Development of a novel microplate for high‐throughput screening and optimization of DHA producing strains based on CFD technology

Abstract

Microtiter plates are suitable for screening and process development of most microorganisms. They are currently the container of choice for high‐throughput and small‐scale microbial culture, but require optimization for specific work. In this research, a novel type of microtiter plate was developed using computational fluid dynamics (CFD) technology. The new plate provided high oxygen supply and optimal mixing effects for the fermentation culture of docosahexaenoic acid (DHA) producing strains, surpassing the conventional method of strain screening with shake flasks, which was insufficient. The shape of the microtiter plate was modified, and baffles were introduced to improve mass transfer and oxygen supply effects in the vibrating bioreactor. CFD technology was used to model the new plate's characteristics, establishing the superiority of hexagonal microtiter plates with six baffles. Parameters in the incubation process, such as vibration frequency and liquid load, were optimized, and the final result achieved an oxygen transfer coefficient (KLa) of 0.61 s−1 and a volume power input of 2364 w m−3, which was four to five times better than the original 96‐well plate. The culture results optimized by the model were also verified. Therefore, this new microtiter plate provides a powerful tool for future high‐throughput screening of strains.

Validation of computational fluid dynamics of shake flask experiments at moderate viscosity by liquid distributions and volumetric power inputs

“…CFD is already routinely used for STRs with great success to calculate mixing times and inhomogeneities, the k L a, gas hold-up, volumetric power input and shear stress 3 – 13 . In contrast, CFD applications for small scale, shaken bioreactors, such as microtiter plates 14 – 18 and shake flasks 19 – 22 , are scarce in the scientific literature. Zhang et al used a CFD model for shake flasks to calculate the volumetric power input and k L a for a variety of shaking parameters 19 .…”

“…CFD models have also been already used for the development of novel shaken bioreactor designs 23 , 24 . For example, He et al used a CFD model, employing a RNG k-epsilon turbulence model, to design a novel well type for microtiter plates, computing the k L a at a variety of shaking conditions, including viscosities of up to 30 mPa∙s 18 .…”