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Research
Small spheres save enzymes for biocatalysis
Plasmas can supply the co-substrate for the biocatalysis of valuable substances, but pity the enzymes. If the latter are attached to small spheres, they work protected and up to 44 times longer.
Some enzymes, such as the one from fungi studied here, are able to produce valuable substances such as the fragrance (R)-1-phenylethanol. To do this, they convert a less expensive substrate using a cosubstrate. A research team from the Department of Biology at Ruhr-Universität Bochum came up with the idea of supplying them with this cosubstrate via a plasma - a crazy idea, as plasmas generally have a destructive effect on biomolecules. However, using several tricks, the researchers led by Prof. Dr. Julia Bandow and Dr. Tim Dirks succeeded. They have now refined one of these tricks and thus improved the process: they attach the enzymes to small balls to hold them to the bottom of the reactor and like this protect them from the harmful influence of the plasma. By choosing the most suitable type of ball, they were able to increase the stability of the enzyme 44-fold. They report in the Journal of the Royal Society Interface from October 25, 2023.
Model enzyme from an edible mushroom
"In plasma-driven biocatalysis, we want to operate enzymes that use hydrogen peroxide to convert a substrate into a more valuable product using technical plasmas," explains Julia Bandow, Head of the Chair of Applied Microbiology. The plasmas - energetically charged gases - produce hydrogen peroxide as well as a variety of reactive species.
The researchers use the non-specific peroxigenase (AaeUPO) from the edible fungus Agrocybe aegerita as a model enzyme. In initial studies, they were able to show that although plasma-driven biocatalysis works with it, there are also key limitations. "The decisive factor was that the enzymes react sensitively to the plasma treatment and are therefore inactivated within a short period of time," explains Tim Dirks, first author of the current study. "To prevent this, we use the method of enzyme immobilization, i.e. attaching the enzymes to so-called beads: small spheres with a porous surface."
Spheres keep the enzymes at the bottom
Due to gravity, these spheres lie on the bottom of the sample and provide a protective zone between the plasma phase at the top and the enzymes. The research team observed early on that the choice of different immobilization methods also led to different survival rates of enzymes. The aim of the current study was therefore to investigate the effect of different immobilization methods on the plasma stability of enzymes using a larger selection of enzymes.
Five different enzymes were selected, two of which also convert hydrogen peroxide and three of which do not require hydrogen peroxide for their activity. The researchers tested nine different types of beads, some of which had a resin surface and others a silica surface with or without a polymer coating. After immobilization, the enzymes were treated with plasma for up to five minutes. The researchers then compared their residual activity with untreated controls.
The path to new applications
The beads with resin surfaces showed the best results for all five enzymes. "The amino and epoxy-butyl beads performed best," like these," says Tim Dirks. In both cases, the enzymes form a strong, covalent bond with the carrier material, which cannot be dissolved. "This type of immobilization appears to limit the mobility of the enzymes, which makes them less susceptible to plasma-induced inactivation," concludes Tim Dirks. The team extended the plasma treatment times for the most promising candidates to up to one hour and, like this, was able to increase the stability of the enzymes under plasma treatment by up to a factor of 44 through immobilization. "The findings of this study thus pave the way for new applications that aim to combine enzymes with technical plasmas in the future," the researchers like this.
adapted from Maike Drießen, RUB
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Awards
Prof. Dr. Beatriz Roldán Cuenya honored with Manchot Research Professorship
Prof. Beatriz Roldán Cuenya was awarded the Manchot Research Professorship, becoming the first woman to receive this prestigious honor. The award is presented annually by the Jürgen Manchot Foundation to outstanding scientists. In addition to recognizing her exceptional scientific contributions, the foundation provides the opportunity for the award winner to teach at the Chemistry Faculty of the Technical University of Munich.
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Internationalization
Judith Golda Shines at AVS 69th International Symposium
Judith Golda, representing CRC 1316, captivated audiences at the AVS 69th International Symposium in Portland, Oregon, from November 5-10, 2023. Her invited talk, "Fundamentals of atmospheric pressure discharges for plasma catalytic applications," highlighted the critical role of atmospheric pressure discharges in plasma catalysis. Her presentation presented theory and application, emphasizing the transformative potential of understanding these discharges for catalytic processes in industries, environmental remediation, and energy production.
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Project Area Meetings
CRC 1316 Project Area A (November 9) and Project Area B (November 10)
The CRC 1316 (Collaborative Research Center) brought together members from Project Area A on November 9 and Project Area B on November 10 for two consecutive days of intensive discussions, presentations, and collaborations. The primary objective of the meeting was to review recent project developments, share results, and facilitate further cooperation among team members.
The meeting commenced with a welcome address, setting the stage for a day of fruitful discussions. Each sub-project presented its recent findings, outlining progress, challenges faced, and proposed strategies for overcoming obstacles. The presentations sparked engaging discussions, providing valuable insights and suggestions from fellow researchers.
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Crash Course
Heterogeneous Catalysis and Plasma Catalysis
On 8.11.2023, Leon Leffers (Univ. Twente) provided a crash course on heterogeneous catalysis and the prospect and principles of plasma catalysis. ECRs and PIs from the various disciplines of the CRC attended this crash course and discussed the details of connecting plasma phenomena to catalytic surface processes.
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News
Catalysis at surfaces
In the new textbook "Catalysis at Surfaces", CRC 1316 project leader and vice-spokesperson Martin Muhler, together with colleagues W.Grünert and W.Kleist, have contributed to view surface catalysis as a truly interdisciplinary field that includes chemistry, physics, and engineering. The synthesis, the modification of porous solids as well as the bulk- and surface-sensitive characterization techniques are shown. Insight is provided into the most important aspects of surface catalysis, thermal catalysis, and photo- and electrocatalysis as future fields of the energy transition.
This textbook is recommended for Master's and Ph.D. students to get deeper into all relevant aspects of catalyst synthesis, characterization, and application in suitable reactors.
The pdf version is free of charge for all RUB members.
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Public Relations
Plasma physics events for high school students
The project week for high school students at Ruhr University Bochum is an educational program of the CRC 1316, the Faculty of Physics and Astronomy at the RUB, and of di. The student project week takes place twice a year during the Easter vacations and during the autumn vacations.
From April 3rd to 6th, the project week was hosted for over 60 female students in grades 8 to 10. The girls chose between four workshops: plasma physics, astronomy, physics in medicine, and House of the Future. The project "From Plasma to Gold Layers" allows the students to gain an insight into the generation and applications of plasmas. Using the sputter coater and professional laboratory equipment, the students could deposit and examine gold layers themselves. During the project week, the students attended a lecture by Prof. Dr. Judith Golda on "hands-on plasmas – between material science and medicine "and visited laboratories and the Planetarium Bochum. On the closing day, the results of the students' research were presented in a poster session, followed by a quiz and lunch. The next project week Autumn for female and male students in grades 8 and 9 will occur from the 9th to the 13th of October.
The Faculty of Physics enables students to complete a school internship in Physics.
From March 27th to 31st, we welcomed two interns from grade 9. After a short introduction to plasma physics, the students worked on the sputter coater. They examined the coated samples. For this purpose, they determined the transmission with a spectrometer, the layer thickness with the profilometer, and the conductivity. The interns also gained experience in handling data and in data evaluation. The goal of the internship is also to give an impression of laboratory work and current research. Therefore, doctoral students, bachelor's, and master's students guided the interns through the labs and presented their experiments. The interns also visited the NRW state competition "Jugend forscht," which took place at the Ruhr University Bochum from 27th to 29th March.
The "mobile plasma workshop" took place for the first time on June 5th. Our plasma truck visited an 11th-grade physics class at school. In the beginning, the students watched a short movie and received basic knowledge about plasmas and their applications. After a quick quiz, they worked on the experiments in smaller groups. The students examined the light emitted by plasmas with an optical spectrometer and observed how electric and magnetic fields can influence plasmas. Information on the experiments on the students' iPads guided the workshop. The workshop was a success, and the students showed great interest. As an advanced course in physics, they already had a good understanding of electric and magnetic fields. However, plasma physics is not part of the school curriculum. Through the students' feedback, we have gained insights on how to improve our workshop going forward.
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Rolduc
Summer Meeting CRC 1316
From June 19 to 21, 2023, the CRC 1316 Summer Meeting has been held at Rolduc Abbey. The meeting was a great success and was accompanied by a lively participation of all stakeholders.
The event provided an excellent opportunity for scientists to present and discuss their research results.
In addition to the lectures, there were also many opportunities for informal talks and discussions. These discussions led to an intensification of collaboration and offered participants the opportunity to establish new contacts and deepen existing relationships.
Rolduc Abbey provided an excellent backdrop for the meeting. The historic buildings and idyllic surroundings contributed to a relaxed and productive atmosphere.
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Conference
Heraeus Seminar "Non thermal plasmas for sustainable chemistry"
The SFB 1316 was involved in the organization of the 785 WE Heraeus Seminar "Non thermal plasmas for sustainable chemistry" that was held in Bad Honnef 22.4.-27.4.2023. The meeting was organized by Yiguang Yu (Princeton), Tomo Nozaki (Tokyo Tech), Annemie Bogaerts (U Antwerp), and A. von Keudell (RUB, SFB 1316). The SFB 1316 contributed with two invited presentations and 6 posters. The seminar with 80 attendees provided a broad overview on the field and critical discusssions about the challenges and potential of plasma methods for sustainable chemistry.