FIELD: chemistry.
SUBSTANCE: process for fermenting a CO-containing substrate is disclosed. Process comprises providing a CO-containing substrate to a fermenter, fermenting the CO-containing substrate with acetogenic bacteria cells to obtain a target cell density of about 3 g/l to about 30 g/l, and a target CO feed rate of 3.5 to 6 standard cubic feet per hour per litre, while maintaining the concentration of dissolved CO during fermentation ranging from 3.1 to 3.8, or from 2.2 to 3.2, or from 3.1 to 4.1 pounds per square inch. Concentration of dissolved CO is maintained by reducing the target CO feed rate for fermentation by about 25% to about 35% of the target CO feed rate, providing a first reduced CO feed rate and maintaining the first reduced CO feed rate for about 1 to about 10 minutes; subsequent increase in the first reduced CO feed rate for fermentation to provide a second reduced CO feed rate that is lower by about 15% to about 25% of the target CO feed rate, and maintaining a second reduced feed rate for about 1 to about 5 minutes; then raising the second reduced CO feed rate for fermentation to provide a third reduced CO feed rate that is lower by about 5% to about 15% of the target CO feed rate, and maintaining a third reduced feed rate for about 1 to about 5 minutes and increasing the third reduced CO feed rate to the target feed rate or higher.
EFFECT: method is effective to provide STY 10 g ethanol /(l⋅day) or more.
5 cl, 10 dwg, 2 tbl, 4 ex
