Fouling Mechanisms in the Clarification of 1,3-Propanediol Fermentation Broths by Membrane Processes

Membrane separation is an effective means of separating 1,3-propanediol (1,3-PD) from fermentation broth. However, systematic studies on membrane fouling behavior during this process are still limited. Therefore, this study systematically analyzed the membrane fouling behavior during the clarification of 1,3-PD fermentation broth using ultrafiltration/microfiltration and explored the effects of different membrane materials, pore sizes, and shear rates on permeation efficiency, target product recovery rate, and impurity removal rate. The results showed that the filtration of 1,3-PD fermentation broth was mainly dominated by cake formation, and the main foulant was identified as proteinaceous substances. Otherwise, increasing the shear rate adjacent to the membrane did not alter the membrane pore fouling mechanism, but it can disrupt the reversible fouling layer and reduce the growth rate of the fouling layer. Meanwhile, the results also indicated that the PES 100 kDa membrane exhibited the best overall performance with high recovery rate of 1,3-PD and excellent removal effects on impurities, significantly reducing the subsequent purification burden. This study provides more theoretical basis and data support for the optimization of membrane separation processes in 1,3-PD fermentation broth clarification.