Volume 4, Number 1, p. 17-21
M. Shamtsyan1, E. Afrikian 2 and G. Antranikian 3
1 St. Petersburg State Institute of Technology (Technical University). Moskovsky Prospect 26, 198013 St Petersburg, Russia
Lactic acid batch and fed-batch fermentation directly from starch-containing substrates
Lactic acid and calcium lactate were produced by batch fermentation directly from noncooked starchy materials (rice bran, low grade wheat flour, potato tubers and sorghum grains) by using Streptococcus bovis, a rumen bacterium capable of digesting raw starch. The substrates were suspended in a dilute solution of sulphuric acid (pH about 1.5–2) and after allowing the mixture to stand for several hours, calcium carbonate was added to neutralize the acid and cause carbon dioxide to evolve, followed by inoculation of the bacterium. Of interest was the fact that the addition of a small amount of glucoamylase to the fermentation mixture resulted in significant acceleration of the fermentation. Fed-batch fermentation were performed using corn starch as a substrate. A practical method of lactic acid production by fermentation methods has been demonstrated.