LACTIC ACID PRODUCTION BY BACTERIA ISOLATED FROM RHIZOSPHERIC SOIL OF DAHLIA TUBERS

We isolated lactic acid bacteria from the rhizospheric soil of dahlia tubers. Lactic acid was produced by batch fermentation of dahlia hydrolysate. The selection of the best homolactic acid productive strain was made by biotechnological characteristics: pH tolerance, lactic acid yield and lactic acid productivity. The selected strains produced lactic acid at maximum yield after 48 hours of fermentation. The productivity was better after 48 hours of fermentation. For all investigated strains, the Lbd2 strain showed the best lactic acid production yield of 6.30 ± 0.02 after 96 hours of fermentation and was the most acid-tolerant bacteria, due to the pH value which was 3.3±0.06. The Lbd2 lactic acid productivity after 48 hours of fermentation was 0.10 g· L -1 · h -1 , being the highest value obtained of all the strains studied.