Efficient Separation of a Novel Microbial Chassis, <i>Vibrio natriegens</i>, from High-Salt Culture Broth Using Ceramic Ultrafiltration Membranes

Abstract

Vibrio natriegens is widely used as a production host for biotechnological processes due to its superior maximum glucose consumption rate, high growth rate, and abundant ribosomes. Most bioprocesses also need a scalable biomass separation step. This can be achieved by cross-flow filtration with ceramic membranes, although the membrane pores are susceptible to fouling. However, the fouling characteristics of V. natriegens culture broth have not been investigated in detail. We therefore characterized membrane fouling during the separation of V. natriegens biomass from culture broth using a cross-flow filtration plant with ceramic membranes. The resistance in series model was used to quantify the fouling-induced resistance caused by the different components of the culture broth. The total fouling resistance was 4.1·109 ± 0.6·109 m−1 for the culture broth and 5.4·109 ± 0.7·109 m−1 for the summed broth components. Reversible resistance accounted for 86% and 81% of these totals, respectively. We then applied Hermia’s adapted filtration laws to determine the dominant fouling mechanism induced by the different broth components. In a further step, we established a setup to determine the compressibility index of the cells during cross-flow filtration, resulting in an estimated value of 0.55 ± 0.04. These results will facilitate the design of economic filtration plants and will help to establish V. natriegens as a production host for large-scale industrial processes.

Keywords

• fouling
• <i>Vibrio natriegens</i>
• compressibility index
• resistance in series model
• Hermia’s laws
• ceramic membranes