FIELD: biotechnology.
SUBSTANCE: method for fermentation of a CO-containing gaseous substrate is provided (options). The method includes feeding a CO-containing gaseous substrate to the fermentation medium with acetogenic bacteria and fermentation of the substrate. In one embodiment of the method, the ratio of the conductivity of the medium to the specific absorption of carbon according to the formula SCU=SCUmax-F*conductivity is maintained to control the conductivity of the fermentation medium. SCUmax is equal to maximum 3 and F is from 0 to 1. In the second embodiment the ratio of the medium (y) conductivity to the specific gas feed speed (x) according to the formula y=-6.0327x+12.901 before reaching the specified cell density is maintained, where x is from 0.2 to 0.7 mmol/min/gram of cells. The value of cell density and conductivity of the medium is maintained. In the third embodiment chloride ions are replaced with an ion in a fermentative medium. The ion is selected by the group consisting of hydroxide, acetate, carbonate, bicarbonate and their mixtures in the amount effective for reaching the conductivity value of the fermentative medium, which is 30 msec/cm or less.
EFFECT: increase in the yield of ethanol.
13 cl, 31 dwg, 3 tbl, 5 ex
