Multienzymatic cascade reactions have garnered the attention of many researchers as an approach for
converting CO2 into methanol. The cascade reaction used in
this study includes the following enzymes: a formate
dehydrogenase (ClFDH), a formaldehyde dehydrogenase
(BmFaldDH), and an alcohol dehydrogenase (YADH) from
Clostridium ljungdahlii, Burkholderia multivorans, and Saccharomyces cerevisiae, respectively. Because this cascade reaction
requires NADH as a cofactor, phosphite dehydrogenase
(PTDH) was employed to regenerate the cofactor. The
multienzymatic cascade reaction, along with PTDH, yielded
3.28 mM methanol. The key to the success of this cascade
reaction was a novel formaldehyde dehydrogenas... More
Multienzymatic cascade reactions have garnered the attention of many researchers as an approach for
converting CO2 into methanol. The cascade reaction used in
this study includes the following enzymes: a formate
dehydrogenase (ClFDH), a formaldehyde dehydrogenase
(BmFaldDH), and an alcohol dehydrogenase (YADH) from
Clostridium ljungdahlii, Burkholderia multivorans, and Saccharomyces cerevisiae, respectively. Because this cascade reaction
requires NADH as a cofactor, phosphite dehydrogenase
(PTDH) was employed to regenerate the cofactor. The
multienzymatic cascade reaction, along with PTDH, yielded
3.28 mM methanol. The key to the success of this cascade
reaction was a novel formaldehyde dehydrogenase,
BmFaldDH, the enzyme catalyzing the reduction of formate
to formaldehyde. The methanol yield was further improved by incorporation of 1-ethyl-3-methylimidazolium acetate (EMIMAc), resulting in 7.86 mM of methanol. A 500-fold increase in total turnover number was observed for the ClFDH-BmFaldDHYADH cascade system compared to the Candida boidinii FDH-Pseudomonas putida FaldDH-YADH system. We provided
detailed insights into the enzymatic reduction of CO2 by determining the thermodynamic parameters (Kd and ΔG) using
isothermal titration calorimetry. Furthermore, we demonstrated a novel time-dependent formaldehyde production from CO2.
Our results will aid in the understanding and development of a robust multienzyme catalyzed cascade reaction for the reduction
of CO2 to value-added chemicals.