Microscale Atmospheric Pressure Plasma Jet as a Source for Plasma‐Driven Biocatalysis

Abstract

The use of a microscale atmospheric pressure plasma jet (μAPPJ) was investigated for its potential to supply hydrogen peroxide in biocatalysis. Compared to a previously employed dielectric barrier discharge (DBD), the μAPPJ offered significantly higher H2O2 production rates and better handling of larger reaction volumes. The performance of the μAPPJ was evaluated with recombinant unspecific peroxygenase from Agrocybe aegerita (rAaeUPO). Using plasma‐treated buffer, no side reactions with other plasma‐generated species were detected. For long‐term treatment, rAaeUPO was immobilized, transferred to a rotating bed reactor, and reactions performed using the μAPPJ. The enzyme had a turnover of 36,415 mol mol−1 and retained almost full activity even after prolonged plasma treatment. Overall, the μAPPJ presents a promising plasma source for plasma‐driven biocatalysis.

Plasma‐driven biocatalysis: In situ hydrogen peroxide production with an atmospheric pressure plasma jet increases the performance of OleTJE when compared to adding the same molar amount of hydrogen peroxide in bolus

“…Finding an effective way to immobilize OleT JE , as has been done previously with enzymes treated with plasma, would be a logical next step. [24,26,49] According to these findings, being able to treat OleT JE with longer, continuous plasma treatment over shorter, consecutive plasma treatments will be important for maintaining optimal concentrations of H 2 O 2 and decreasing the percentage of products that are fatty alcohols instead of the desired terminal alkenes. However, OleT JE and the OleT JE -SOR fusions lose activity after 2 min of plasma treatment.…”

“…Atmospheric pressure plasmas have been explored for biocatalysis with the enzymes horseradish peroxidase (HRP) and the modified fungal peroxygenase from Agrocybe aegerita (rAaeUPO) in experiments performed by Yayci et al [24][25][26] One of the first methods used was a dielectric barrier discharge (DBD) plasma to generate H 2 O 2 , the reaction mediator for HRP, as a proof of concept. However, HRP lost activity after about 5 min of treatment, which was found to be likely due to heme degradation.…”

“…[26] In addition, this method was only able to treat very small volumes of solution at a time (µl), and the solution was exposed to DBD-generated UV photons that can be damaging to enzymes. [26][27][28] To address these DBD limitations, further experiments were conducted by Yayci et al [24] with a microscale atmospheric pressure plasma jet (µ-APPJ), which was used in conjunction with a rotating bed reactor. This was found to be very efficient for rAaeUPO catalysis.…”

“…The highest turnover achieved was 36 415, though this could have been higher if the reactor was allowed to continue operation until rAaeUPO completely lost activity. [24] In this study, a similar type of µ-APPJ, the Cooperation in Science and Technology (COST) Reference Microplasma Jet (COST-Jet) [29] was used for the generation of H 2 O 2 as the reaction mediator for the cytochrome P450 fatty acid peroxygenase, OleT JE . As with the previous plasma-driven biocatalysis experiment, we generate the reaction mediator in situ to avoid unnecessary dilution and try to increase the TONs by protecting OleT JE from an excess of H 2 O 2 .…”

Using auxiliary electrochemical working electrodes as probe during contact glow discharge electrolysis: A proof of concept study

“…Gas-phase plasma can be used in a similar way to modify the plasma electrode or the properties of a substrate placed close to the plasma source. Related to catalytic applications, the gas-phase plasma can also be used, e.g., to change the mechanism of a catalytic reaction on the target (gas-phase plasma catalysis) [21][22][23] or to tailor the structural properties of the target, for example, to form catalyst materials with distinct (electro)catalytic properties. [24][25][26][27] In contrast, much less is known about the effect of in-liquid plasma on target materials.…”