Nils is a Postdoc in the Criddle Group, funded by the Stanford Natural Gas Initiative. As member of the Center for the Utilization of Biological Engineering in Space (CUBES) he focuses on engineering gas-fermenting microbes towards production of aromatic polyesters as sustainable alternative to petrochemistry-derived plastics.
Before joining Stanford, Nils was task lead of Synthetic Biology with Universities Space Research Association as an Associate Scientist at NASA Ames Research Center. He received his PhD from the University of Queensland in Brisbane, Australia, in Metabolic Engineering working at the Advanced Water Management Centre. Nils holds an engineer’s degree (Dipl. Ing.) in Biochemical Engineering, from the Technical University of Dortmund, Germany.
Doctor of Philosophy, University Of Queensland (2016)
Diplom, Technische Universitat Dortmund (2012)
Production of high-strength bio-polymers from next-generation C1-feedstocks, Stanford University / CUBES (December 17, 2018)
Craig Criddle, (12/17/2018)
Anodic electro-fermentation: Empowering anaerobic production processes via anodic respiration.
In nature as well as in industrial microbiology, all microorganisms need to achieve redox balance. Their redox state and energy conservation highly depend on the availability of a terminal electron acceptor, for example oxygen in aerobic production processes. Under anaerobic conditions in the absence of an electron acceptor, redox balance is achieved via the production of reduced carbon-compounds (fermentation). An alternative strategy to artificially stabilize microbial redox and energy state is the use of anodic electro-fermentation (AEF). This emerging biotechnology empowers respiration under anaerobic conditions using the anode of a bioelectrochemical system as an undepletable terminal electron acceptor. Electrochemical control of redox metabolism and energy conservation via AEF can steer the carbon metabolism towards a product of interest and avoid the need for continuous and cost-inefficient supply of oxygen as well as the production of mixed reduced by-products, as is the case in aerobic production and fermentation processes. The great challenge for AEF is to establish efficient extracellular electron transfer (EET) from the microbe to the anode and link it to central carbon metabolism to enhance the synthesis of a target product. This article reviews the advantages and challenges of AEF, EET mechanisms, microbial energy gain, and discusses the rational choice of substrate-product couple as well as the choice of microbial catalyst. Besides, it discusses the potential of the industrial model-organism Bacillus subtilis as a promising candidate for AEF, which has not been yet considered for such an application. This prospective review contributes to a better understanding of how industrial microbiology can benefit from AEF and analyses key-factors required to successfully implement AEF processes. Overall, this work aims to advance the young research field especially by critically revisiting the fundamental aspects of AEF.
View details for DOI 10.1016/j.biotechadv.2021.107728
View details for PubMedID 33705913
- Editorial: Biotechnological Production and Conversion of Aromatic Compounds and Natural Products. Frontiers in bioengineering and biotechnology 2020; 8: 646
Metabolic engineering of Bacillus subtilis for production of para-aminobenzoic acid - unexpected importance of carbon source is an advantage for space application
2019; 12 (4): 703–14
High-strength polymers, such as aramid fibres, are important materials in space technology. To obtain these materials in remote locations, such as Mars, biological production is of interest. The aromatic polymer precursor para-aminobenzoic acid (pABA) can be derived from the shikimate pathway through metabolic engineering of Bacillus subtilis, an organism suited for space synthetic biology. Our engineering strategy included repair of the defective indole-3-glycerol phosphate synthase (trpC), knockout of one chorismate mutase isozyme (aroH) and overexpression of the aminodeoxychorismate synthase (pabAB) and aminodeoxychorismate lyase (pabC) from the bacteria Corynebacterium callunae and Xenorhabdus bovienii respectively. Further, a fusion-protein enzyme (pabABC) was created for channelling of the carbon flux. Using adaptive evolution, mutants of the production strain, able to metabolize xylose, were created, to explore and compare pABA production capacity from different carbon sources. Rather than the efficiency of the substrate or performance of the biochemical pathway, the product toxicity, which was strongly dependent on the pH, appeared to be the overall limiting factor. The highest titre achieved in shake flasks was 3.22 g l-1 with a carbon yield of 12.4% [C-mol/C-mol] from an amino sugar. This promises suitability of the system for in situ resource utilization (ISRU) in space biotechnology, where feedstocks that can be derived from cyanobacterial cell lysate play a role.
View details for DOI 10.1111/1751-7915.13403
View details for Web of Science ID 000473648300011
View details for PubMedID 30980511
View details for PubMedCentralID PMC6559200
- Metabolic Network Analysis of Microbial Methane Utilization for Biomass Formation and Upgrading to Bio-Fuels FRONTIERS IN ENERGY RESEARCH 2018; 6