@article{TixGotthardtBodeetal.2024, author = {Tix, Julian and Gotthardt, Leon and Bode, Joshua and Karabacak, Burak and Nordmann, Janne and Hengsbach, Jan-Niklas and Ulber, Roland and Tippk{\"o}tter, Nils}, title = {Enhancement of succinic acid production by Actinobacillus succinogenes in an electro-bioreactor}, series = {Fermentation}, volume = {10}, journal = {Fermentation}, number = {10}, publisher = {MDPI}, address = {Basel}, issn = {2311-5637}, doi = {10.3390/fermentation10100504}, year = {2024}, abstract = {This work examines the electrochemically enhanced production of succinic acid using the bacterium Actinobacillus succinogenes. The principal objective is to enhance the metabolic potential of glucose and CO2 utilization via the C4 pathway in order to synthesize succinic acid. We report on the development of an electro-bioreactor system to increase succinic acid production in a power-2-X approach. The use of activated carbon fibers as electrode surfaces and contact areas allows A. succinogenes to self-initiate biofilm formation. The integration of an electrical potential into the system shifts the redox balance from NAD+ to NADH, increasing the efficiency of metabolic processes. Mediators such as neutral red facilitate electron transfer within the system and optimize the redox reactions that are crucial for increased succinic acid production. Furthermore, the role of carbon nanotubes (CNTs) in electron transfer was investigated. The electro-bioreactor system developed here was operated in batch mode for 48 h and showed improvements in succinic acid yield and concentration. In particular, a run with 100 µM neutral red and a voltage of -600 mV achieved a yield of 0.7 gsuccinate·gglucose-1. In the absence of neutral red, a higher yield of 0.72 gsuccinate·gglucose-1 was achieved, which represents an increase of 14\% compared to the control. When a potential of -600 mV was used in conjunction with 500 µg∙L-1 CNTs, a 21\% increase in succinate concentration was observed after 48 h. An increase of 33\% was achieved in the same batch by increasing the stirring speed. These results underscore the potential of the electro-bioreactor system to markedly enhance succinic acid production.}, language = {en} } @article{ChwallekNawrathKrastinaetal.2024, author = {Chwallek, Constanze and Nawrath, Lara and Krastina, Anzelika and Bruksle, Ieva}, title = {Supportive research on sustainable entrepreneurship and business practices}, series = {SECA Sustainable Entrepreneurship for Climate Action}, journal = {SECA Sustainable Entrepreneurship for Climate Action}, number = {3}, publisher = {Lapland University of Applied Sciences Ltd}, address = {Rovaniemi}, isbn = {978-952-316-514-4 (pdf)}, issn = {2954-1654 (on-line publication)}, pages = {67 Seiten}, year = {2024}, language = {en} } @article{ValeroFelderKrameretal.2024, author = {Valero, Daniel and Felder, Stefan and Kramer, Matthias and Wang, Hang and Carrillo, Jos{\´e} M. and Pfister, Michael and Bung, Daniel Bernhard}, title = {Air-water flows}, series = {Journal of Hydraulic Research}, volume = {62}, journal = {Journal of Hydraulic Research}, number = {4}, publisher = {Taylor \& Francis}, issn = {0022-1686 (Print)}, doi = {10.1080/00221686.2024.2379482}, pages = {319 -- 339}, year = {2024}, abstract = {High Froude-number open-channel flows can entrain significant volumes of air, a phenomenon that occurs continuously in spillways, in free-falling jets and in hydraulic jumps, or as localized events, notably at the toe of hydraulic jumps or in plunging jets. Within these flows, turbulence generates millions of bubbles and droplets as well as highly distorted wavy air-water interfaces. This phenomenon is crucial from a design perspective, as it influences the behaviour of high-velocity flows, potentially impairing the safety of dam operations. This review examines recent scientific and engineering progress, highlighting foundational studies and emerging developments. Notable advances have been achieved in the past decades through improved sampling of flows and the development of physics-based models. Current challenges are also identified for instrumentation, numerical modelling and (up)scaling that hinder the formulation of fundamental theories, which are instrumental for improving predictive models, able to offer robust support for the design of large hydraulic structures at prototype scale.}, language = {en} }