FIELD: biotechnology.
SUBSTANCE: method includes acetogenic bacteria culturing on the first substrate to obtain cell density of at least about 0.005 g/l. The first substrate includes a carbon source selected from the group consisting of a yeast extract, carbohydrates, alcohol, amino acids, peptone, peptides, protein, fatty acids, lipids and mixtures thereof. The acetogenic bacteria are sporulated by replacing at least a portion of the first substrate with a synthesis gas containing at least 10 mol % of CO, and replacing at least a portion of the first substance with a production medium to convert at least a portion of the bacteria to spores with further spore germination in a production medium at a pH of about 4.1-5 using a synthesis gas containing at least about 10 % mol of CO. At that, sporulation provides a ratio of spores to cells at least about 0.05. The invention provides specific absorption of CO at least about 0.25 mM/min/gram of cells and productivity (STY) of about 1 g or more of ethanol/(l per day per gram of cells).
EFFECT: increaseed biomass yield.
5 cl, 7 dwg, 1 tbl, 8 ex
