Fine Bubble‐based CO₂ Capture Mediated by Triethanolamine Coupled to Whole Cell Biotransformation

Abstract

Carbon capture technology can be set up in combination with biocatalysis to utilize the bound CO2 as substrate in the Kolbe‐Schmitt like enzymatic reaction. The exemplary whole cell biotransformation of catechol to 2,3‐dihydroxybenzoic acid in a triethanolamine‐mediated multiphase system shows increased equilibrium conversion. Apart from the beneficial thermodynamics, the inherent fluid properties of triethanolamine is enabling easy application of CO2 fine bubbles as highly efficient gassing method to minimize the CO2 demand and CO2 emissions.

Microbubble enhanced mass transfer efficiency of CO2 capture utilizing aqueous triethanolamine for enzymatic resorcinol carboxylation

“…From previous studies, it is known that the 0.5 μm sparger produces slightly smaller bubbles with d 50 of 79 μm compared to 109 μm for the 2 μm sparger in 1 M TEA at 20 ml min −1 CO 2 in a bubble column setup. 11 The same effect is observed in the measurement with a flow rate of 100 ml min −1 . Contrary to that, the utilization of the 10 μm sparger results in a much lower k L a , which can be explained by formation of bigger bubbles due to lower pore size dependent capillary pressure that need to be overcome for bubble growth.…”

“…The separation was performed according to the previously reported protocol. 11 Typical retention times were 7.0 min for resorcinol and 8.3 min for 2,6-dihydroxybenzoic acid.…”

“…Previous studies showed that higher amine concentrations improved the achievable yield in the thermodynamic limited biotransformation as well as reduced the produced bubble sizes when using membrane spargers. 11 Even microbubble aeration, which is defined as aeration with bubbles smaller than 100 μm in diameter, 12 was achieved. Utilizing microbubbles provides a high volume specific surface area as well as shrinking behavior coupled with accelerated dissolution assisted by the Laplace pressure to enhance the mass transfer.…”

Synthetic Enzyme‐Catalyzed CO2 Fixation Reactions

“…achieved subtle improvements in conversion with the same enzyme system. They attributed this improvement (16.1 % to 25.7 %) to the higher concentration of amine mediator (1 M vs 3 M), which in turn allowed CO 2 to be supplied as ‘fine bubbles’ [98] …”

“…However, the efficiency of the system reported by Ohde et al. depends on the type and concentration of the amine mediator, the downstream derivation agent, and reaction conditions [98] …”