Bacterial cellulose production under oxygen-enriched air at different fructose concentrations in a 50-liter, internal-loop airlift reactor

Bacterial cellulose (BC) production by Aceto-bacter xylinum subsp. sucrofermentans BPR2001 was carried out in a 50-1 internal-loop airlift reactor in air at an initial fructose concentration of 40 g/l. The BC production rate was 0.059 g/l per h. When oxygen-enriched air was supplied instead of air the BC production rate increased to 0.093 g/l per h, and the BC yield was enhanced from 11% in air to 18%. When the initial fructose concentrations were varied from 30 to 70 g/l, the highest BC yield (35%) the highest production rate (0.22 g/l per h), and the highest concentration of BC produced (10.3 g/l) were observed at 60-70 g/l fructose. From the carbon mass balance calculated at the final stage of cultivation, it was observed that enhanced BC production was reflected as a decrease in both CO2 evolution and the concentration of other unknown substances, suggesting the efficient utilization of energy for BC synthesis despite O-2 limitation.