13-08-2012, 02:24 PM
Enhancement in production of erythromycin by Saccharopolyspora
erythraea by the use of suitable industrial seeding-media
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ABSTRACT
Background and purpose of the study: There is no report on the effect of seeding-medium
ingredients on Saccharopolyspora erythraea growth and erythromycin production. In this
study, the enhancing effects of seeding-media which have been used routinely for
screening, isolation or identification of actinomycetes, on Saccharopolyspora erythraea
growth and erythromycin production were investigated.
Methods: The control medium contained soybean meal, glucose, glycerol, (NH4)2SO4 and
CaCO3 as the major constituents and several media (I, II, III, ISP2, ISP3 and ISP4) were
used for production of the antibiotic. Concentrations of biomass and erythromycin were
measured by spectrophotometry, HPLC and bioassay methods and the effects of the
composition of seeding media on pH were also determined.
Results: The concentration of erythromycin in medium II was 2.71g/l (1.33 times more than
that of the control medium) and trends in production were: medium II > ISP4 = ISP2 =
Control > ISP2 = Control = ISP3 > ISP3 = medium III = medium I. In the media containing
starch and casein, the hyphae of S. erythraea were star-shaped and much branched.
Major conclusion: By virtue of other technical and economical characteristics of the
seeding media used for erythromycin production, it is concluded that medium II is the best
seeding medium formulation for erythromycin in comparison to others.
INTRODUCTION
Actinomycetes are Gram-positive soil bacteria
that produce a wide variety of antibiotics and
other secondary metabolites (1). In general, the
productivity of microbial metabolites is closely
related to the method of fermentation.
Physiological and genetic characteristics of the
strain, the medium composition, changes in
nutrients and their concentrations have various
effects on the accumulation of different
metabolites. The carbon and nitrogen sources may
dramatically influence antibiotic formation (2,3).
While there are several reports on the effect of
fermentation-media ingredients (4-7) and
environmental conditions (8,9) on erythromycin
production, there is no report on the effect of
seeding-media ingredients on the strain growth
and antibiotic production. In this investigation,
impacts of various seeding media on the growth
of Saccahropolyspora erythraea and
erythromycin production were studied.
Determination of the erythromycin
Assay of total erythromycin
The concentration of total erythromycin, after
removal of the biomass, residual oil and insoluble
ingredients by centrifugation was measured by
modified colorimeteric method (13). It is important
to remove residual oil from fermentation broth,
since it interferes with determination of
erythromycin by colorimetric method. Aqueous
fraction of the fermentation broth was diluted with
0.2 M carbonate/bicarbonate buffer, of pH 9.6,
and extracted with chloroform. Extracted
erythromycin was mixed with the bromophenol
blue reagent (0.008% bromophenol blue in 0.2 M
citrate–phosphate buffer, pH 4.2). The absorbance
of the organic layer which was separated with
great care was measured at 415 nm by a
spectrophotometer.
DISCUSSION
Optimization of fermentation conditions is
necessary to improve secondary metabolites
formation. In this research, effects of seedingmedia
ingredients on the growth of
Saccharopolyspora erythraea and erythromycin
production were evaluated. In medium II
(containing starch and casein as the main
substrates), production of erythromycin was
maximum. Medium II has been used for screening
and isolation of actinomyceytes (16). ISP media
are the traditional media for cultural
characterization of actinomycetes (11). However,
there is no report on the use of these media for
seeding in production of erythromycin. On the
basis of technical and economical point of views
of the seeding media which were used for
production of erythromycin (Table 1), it may be
concluded medium II was the best seedingmedium
formulation for erythromycin in
comparison to the other reported media.