Determination of kinetic parameters of fermentation processes by a continuous unsteady‐state method: Application to the alcoholic fermentation of D‐xylose by Pichia stipitis

A quick technique for determination of kinetic parameters of fermentation processes is proposed and applied to the transformation of D‐xylose into ethanol by Pichia stipitis. The commonly used method to evaluate these parameters is based on achieving several steady states. In the proposed procedure, μ_m and K_s can be determined from only one steady state, by provoking a disturbance over it, after allowing the system to return to the original conditions. The main difference between the steady and unsteady state methods is the required fermentation time; while the former method lasted 350 h, the latter required a period 25 times lower. Kinetic and stoichiometric parameters were determined with both methods under anoxic and limited oxygen concentration conditions. Results from the two methods were compared, giving only 2% and 4.5% differences in the values of K_s and μ_m and a little over 4% for μ_m were the deviations under the latter ones. © 1993 Wiley & Sons, Inc.