Kinetic studies of bifurcating flavoproteins.

Since their original proposal in 2008, a number of broadly distributed flavoprotein systems catalyzing electron bifurcation have been identified that play key roles in the bioenergetics of anaerobic bacteria and archaea. While the overall thermodynamics of flavin-based electron bifurcation are now quite well-understood, the same cannot be said of their kinetic behavior. The present account represents a summary of results obtained with several electron-electron bifurcating systems, shamelessly focusing on work done in the authors' laboratory.

Molybdenum-containing CO dehydrogenase and formate dehydrogenases.

The molybdenum-containing CO dehydrogenase and the formate dehydrogenases catalyze important interconversions of one-carbon compounds, the former oxidizing CO to CO, and the latter the reversible interconversion of CO and formate. Methodologies to study these two enzymes are discussed.

Mechanism of Action of Formate Dehydrogenases.

The molybdenum- and tungsten-containing formate dehydrogenases from a variety of microorganisms catalyze the reversible interconversion of formate and CO; several, in fact, function as CO reductases in the reverse direction under physiological conditions. CO reduction catalyzed by these enzymes occurs under mild temperature and pressure rather than the elevated conditions required for current industrial processes. Given the contemporary importance of remediation of atmospheric CO to address global warming, there has been considerable interest in the application of these enzymes in bioreactors.

The rapid-reaction kinetics of an electron-bifurcating flavoprotein, the crotonyl-CoA-dependent NADH:ferredoxin oxidoreductase EtfAB:bcd.

We have investigated the kinetic behavior of the electron-bifurcating crotonyl-CoA-dependent NADH: ferredoxin oxidoreductase EtfAB:bcd from Megasphaera elsdenii. The overall behavior of the complex in both the reductive and the oxidative half-reactions is consistent with that previously determined for the individual EtfAB and bcd components. This includes an uncrossing of the half-potentials of the bifurcating flavin of the EtfAB component in the course of ferredoxin-reducing catalysis, ionization of the bcd flavin semiquinone and the appearance of a charge transfer complex upon binding of the high potential acceptor crotonyl-CoA.

Predictive modeling for cell culture in commercial manufacturing of biotherapeutics.

The biopharmaceutical industry continually seeks advancements in the commercial manufacturing of therapeutic proteins, where mammalian cell culture plays a pivotal role. The current work presents a novel data-driven predictive modeling application designed to enhance the efficiency and predictability of cell culture processes in biotherapeutic production. The capability of the cloud-based digital data science application, developed using open-source tools, is demonstrated with respect to predicting bioreactor potency from at-line process parameters over a 5-day horizon.