Impact of EtBr on lactic acid fermentation

The impact of ethidium bromide on lactic acid fermentation by some lactic acid bacteria such as Lactobacillus gassesi MKR-23, Lactobacillus acidophilus MKR-37, Streptooccus thermophilus MKR-42, Lactobacillus lactis MKR-48 and Lactobacillus casei MKR-56 was assessed. It was found that the strain of Lactobacillus casei MKR-56 was much effective and good lactic acid producer. The compound ethidium bromide was found stimulatory when 18.00% (w/v) molasses solution was allowed to ferment at pH 6.2, temperature 37.00C and optimum incubation period of 6 days. It has been found that there is a gradual increase in the production of lactic acid with stepping up of the compound ethidium bromide till the maximum yield of lactic acid, i.e., 8.125 g/100 ml was obtained at its molar concentration of 6.0×1/10000×10M which is 12.847% higher in comparison to control fermentor flasks in 6 days of optimum incubation period.