Utilization of supplemented sugarcane molasses for continuous production of lactic acid by Lactobacillus curvatus

Abstract

Several by-products and raw-materials of food and agricultural industries have been used as culture medium. It is rich nutrients sources, and it is considered low cost and high availability of molasses as a substrate can be used in lactic fermentation. Lactic acid has tradicionally been obtained by chemical process, however, lactic acid production by fermentative process is considered most viable economically. Lactic acid has application in different industries such as pharmaceutical, cosmetic, textiles, leather, chemical and food industries, where about 82% of all world production is used. In this work, lactic acid production by L. curvatus under continuous culture on sugarcane molasses supplemented with yeast extract and peptone was evaluated. Dilution rates tested were 0,05; 0,10 and 0,15h-1 at 37ºC. Samples were taken for pH, reducing sugar, lactic acid, biomass and cellular viability measurements under steady state conditions. When the D was 0,05; 0,10 and 0,15h-1, the reducing sugar consumption was 7,1; 6,4 and 4,8g/L, respectively. Highest lactic acid production (13,8g/L) was obtained when D=0,05h-1 was used, while at D=0,10 and 0,15h-1, lactic acid production reached 10,2 and 7,1g/L, respectively. The highest values of biomass (1,98g/L) and cell viability (2,03x109CFU/mL) were reached at the lowest dilution rate tested (0,05h-1). In conclusion, the results showed that under tested conditions, low values of dilution rate were most suitable for continuous lactic acid production by L. curvatus in supplemented sugarcane molasses.