Coupling an Electroactive Pseudomonas putida KT2440 with Bioelectrochemical Rhamnolipid Production

Microorganisms, vol. 8, pp. 1959

Abstract

Sufficient supply of oxygen is a major bottleneck in industrial biotechnological synthesis. One example is the heterologous production of rhamnolipids using Pseudomonas putida KT2440. Typically, the synthesis is accompanied by strong foam formation in the reactor vessel hampering the process. It is caused by the extensive bubbling needed to sustain the high respirative oxygen demand in the presence of the produced surfactants. One way to reduce the oxygen requirement is to enable the cells to use the anode of a bioelectrochemical system (BES) as an alternative sink for their metabolically derived electrons. We here used a P. putida KT2440 strain that interacts with the anode using mediated extracellular electron transfer via intrinsically produced phenazines, to perform heterologous rhamnolipid production under oxygen limitation. The strain P. putida RL-PCA successfully produced 30.4 ± 4.7 mg/L mono-rhamnolipids together with 11.2 ± 0.8 mg/L of phenazine-1-carboxylic acid (PCA) in 500-mL benchtop BES reactors and 30.5 ± 0.5 mg/L rhamnolipids accompanied by 25.7 ± 8.0 mg/L PCA in electrode containing standard 1-L bioreactors. Hence, this study marks a first proof of concept to produce glycolipid surfactants in oxygen-limited BES with an industrially relevant strain.

Authors 5

1. Theresia Desy Askitosari Aachen Institute of Applied Microbiology - iAMB

   RWTH Aachen University

   Affiliation as printed

   Institute of Applied Microbiology—iAMB, Aachen Biology and Biotechnology—ABBt, RWTH Aachen University, 52074 Aachen, Germany

2. Till Tiso Aachen Institute of Applied Microbiology - iAMB

   RWTH Aachen University

   Affiliation as printed

   Institute of Applied Microbiology—iAMB, Aachen Biology and Biotechnology—ABBt, RWTH Aachen University, 52074 Aachen, Germany

3. Falk Harnisch

   Helmholtz Centre for Environmental Research

   Affiliation as printed

   Department of Environmental Microbiology, Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany

4. Lars M. Blank Aachen Institute of Applied Microbiology - iAMB

   RWTH Aachen University

   Affiliation as printed

   Institute of Applied Microbiology—iAMB, Aachen Biology and Biotechnology—ABBt, RWTH Aachen University, 52074 Aachen, Germany

5. Miriam A. Rosenbaum corresponding

   Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie e. V. - Hans-Knöll-Institut (HKI) · Friedrich Schiller University Jena

   Affiliation as printed

   Faculty of Biological Sciences, Friedrich Schiller University Jena, 07745 Jena, Germany

   Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, 07745 Jena, Germany