Evaluation of Hybrid Short Path Evaporation to Concentrate Lactic Acid and Sugars from Fermentation

Lactic acid is an important organic compound that finds various applications in the chemical, pharmaceutical, food, and medical industries. Many of these applications require lactic acid with high purity. Hybrid short path evaporation (HSPE) is a separation process well studied in the petrochemical sector that is mainly used to obtain compounds with high purity. It is also a process offering small residence time, low pressure, and environmentally friendliness. The concentration process of lactic acid was studied by using HSPE in the presence of high total reducing sugar content remaining from sugarcane molasses fermentation. In this work, the influence of operational conditions, such as evaporator temperature (86.4 degrees C to 153.6 degrees C), internal condenser temperature (7.95 degrees C to 18 degrees C), and feed flow rate (8.27 to 21.7 mL/min), on lactic acid concentration and mass percentages were evaluated. The results showed that all variables influenced the process. Mathematical models were developed for the mass percentage and concentration of the total reducing sugar in the distilled stream and for the mass percentage at residue stream. Under the best operational conditions, the concentration of lactic acid (approximate to 247.7 g/L) was 2.5 times higher than the initial fermentation broth (approximate to 100.1 g/L).