TY  - JOUR
A1  - Tix, Julian
A1  - Gotthardt, Leon
A1  - Bode, Joshua
A1  - Karabacak, Burak
A1  - Nordmann, Janne
A1  - Hengsbach, Jan-Niklas
A1  - Ulber, Roland
A1  - Tippkötter, Nils
T1  - Enhancement of succinic acid production by Actinobacillus succinogenes in an electro-bioreactor
JF  - Fermentation
N2  - 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.
KW  - A. succinogenes
KW  - power-to-X
KW  - electrofermentation
KW  - electro-bioreactor
KW  - succinate
Y1  - 2024
U6  - https://doi.org/10.3390/fermentation10100504
SN  - 2311-5637
N1  - Corresponding author: Nils Tippkötter
N1  - This article belongs to the Special Issue "Advance in Microbial Electrochemical Technologies"
VL  - 10
IS  - 10
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Chwallek, Constanze
A1  - Nawrath, Lara
A1  - Krastina, Anzelika
A1  - Bruksle, Ieva
T1  - Supportive research on sustainable entrepreneurship and business practices
JF  - SECA Sustainable Entrepreneurship for Climate Action
Y1  - 2024
SN  - 978-952-316-514-4 (pdf)
SN  - 2954-1654 (on-line publication)
IS  - 3
PB  - Lapland University of Applied Sciences Ltd
CY  - Rovaniemi
ER  - 
TY  - JOUR
A1  - Valero, Daniel
A1  - Felder, Stefan
A1  - Kramer, Matthias
A1  - Wang, Hang
A1  - Carrillo, José M.
A1  - Pfister, Michael
A1  - Bung, Daniel Bernhard
T1  - Air–water flows
JF  - Journal of Hydraulic Research
N2  - 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.
Y1  - 2024
U6  - https://doi.org/10.1080/00221686.2024.2379482
SN  - 0022-1686 (Print)
SN  - 1814-2079 (Online)
VL  - 62
IS  - 4
SP  - 319
EP  - 339
PB  - Taylor & Francis
ER  -