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Electrochemical membrane-assisted pH-swing extraction and back-extraction of lactic acid
(Elsevier, 2022) Gausmann, Marcel; Bertram, Franziska; Schuur, Boelo; Jupke, Andreas; Gössi, Angelo; Riedl, Wolfgang
Reactive extraction of carboxylic acids such as lactic acid with tertiary amines is a state-of-the-art process but suffers strongly from reduced extraction efficiency in buffered environments like fermentation broths. In order to increase the efficiency of in-situ product removal, we here propose the combination of a membrane-assisted reactive extraction with an electrochemical pH shift. Prior to extraction in the membrane module, the fermentation broth containing the lactic acid at neutral pH is treated by anodic electrolysis to reduce the pH and thereby improve the extraction yield. Additionally, the cathodic reaction is used to increase the pH of the aqueous stream used for back-extraction of the loaded organic phase. Model solutions were used to develop a mathematical model, capable of calculating the required membrane area for in-situ extractions, considering the effect of the aqueous pH on the extraction performance. Additionally, using electrochemical pH shift, we were able to concentrate lactic acid from 1 wt% in the dilute broth to 7 wt% in the back extract.
01A - Beitrag in wissenschaftlicher Zeitschrift
Evaluation of dioxin induced transcriptomic responses in a 3D human liver microtissue model
(Elsevier, 2022) Tian, Mingming; Gou, Xiao; Zhang, Xiaowei; Messner, Catherine; Suter-Dick, Laura; Yan, Lu
Three-dimensional human liver microtissue model provides a promising method for predicting the human hepatotoxicity of environmental chemicals. However, the dynamics of transcriptional responses of 3D human liver microtissue model to dioxins exposure remain unclear. Herein, time-series transcriptomic analysis was used to characterize modulation of gene expression over 14 days in 3D human liver microtissues exposed to 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD, 31 nM, 10 ng/ml). Changes in gene expression and modulation of biological pathways were evaluated at several time points. The results showed that microtissues stably expressed genes related to toxicological pathways (e.g. highly of genes involved in external stimuli and maintenance of cell homeostasis pathways) during the 14-day culture period. Furthermore, a weekly phenomenon pattern was observed for the number of the differentially expressed genes in microtissues exposed to TCDD at each time point. TCDD led to an induction of genes involved in cell cycle regulation at day three. Metabolic pathways were the main significantly induced pathways during the subsequent days, with the immune/inflammatory response enriched on the fifth day, and the cellular response to DNA damage was identified at the end of the exposure. Finally, relevant transcription patterns identified in microtissues were compared with published data on rodent and human cell-line studies to elucidate potential species-specific responses to TCDD over time. Cell development and cytochrome P450 pathway were mainly affected after a 3-day exposure, with the DNA damage response identified at the end of exposure in the human microtissue system but not in mouse/rat primary hepatocytes models. Overall, the 3D human liver microtissue model is a valuable tool to predict the toxic effects of environmental chemicals with a relatively long exposure.
01A - Beitrag in wissenschaftlicher Zeitschrift
How to Foster ‘New Approach Methodology’ Toxicologists
(SAGE, 18.02.2022) Doktorova, Tatyana Y.; Azzi, Pamela; Hofer, Joelle; Werner, Sophie; Singh, Pranika; Hardy, Barry; Chesne, Christophe; Messner, Catherine; Gaiser, Carine; Suter-Dick, Laura
The need to reduce, refine and replace animal experimentation has led to a boom in the establishment of new approach methodologies (NAMs). This promising trend brings the hope that the replacement of animals by using NAMs will become increasingly accepted by regulators, included in legislation, and consequently more-often implemented by industry. The majority of NAMs, however, are still not very well understood, either due to the complexity of the applied approach or the data analysis workflow. A potential solution to this problem is the provision of better educational resources to scientists new to the area — showcasing the added value of NAMs and outlining various ways of overcoming issues associated with knowledge gaps. In this paper, the educational exchange between four institutions — namely, two universities and two SMEs — via a series of video training sessions, is described. The goal of this exchange was to showcase an exemplary event to help introduce scientists to non-animal approaches, and to actively support the development of resources enabling the use of alternatives to laboratory animals.
01A - Beitrag in wissenschaftlicher Zeitschrift

Institut für Chemie und Bioanalytik

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