro-organismtreated; the
m utant Q-176 was isolated, displaying activity which exceed that of the
o riginal strain by a large factor — and was three times that of the first
m utant induced by X-irradiation.
L ater, gamma-irradiation and fast neutrons were tested and used
s uccessfully. The effectiveness of fast neutrons markedly exceeded that
of X-rays and UV-light. Chemical mutagens were also used ;...