| description abstract | Lactic acid (LA) and probiotic biomass production were evaluated from bovine manure supported with 12% v/v molasses using three probiotic bacteria, Lactobacillus acidophilus, Lactobacillus fermentum, and Bacillus subtilis, with three inoculum concentrations, 5%, 10%, and 15% v/v. Laboratory-scale tests were carried out in 250-mL flasks (useful volume of 200 mL) at 37°C and 120 rpm for 72 h. During this time, samples were taken every 4 h to determine (1) the LA content using titration, (2) cell growth using the poured plate method, and (3) consumption of carbohydrates using the anthrone-sulfuric method. The data obtained were adjusted to the Gompertz generalized four-parameter model to obtain the kinetic parameters of the growth of the bacteria in the residue. With the species L. acidophilus at 10% v/v, the highest LA production yield was obtained, Y(P/S)=0.7 g LA/g carbohydrates, with a concentration of 13.5 g LA/L (p>0.05) and values of μmax=0.161/h and Ks=0.46 g/L. With the same bacteria at 15% v/v, the biomass obtained had the highest concentration of proteins, 32.19% dry weight of proteins (p>0.05). The results showed that bovine manure has the potential to produce LA and biomass, which are products with high nutritional, economic, and energetic value. | |
