Effects of carbon and organic nitrogen sources on cell
growth and cellulose production in shaking flasks It
was found from preliminary experiments that yeast
extract (YE) stimulated cellulose production. First, we
examined the effects of YE concentrations on cell growth
and cellulose production in different carbon media. The
YE was added to HS media in the range from 0.5 to
6%, while carbon sources comprised 2%. The overall
growth pattern and the specific growth rate corresponding
each carbon source of strain BRCS were not significantly
affected by the initial YE concentrations, but
growth phases were extended with increasing YE concentration
as shown in Fig. 2. This resulted in increased
final cell concentrations. Polysaccharides were produced normally with a substantial surplus of carbon source
present in the medium under conditions limited by
nutrients such as the nitrogen or phosphorous. As gluconic
acid was not produced during cultivation in fructose
and sucrose media, growth curves corresponding to
these substrates were different from that of glucose. The
amounts of cellulose produced from different carbon
sources are compared in Fig. 3. Of the substrates tested,
the highest cellulose yields were obtained in the fructose
medium, and the culture containing 4% YE yielded the
maximum value of 3.7 g/l. Cellulose production in sucrose
medium was much lower than that in fructose
medium even though the cell yield in sucrose medium
was slightly higher than that in fructose medium.
Effects of carbon and organic nitrogen sources on cellgrowth and cellulose production in shaking flasks Itwas found from preliminary experiments that yeastextract (YE) stimulated cellulose production. First, weexamined the effects of YE concentrations on cell growthand cellulose production in different carbon media. TheYE was added to HS media in the range from 0.5 to6%, while carbon sources comprised 2%. The overallgrowth pattern and the specific growth rate correspondingeach carbon source of strain BRCS were not significantlyaffected by the initial YE concentrations, butgrowth phases were extended with increasing YE concentrationas shown in Fig. 2. This resulted in increasedfinal cell concentrations. Polysaccharides were produced normally with a substantial surplus of carbon sourcepresent in the medium under conditions limited bynutrients such as the nitrogen or phosphorous. As gluconicacid was not produced during cultivation in fructoseand sucrose media, growth curves corresponding tothese substrates were different from that of glucose. Theamounts of cellulose produced from different carbonsources are compared in Fig. 3. Of the substrates tested,the highest cellulose yields were obtained in the fructosemedium, and the culture containing 4% YE yielded themaximum value of 3.7 g/l. Cellulose production in sucrosemedium was much lower than that in fructosemedium even though the cell yield in sucrose mediumwas slightly higher than that in fructose medium.
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