Speaker
Description
The wide variety of microbial processes provides a flexible biotechnological platform for polymer production. In this study, Azotobacter vinelandii is used to produce the polysaccharide alginate. Alginate is used in the food industry and has many medical applications. It consists of two linearly linked co-polymers: α-L-guluronic acid and (1-4)-β-D-mannuronic acid. The properties of alginate depend on the amount and composition of these sugar acids. Currently, alginate is produced from seaweeds (40.000 t/year). However, the composition of alginate can hardly be controlled during the growth of the seaweeds in the marine environment (Hay et al., 2013). More control options for tailor-made polymer production are arising from the use of microorganisms such as A. vinelandii in a bioreactor setup. Furthermore, bioreactors that enable biofilm formation can potentially enhance the growth and production efficiency because of the high surface-to-volume ratio. Biofilms are structured communities of microorganisms embedded in a self-produced, extracellular polymeric matrix consisting of extracellular polysaccharides (EPS) protecting the cells from environmental influences (Kapellos et al., 2015). A. vinelandii is able to grow as a biofilm while producing alginate as EPS component. Productivity can be improved by using porous support structures with large internal surface area. However, experimental investigation is challenging for such structures, wherefore in-silico methods are often proposed. An in-house mathematical model for the prediction of biomass growth in porous structures was recently developed (Aamer et al., 2026). Currently, no experimental data on the biofilm growth of A. vinelandii in porous structures are available that would allow the application of the computational model to the investigation of A. vinelandii.
For this purpose, we develop experiments with microfluidic devices, that enable the visualization of A. vinelandii growth in single pores and provide information about growth kinetics. These experiments aim to quantify the time-dependent biofilm growth and alginate production obtained under given nutrient and oxygen concentrations in the feed. The small dimensions of microfluidic devices require appropriate measurement methods. One option is the optical visualization of biofilm formation and growth. The gathered data can be used to parametrize the model kinetics. In this study, we will present our initial experimental results using microscopy techniques and the microfluidic device to observe biofilm growth in single pore structures. These will lead to a solid understanding of A. vinelandii biofilm formation which can be used for the development of a biofilm reactor with a competitive alginate yield.
Acknowledgment:
The authors gratefully acknowledge the funding by the European Regional Development Fund (ERDF) within the programme Research and Innovation - Grant Number ZS/2023/12/182075.
| References | Iain D. Hay, Zahid Ur Rehman, M. Fata Moradali, Yajie Wang, and Bernd H. A. Rehm. Microbial alginate production, modification and its applications. Microbial Biotechnology, 6(6):637–650, 2013. DOI: 10.1111/1751-7915.12076; George E. Kapellos, Terpsichori S. Alexiou, and Stavros Pavlou. Chapter 8 - fluid-biofilm interactions in porous media. In Sid M. Becker and Andrey V. Kuznetsov, editors, Heat Transfer and Fluid Flow in Biological Processes, pages 207–238. Academic Press, Boston, 2015. ISBN 978-0-12-408077-5. DOI: 10.1016/B978-0-12-408077-5.00008-0; Aamer, E., Faber, F., Bhaskaran, S. et al. Pore Network Model for Study of Biofilm Growth Limitations in Porous Substrata. Transp Porous Med 153, 12 (2026). DOI: 10.1007/s11242-025-02261-6 |
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| Country | Germany |
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