Fed-Batch Bioproduction of Spectinomycin
13
for inoculating the seed culture. Direct inoculation from the slant is not recommended because only sporulating mycelia are good for spectinomycin
production.
3.2 Bioproduction Media
Satisfactory yields of spectinomycin are obtained from a variety of media
utilizing soybean meal as the principal nitrogen source. A typical media of the
following composition was satisfactory: soybean meal 20 g 1-1, cerelose 25 g 1 - 1
soybean oil 5 g 1-1, NaC1 5 g 1-1, CaCO3 1 g 1-1 and silicone antifoam 1 g 1-1
with pH unadjusted [23]. Another media formulation contains 0.5% phytone,
0.5% yeast extract, 1% glucose, 0.1% Bacto-Casetone, and 0.5% NaC1 [22].
However, media formulations used in industry employ cheaper ingredients
whose composition are optimized to give higher final titers of the antibiotic and
are a closely guarded secret. Some variations in the production media formulations include the utilization of cotton seed flour as the principal source of
nitrogen and amino acids. The other essential nutrients are obtained from
brewers yeast as well as from cotton seed flour. The initial pH in this case is
about 5.7 and is not adjusted before inoculation.
The carbon requirement is usually met with cerelose or a similar commercial
sugar source. In general, the seed culture formulation is not very different from
the final production medium recipe to ensure a minimum loss in time for
adaptation. Of course, the seed culture will almost always contain larger
amounts of the more easily metabolizable ingredients as compared to the
bioproduction medium. For laboratory scale spectinomycin production, the
seed culture medium contains twice the amount of carbon source as in production medium. This enables the microorganism to increase its cell mass rapidly in
the seed culture, while in plant production the amount is calculated such that
carbon source exhausts within 24 h when the idiophase or production phase sets
in. To maintain the productivity and to supply the maintenance energy during
the production phase continuous glucose feeding is necessary. Therefore, spectinomycin production is carried out in the fed-batch mode.
3.3 On-line and Off-line Analysis
On-line measurements are necessary in the implementation of effective process
control. Recent advances in the field of fiber optics and its application in
biosensors technology resulted in the development of miniature sensors for
glucose [29]. Although these glucose sensors are sensitive, selective and stable,
they are not durable enough for industrial bioprocesses. Only recently has the
development of an autoclavable glucose sensor been reported in the literature
[30]. A fluorescence based fiber optic biosensor for the flow injection analysis
(FIA) of penicillin reports excellent performance on pure samples [31]. Recently,
13
for inoculating the seed culture. Direct inoculation from the slant is not recommended because only sporulating mycelia are good for spectinomycin
production.
3.2 Bioproduction Media
Satisfactory yields of spectinomycin are obtained from a variety of media
utilizing soybean meal as the principal nitrogen source. A typical media of the
following composition was satisfactory: soybean meal 20 g 1-1, cerelose 25 g 1 - 1
soybean oil 5 g 1-1, NaC1 5 g 1-1, CaCO3 1 g 1-1 and silicone antifoam 1 g 1-1
with pH unadjusted [23]. Another media formulation contains 0.5% phytone,
0.5% yeast extract, 1% glucose, 0.1% Bacto-Casetone, and 0.5% NaC1 [22].
However, media formulations used in industry employ cheaper ingredients
whose composition are optimized to give higher final titers of the antibiotic and
are a closely guarded secret. Some variations in the production media formulations include the utilization of cotton seed flour as the principal source of
nitrogen and amino acids. The other essential nutrients are obtained from
brewers yeast as well as from cotton seed flour. The initial pH in this case is
about 5.7 and is not adjusted before inoculation.
The carbon requirement is usually met with cerelose or a similar commercial
sugar source. In general, the seed culture formulation is not very different from
the final production medium recipe to ensure a minimum loss in time for
adaptation. Of course, the seed culture will almost always contain larger
amounts of the more easily metabolizable ingredients as compared to the
bioproduction medium. For laboratory scale spectinomycin production, the
seed culture medium contains twice the amount of carbon source as in production medium. This enables the microorganism to increase its cell mass rapidly in
the seed culture, while in plant production the amount is calculated such that
carbon source exhausts within 24 h when the idiophase or production phase sets
in. To maintain the productivity and to supply the maintenance energy during
the production phase continuous glucose feeding is necessary. Therefore, spectinomycin production is carried out in the fed-batch mode.
3.3 On-line and Off-line Analysis
On-line measurements are necessary in the implementation of effective process
control. Recent advances in the field of fiber optics and its application in
biosensors technology resulted in the development of miniature sensors for
glucose [29]. Although these glucose sensors are sensitive, selective and stable,
they are not durable enough for industrial bioprocesses. Only recently has the
development of an autoclavable glucose sensor been reported in the literature
[30]. A fluorescence based fiber optic biosensor for the flow injection analysis
(FIA) of penicillin reports excellent performance on pure samples [31]. Recently,