Real‐time dissolved carbon dioxide monitoring II: Surface aeration intensification for efficient CO₂ removal in shake flasks and mini‐bioreactors leads to superior growth and recombinant protein yields

Abstract

Mass transfer is known to play a critical role in bioprocess performance and henceforth monitoring dissolved O2 (DO) and dissolved CO2 (dCO2) is of paramount importance. At bioreactor level these parameters can be monitored online and can be controlled by sparging air/oxygen or stirrer speed. However, traditional small‐scale systems such as shake flasks lack real time monitoring and also employ only surface aeration with additional diffusion limitations imposed by the culture plug. Here we present implementation of intensifying surface aeration by sparging air in the headspace of the reaction vessel and real‐time monitoring of DO and dCO2 in the bioprocesses to evaluate the impact of intensified surface aeration. We observed that sparging air in the headspace allowed us to keep dCO2 at low level, which significantly improved not only biomass growth but also protein yield. We expect that implementing such controlled smart shake flasks can minimize the process development gap which currently exists in shake flask level and bioreactor level results.

What do masks mask? A study on transdermal CO2 monitoring

“…Our earlier approach is readily amenable to a wearable format (Fig. S9) by modifying a CO 2 sensor previously designed for bioprocess monitoring [ 38 , 39 ].…”

Effect of Air Sparging on Ethanol Production from Xylose and Glucose in Continuous Chemostat Fermentation Process Utilizing High Cell Density of <i>Candida intermedia</i> 4-6-4T2

“…The accumulated CO2 in the headspace of stirred tank reactors can affect the microbial physiology and may form a blanket ("blanket theory") without proper ventilation 13) . Thus, aeration through the air vents is likely to be insufficient, and air sparging is required for fermentation using high density of yeasts in stirred tank reactors 13),14) .…”

“…This phenomenon indicates that the equilibrium reaction tends to progress in accordance with the following formula: H2CO3 HCO3 -H CO2 H2O. Fermentation using high density of yeasts can be performed successfully without air sparging in an Erlenmeyer flask with a sponge plug, because sponge plugs are superior to dCO2 removal 12), 13) . In contrast, stirred tank reactors remove product gases from air vents, but the bottom area is small with greater depth.…”

An integrated microfluidic chip for alginate microsphere generation and 3D cell culture

“…[6][7][8] We consider that it is an important method to monitor and study pathogens in a controllable environment. 5,[9][10][11][12] To date, the conventional methods such as shake asks, 13,14 Petri dishes, 15 bioreactors 13 and multiwell plates 16 are still applied to culture and investigate pathogens. However, the operating procedures of conventional methods are complicated and time-consuming and can only provide limited control on pathogen culture.…”