Evaluation of lactic acid purification from fermentation broth by hybrid short path evaporation using factorial experimental design

• Lactic acid purification using hybrid short path evaporation was studied.
• Feed flow rate, agitation, condenser and evaporator temperature was varied.
• The process is technically feasible and advantageous.
• Lactic acid purity around 89.7% was obtained.

This work describes the evaluation of lactic acid purification from fermentation broth by hybrid short path evaporation. The proposed hybrid purification process consists of an evaporation system composed by a cylindrical wiped film evaporator with two condensers, one located internally and other externally to the evaporator. Through factorial experimental design, the influence of operation conditions as feed flow rate, agitation, condenser and evaporator temperature on residue and distilled percentages, lactic acid purity and recovery were studied. Models were developed in order to describe the response of interest as function of operating conditions. The results showed that with a high operating pressure (in terms of short path evaporation), with a pressure of 1000 Pa, and one step of separation, lactic acid purity around 89.7% was obtained which was about 18 times lactic acid concentration higher than the initial content in raw material.