Chemical reaction as a method for the separation of biologically-derived carboxylic acids

The biotechnological production of organic compounds using renewable carbon sources is an approach consistent with sustainable development and green technologies. The development of these processes requires refinement of both the upstream stage, including the selection of microorganisms and the use of waste raw materials, and the downstream stage. The fermentation broth contains not only the main product but also unreacted substrates and by-products. The paper presents computer simulations that analyse the possibility of using esterification for the separation of lactic acid from acetic acid. The standard distillation approach does not allow for a high degree of separation, but a distillation step is possible for esters of both acids. As a result, high-purity ethyl lactate is obtained and, by introducing a hydrolysis step, pure lactic acid. The issue was analysed using Chemcad software with the UNIFAC thermodynamic model.