Oscillating flow bioreactors: An enabling technology for sustainable biorefining operations?

Abstract

In this work a novel reactor is evaluated on its potential to intensify biobased processing via a novel potentially continuous enzymatic hydrolysis process. An oscillatory flow bioreactor is applied in batch and recirculating mode, the latter mimicking the flow pattern of a continuous process. The recirculating mode operation can intensify cellulose conversion to hydrolyzed sugar liquid significantly, namely with enabling high solid processing and reaching >10% higher cellulose conversion than the respective operation in batch mode. Resulting sugar concentrations reach >90 mg/mL with the potential to enable the elimination of further concentration steps in down-stream processing, having a positive impact on the overall efficiency and sustainability of further processing steps to biofuels or biochemicals. K E Y W O R D S enzymatic hydrolysis, continuous processing, oscillatory flow

Revisiting the Effect of U-Bends, Flow Parameters, and Feasibility for Scale-Up on Residence Time Distribution Curves for a Continuous Bioprocessing Oscillatory Baffled Flow Reactor

“…It is noted that although maximizing plug flow conditions may appear optimal, they may not be suitable for all reactor applications, in this case, bioprocesses. For example, on the one hand, in a study where enzymatic hydrolysis is conducted, high velocity ratios compared to this study were used to ensure adequate mixing and full suspension of solids occurred . On the other hand, high velocity ratios imply higher shear stress rates on cellular cultures, which could be detrimental during cultivation …”

“…As discussed, a lower f (<0.5 Hz) implies a higher TiS (>8), as shown in Figure b, as indicated by the bright red region in the bottom left figure. The issue with running low f within OBR systems concerns the possibility of fouling or dead spots occurring due to the lack of energy to fully suspend particles, for example, in crystallization reactions . In theory, provided ψ remains around the value of 2, a higher f can be used to maximize the TiS value.…”

“…For example, on the one hand, in a study where enzymatic hydrolysis is conducted, high velocity ratios compared to this study were used to ensure adequate mixing and full suspension of solids occurred. 45 On the other hand, high velocity ratios imply higher shear stress rates on cellular cultures, which could be detrimental during cultivation. 16 As discussed, a lower f (<0.5 Hz) implies a higher TiS (>8), as shown in Figure 6b, as indicated by the bright red region in the bottom left figure.…”

“…The issue with running low f within OBR systems concerns the possibility of fouling or dead spots occurring due to the lack of energy to fully suspend particles, for example, in crystallization reactions. 45 In theory, provided ψ remains around the value of 2, a higher f can be used to maximize the TiS value. A similar observation can be made for x O .…”

Special issue covering the Second International Process Intensification Conference (IPIC2)

“…In the selected papers for this special issue, Boffito et al 1 discuss distributed production as a scale‐up approach using the case study of a microrefinery gas‐to‐liquid unit to convert natural gas into Fischer‐Tropsch fuels. Muster‐Slawitsch et al 2 analyze oscillating flow bioreactors for sustainable biorefining operations. Operating the oscillatory flow reactor in recirculation mode enables high solid processing and thus an avenue to further increase the efficiency of the process.…”