Molasses processing methods effect on lactic acid synthesis by Enterococcus bacteria

The aim of the study was to determine the parameters for cost-effective production of lactic acid from secondary raw materials (beet molasses) using lactic acid bacteria of the species Enterococcus faecium and Enterococcus sp; to assess the feasibility of using current methods of molasses pre-treatment (using EDTA, Trilon B, JCS). As a result of the studies, the ability of Enterococcus bacterial strains to biosynthesize lactic acid (LA) was studied using nutrient media with different contents of beet molasses as a carbon source. Molasses is a by-product of the sugar industry. Bacteria of the species Enterococcus faecium and Enterococcus sp. were isolated from fermented wheat bran. Cultivation on pre-treated molasses was carried out for 72 h, fermentation on media with different concentrations of the carbon source - 48 h. The fermentation process was carried out in shaking flasks. The content of LA was determined using capillary electrophoresis. During fermentation of pre-treated molasses, the highest MC concentration in the culture fluid reached 16.8 g/l (E. faecium, 48 h from the start of fermantation, treatment with Trilon B). The MC concentration in experiments using untreated molasses reached 16.2 (E. faecium) and 16.4 g/l (E. sp). When culturing the studied strains on untreated molasses, the highest MC yield was obtained at a mass concentration of sugars in the medium of 75 g/l. The value of the indicator was practically at the same level and amounted to 14.20 g/l for E. faecium and 14.21 g/l for E. sp., and the degree of bioconversion was 18.93 and 18.95 %, respectively. The data obtained indicate that the fermantation of E. faecium and E. sp. Bacteria on untreated sugar beet molasses can be used as a cost-effective method for obtaining lactic acid and recycling secondary raw materials.