Biology subjects

Nikel, P. I.

Publications and source records attributed to Nikel, P. I..

At least 19 recordsLinked to original sources

bioRxiv2026

Adaptive laboratory evolution rewires Pseudomonas putida for resource-efficient acetate assimilation

Acetate is an attractive renewable two-carbon substrate for microbial biotechnology, but its toxicity limits growth and carbon-use efficiency at process-relevant concentrations. Here, we used adaptive laboratory evolution to improve acetate tolerance in a genome-reduced strain of Pseudomonas putida and combined whole-genome sequencing, reverse engineering, transcriptomics, proteomics, and 13C-acetate fluxomics to resolve the underlying adaptation mechanisms. Evolution under increasing acetate concentrations selected recurrent mutations in gacA and fabB, which encode a global response regulator and a fatty acid biosynthesis enzyme, respectively. Reverse engineering of these mutations recovered most of the evolved phenotype, including shorter lag phase and substantially higher biomass yield from acetate. Multi-omic analyses showed repression of type VI secretion systems, carbohydrate storage functions, fatty acid metabolism, and oxidative stress-associated proteins, indicating resource reallocation away from costly stress and non-essential programs. Fluxomics further revealed reduced EDEMP cycling and increased glyoxylate shunt flux, consistent with improved acetate-carbon retention in biomass. These results establish acetate tolerance in P. putida as a resource-efficiency phenotype and identify gacA and fabB as actionable targets for acetate-based bioproduction.

synthetic biology↗

bioRxiv2026

Improving acetate metabolism of Pseudomonas putida KT2440 by evolutionary and rational engineering

Acetate is a promising carbon source for microbial biotechnology as it can be produced sustainably from lignocellulosic biomass or C1 gases. Since acetate is directly activated to acetyl-CoA, it is especially suitable for producing acetyl-CoA-derived products, showcased here with the production of 3-(3-hydroxyalkanoyloxy) alkanoic acids (HAAs). P. putida KT2440 can natively metabolize acetate, but the weak acid has also inhibitory effects on microbial growth. We present an in-depth study on the physiology of P. putida KT2440 using acetate as carbon and energy source and evaluate acetate as feedstock for the biosynthesis of HAAs. Initially, a rational engineering approach to overexpress acetyl-CoA synthetase for acetate activation resulted in an improved growth rate of 16% and reduced lag phase by six hours. To further increase the performance of P. putida KT2440 on acetate, adaptive laboratory evolution was performed. This resulted in an improvement in the growth rate from 0.4 h-1 to 0.6 h-1 and enabled growth on up to 12.5 g L-1 acetate with a shortened lag phase compared to the wild type. Whole-genome sequencing revealed mutations in proteins involved in gene expression regulation and signal transduction. This evolutionary engineering approach informed the deletions of gacS and crc, which resulted in a reduction in the lag phase from seven hours to one hour and an improvement of the growth rate by 25 %, matching the growth properties of the evolved clones. Using the evolved strains for the production of HAAs resulted in faster biomass and product formation with product titers reaching up to 94 % of that of the wild type. In conclusion, we identified mechanisms in the acetate metabolism of P. putida KT2440 and improved the growth performance of the strain by rational and evolutionary engineering, demonstrating the potential of the promising, but challenging 3rd generation feedstock acetate.

microbiology↗

bioRxiv2026

A rapid HPLC-based method to determine NAD(P)(H) and NMN redox cofactor concentrations and ratios in microbes

Redox cofactors are a key part of cellular physiology as they are involved in most metabolic pathways, and their ratios are linked to cellular robustness. However, measuring their levels in cells remains a challenge. Here, we describe a novel method to rapidly measure NAD(H), NADP(H) and nicotinamide mononucleotide (NMN) levels and their oxidized/reduced ratios using an HPLC connected to a fluorescence detector. By extensively characterizing this method and benchmarking it against the classical iodonitrotetrazolium (INT) assay, we show that this method results in accurate and reproducible measurements of NAD+, NADP+ and NMN levels in bacteria. We further demonstrate that this method can be used to determine intracellular NADH and NADPH concentrations and ratios of nicotinamide nucleotide cofactors in engineered Escherichia coli strains, as well as other bacterial species such as Pseudomonas putida.

biochemistry↗

bioRxiv2026

Seven mutations unlock strict synthetic methylotrophy in engineered Pseudomonas putida

Methanol is a reduced, soluble one-carbon (C1) feedstock for sustainable bioproduction, but converting this potential into robust microbial growth remains difficult. Several synthetic C1 assimilation routes depend on autocatalytic cycles, whose operation requires coordinated control of redox balance, toxic intermediates, substrate regeneration, and host regulation. Here, we implemented the serine-threonine cycle (STC) in the soil bacterium Pseudomonas putida and used growth-coupled selection with adaptive laboratory evolution (ALE) to transition from mixotrophic C1 incorporation to strict methylotrophy. The evolved strain grew with methanol as the sole carbon and energy source under atmospheric CO2 with a doubling time of ca. 40 h. Whole-genome sequencing, reverse genetics, biosensors, isotope labelling, and comparative RNA sequencing showed that evolution repeatedly targeted native pyrroloquinoline quinone (PQQ)-dependent methanol oxidation, membrane-bound transhydrogenase activity, glycine regeneration, STC enzyme balance, and global regulatory nodes. Additional ALE under glycine-methanol co-feeding increased growth rates and exposed further targets for improving cycle flux. These results establish P. putida as a chassis for strict synthetic methylotrophy and define actionable engineering routes toward C1 biomanufacturing. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=63 SRC="FIGDIR/small/739708v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1642d2dorg.highwire.dtl.DTLVardef@1d203d1org.highwire.dtl.DTLVardef@f8a5d7org.highwire.dtl.DTLVardef@4fe272_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2026

Multiparameter optimization extends the lifetime of cell-free protein synthesis in a high-throughput format

Cell-free protein synthesis (CFPS) is a powerful platform for synthetic biology, yet the factors governing reaction longevity remain poorly understood despite their importance for high-throughput applications. Here, the three principal determinants of CFPS performance--DNA template design, reaction composition, and lysate genotype--were systematically optimized to extend reaction lifetime in a 384-well plate format. Different energy regeneration systems were evaluated through real-time pH monitoring and metabolomic analyses to identify the metabolic constraints limiting prolonged protein synthesis. Lysates prepared from engineered Escherichia coli BL21(DE3) strains were further examined to assess the contributions of DNA, RNA, and amino acid stabilization. Systematic optimization of amino acid, nucleoside triphosphate, polyethylene glycol, and lysate concentrations identified DNA template stability and amino acid preservation as the primary factors sustaining CFPS activity. Combining these improvements yielded reactions that remained productive for >14 h and produced 567 {+/-} 64 g mL-1 active deGFP. These findings establish practical strategies for extending CFPS lifetime and improving high-throughput cell-free platforms.

molecular biology↗

bioRxiv2026

A microbial growth-coupled platform for in vivo interrogation of Rubisco oxygenase activity

Rubisco catalyzes the primary CO2-fixing reaction of the biosphere, yet its competing oxygenation reaction reduces net global carbon fixation and has resisted direct exploration in living cells. Here, we engineer an auxotrophic Escherichia coli strain in which 2-phosphoglycolate, the direct product of Rubisco oxygenation, becomes essential for growth, making bacterial fitness a quantitative proxy for oxygenation flux in vivo. This provides direct access to catalytic selectivity, something previously inaccessible to carboxylation-coupled assays. The platform enables screening of phylogenetically diverse Form II Rubisco and phosphoribulokinase (Prk) variants circumventing protein purification and extensive in vitro characterization. Adaptive laboratory evolution under oxygenation-selective pressure identified two mutations: Rubisco M115I genetically rebalances the in vivo carboxylation/oxygenation trade-off (resulting in 6-fold reduction in kcat,C), while Prk N216T improves overall flux without altering selectivity. This platform makes Rubiscos least-studied catalytic function selectable and evolvable in vivo, opening the carboxylation/oxygenation trade-off to systematic genetic dissection and engineering.

synthetic biology↗

bioRxiv2026

Automated mini-bioreactors reveal the temporal dynamics and multi-omics responses of CRISPRi knockdowns in Pseudomonas putida

Characterizing CRISPR interference (CRISPRi) phenotypes presents a fundamental temporal challenge: pre-existing overabundance of target proteins can mask early silencing, requiring extended growth for dilution, yet prolonged repression rapidly selects for escaper mutants. To resolve this, we integrated a tightly regulated CRISPRi system in Pseudomonas putida with an automated mini bioreactor platform operating in turbidostat mode. By maintaining continuous exponential growth, we mapped the exact temporal dynamics of essential gene silencing. We identified a critical observation window between 17 and 27 hours (7-9.5 cell doublings) where repression exerts its maximum physiological impact, directly preceding population takeover by target-site mutated escapers. Applying this workflow to the arginine biosynthesis pathway, multi-omics profiling disentangled transient physiological buffering from long-term mutational events, revealing that argH and argG knockdowns trigger highly diverse metabolomic perturbations. This scalable framework overcomes batch culture limitations, ensuring precise temporal control for accurate phenotypic characterization and reliable functional genomics. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/709552v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@c6795dorg.highwire.dtl.DTLVardef@49f52dorg.highwire.dtl.DTLVardef@17f5d80org.highwire.dtl.DTLVardef@d3bbca_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2026

Computational pipeline reveals nature's untapped reservoir of halogenating enzymes

Microbial halogenated natural products (hNPs) hold ecological, agricultural, and biomedical relevance. The hNP-producing potential of the organism can be assessed by the precise prediction of biosynthetic enzymes, yet the detailed annotations of halogenases are often missing from genomic and metagenomic data. We created a manually curated database (https://halogenases.secondarymetabolites.org/) containing information on the halide-specificity, role, and position of verified catalytic residues and results of the mutagenesis studies of more than 120 experimentally validated or in silico inferred halogenases. The collection of experimental data supports a computational pipeline that allows the family-, substrate-, and halide-scope-level annotation of halogenating enzymes by relying on catalytic residues, conserved motifs, and profile Hidden Markov Models (pHMMs). Our analysis with sequence similarity networks (SSNs) highlighted several underexplored clusters in the UniRef50 database. Such finding was a halogenase from Rhodopirellula baltica (RhobaVHPO) previously labelled as a hypothetical chloroperoxidase, which clustered apart from the known chloroperoxidases and bromoperoxidases, but accepted chloride and preferred bromide. Our database and workflow provide extensive and scalable solutions for the systematic and precise annotation of halogenating enzymes in genomic and metagenomic data. The in-depth categorization of halogenases will improve the chemical structure prediction of microbial hNPs, supporting ecological assessments and natural product discovery. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/700248v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@ebae51org.highwire.dtl.DTLVardef@10188f0org.highwire.dtl.DTLVardef@1c55684org.highwire.dtl.DTLVardef@b311bd_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2025

Integrated control of redox and energy metabolism by the membrane-bound and soluble transhydrogenases of Pseudomonas putida across metabolic regimes

Redox homeostasis is central to microbial physiology and stress adaptation, yet the functional roles of transhydrogenases remain poorly understood beyond a few organisms. In this study, we systematically explored how Pseudomonas putida, a model soil bacterium, integrates two distinct transhydrogenases (membrane-bound PntAB and soluble SthA) into a flexible and reversible redox-balancing system that supports metabolic robustness across diverse metabolic regimes. While single deletions of either enzyme had minimal impact on the overall fitness, the double {Delta}pntAB {Delta}sthA mutant exhibited growth defects, disrupted energy charge, and redox imbalance. Unexpectedly, SthA proved essential for acetate-dependent growth, a phenotype traced to a transcriptional regulator involved in glyoxylate metabolism. Transhydrogenases also mediated tolerance to formate, a key one-carbon (C1) substrate for biotechnology, by channeling reducing equivalents released during feedstock oxidation. Synergistic activity with native formate dehydrogenases enabled redox buffering, even under stressful conditions. Functional complementation with native and engineered NAD+- or NADP+-dependent dehydrogenases validated SthA as the main sink for excess NADH. Comparative genomics linked transhydrogenase gene neighborhoods to stress and membrane processes, highlighting their evolutionary significance. These findings redefine transhydrogenases as dynamic regulators of redox metabolism, not passive cofactor shuttles. Furthermore, this work positions P. putida as a prime host for redox-intensive applications, informing design principles for C1-based metabolic engineering. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/686620v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@17c0e06org.highwire.dtl.DTLVardef@17cd094org.highwire.dtl.DTLVardef@161b5b9org.highwire.dtl.DTLVardef@1e1897e_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2025

Adaptive evolution of Pseudomonas putida in the presence of fluoride exposes moonlighting transporter functions

Fluoride (F-), the anionic form of fluorine and the 13th most abundant element in Earths crust, is toxic to most organisms above relatively low threshold concentrations. Environmental bacteria often tolerate elevated fluoride levels, but the only known resistance mechanism so far involves CrcB-mediated efflux. In the environmental bacterium Pseudomonas putida, CrcB export is the primary defense against fluoride stress. Yet, spontaneous NaF-tolerant mutants emerge even without this transporter, suggesting the existence of additional pathways. To uncover these mechanisms, we performed a genome-wide screen of over 141,000 transposon mutants. We identified PP_3125, a Cro/cI-type transcriptional regulator, as essential for high fluoride tolerance in a {Delta}crcB background. Transcriptomic and proteomic analyses revealed PP_3125-regulated genes, including the benzoate transporter BenE-I, which contributes directly to fluoride tolerance. These findings demonstrate that bacterial transporters can acquire moonlighting functions beyond their canonical roles and reveal previously unrecognized fluoride tolerance strategies in P. putida. Together, our results expand understanding of microbial adaptation to toxic ions and provide new targets for engineering stress-resilient strains for environmental and industrial applications. IMPORTANCEOur work identifies a new fluoride tolerance mechanism in Pseudomonas putida that functions independently of the well-characterized CrcB efflux system. We show that inactivation of transcriptional regulator, PP_3125, activates a transporter with an unexpected moonlighting role in fluoride tolerance, highlighting how bacteria can repurpose existing functions to survive environmental stress. This discovery deepens our understanding of microbial stress responses and suggests strategies to engineer robust microbial strains capable of thriving in fluoride-contaminated settings. Such strains could be valuable for bioremediation, sustainable bioprocessing, and other biotechnological applications where fluoride exposure limits microbial performance.

microbiology↗

bioRxiv2025

Mechanism-Guided Engineering of Fluorinase Unlocks EfficientNucleophilic Biofluorination

The fluorinase enzyme, the only known biocatalyst forming stable carbon-fluorine bonds, operates with extremely low efficiency, catalyzing one reaction every 2-12 minutes. This severely limits its utility for sustainable biofluorination, and its sluggish activity remains poorly understood. We suppressed its aggregation through directed mutagenesis and elucidated the kinetic mechanism using a novel mathematical framework that fits complex kinetic and oligomerization data. This analysis revealed that >80% of enzyme molecules are inactive under standard conditions due to two dead-end pathways. The designed W50F+A279R mutant preferentially formed hexamers and displayed enhanced catalytic efficiency in this oligomeric state. When coupled with mechanism-based optimization of the reaction medium, including enzymatic removal of the inhibitory product, the catalytic turnover rate reached 12.5 {+/-} 2.1 min-{superscript 1}, representing [~]60-fold increase compared with previously reported turnover rates of the wild-type enzyme. Our work provides a mechanistic blueprint for fluorinase enhancement and a generalizable mathematical framework for analyzing kinetics of multimeric enzymes.

biochemistry↗

bioRxiv2025

Co-Substrate Free Valorisation of Lignin Monomers by Assimilation of C1 and C2 By-Products

Lignin is an underutilised global resource with significant potential for the production of chemicals that are currently derived from fossil resources. However, biotechnological lignin valorisation faces various challenges including its recalcitrance and the toxicity of aromatic intermediates, products, and by-products like formaldehyde. While biochemical production from lignin-derived monomers has been demonstrated by disrupting native lignin degradation pathways, this approach required co-feeding additional carbon sources such as glucose for growth. This dependence on additional carbon sources can create competition with the food industry and undermine the economic sustainability of the bioprocess. Here, we report growth of a protocatechuate production strain of Pseudomonas putida EM42 on the by-products from p-coumarate and ferulate valorisation, achieving carbon efficiencies of up to 78 %. Additional flux balance analysis identified C1 assimilation pathways, including two novel pathways, beneficial for the growth on the formaldehyde by-product from ferulate degradation leading to improved carbon utilisation. This study demonstrates how by-product utilisation from lignin conversion can eliminate the need for co-feeding additional carbon sources, thereby potentially improving the efficiency of lignin valorisation.

bioengineering↗

bioRxiv2025

Systematic engineering of synthetic serine cycles in Pseudomonas putida uncovers emergent topologies for methanol assimilation

The urgent need for a circular carbon economy has driven research into sustainable substrates, including one-carbon (C1) compounds. The non-pathogenic soil bacterium Pseudomonas putida is a promising host for exploring synthetic methylotrophy due to its versatile metabolism. In this work, we implemented synthetic serine cycle variants in P. putida for methanol assimilation combining modular engineering and growth-coupled selection, whereby methanol assimilation supported biosynthesis of the essential amino acid serine. The serine cycle forms acetyl-coenzyme A from C1 molecules without carbon loss but has bottlenecks that hinder engineering efforts. We adopted three synthetic variants (serine-threonine cycle, homoserine cycle, and modified serine cycle) that yield serine in a methanol-dependent fashion to overcome these challenges. By dividing these metabolic designs into functional modules, we systematically compared their performance for implementation in vivo. Additionally, we harnessed native pyrroloquinoline quinone-dependent dehydrogenases for engineering methylotrophy. Recursive rewiring of synthetic and native activities revealed novel metabolic topologies for methanol utilization, termed enhanced serine-threonine cycle, providing a blueprint for engineering C1 assimilation in non-model heterotrophic bacteria. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC="FIGDIR/small/638773v1_ufig1.gif" ALT="Figure 1"> View larger version (79K): org.highwire.dtl.DTLVardef@1bfccd0org.highwire.dtl.DTLVardef@11f77deorg.highwire.dtl.DTLVardef@f6a904org.highwire.dtl.DTLVardef@1d24a34_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2025

Genetic dissection of cyclic di-GMP signaling in Pseudomonas aeruginosa via diguanylate cyclase disruption

The second messenger bis-(3'[->]5')-cyclic dimeric guanosine monophosphate (c-di-GMP) governs adaptive responses in the opportunistic pathogen Pseudomonas aeruginosa, including biofilm formation and the transition from acute to chronic infections. Understanding the intricate c-di-GMP signaling network remains challenging due to the overlapping activities of numerous diguanylate cyclases (DGCs). In this study, we employed a CRISPR-based multiplex genome-editing tool to disrupt all 32 GGDEF domain-containing proteins (GCPs) implicated in c-di-GMP signaling in P. aeruginosa UCBPP-PA14. Phenotypic and physiological analyses revealed that the resulting mutant was unable to form biofilms and had attenuated virulence. Residual c-di-GMP levels were still detected despite the extensive GCP disruption, underscoring the robustness of this regulatory network. Taken together, these findings provide insights into the complex c-di-GMP metabolism and showcase the importance of functional overlapping in bacterial signaling. Moreover, our design overcomes the native redundancy in c-di-GMP synthesis, providing a framework to dissect individual DGC functions and paving the way for targeted strategies to address bacterial adaptation and pathogenesis.

microbiology↗

bioRxiv2024

Streamlined and efficient genome editing in Cupriavidus necator H16 using an optimised SIBR-Cas system

Cupriavidus necator H16 is a promising microbial platform strain for CO2 valorisation. While C. necator is amenable to genome editing, existing tools are often inefficient or rely on lengthy protocols, hindering its rapid transition to industrial applications. In this study, we simplified and accelerated the genome editing pipeline for C. necator by harnessing the Self-splicing Intron-Based Riboswitch (SIBR) system. We used SIBR to tightly control and delay Cas9-based counterselection, achieving >80% editing efficiency at two genomic loci within 48 hours after electroporation. To further increase the versatility of the genome editing toolbox, we upgraded SIBR to SIBR2.0 and used it to regulate the expression of Cas12a. SIBR2.0-Cas12a could mediate gene deletion in C. necator with [~]70% editing efficiency. Overall, we streamlined the genome editing pipeline for C. necator, facilitating its potential role in the transition to a bio-based economy.

bioengineering↗

bioRxiv2024

CIFR (Clone-Integrate-Flip-out-Repeat): a toolset for iterative genome and pathway engineering of Gram-negative bacteria

Advances in genome engineering enable precise and customizable modifications of bacterial species. Toolsets for metabolic engineering that exhibit broad-host compatibility are particularly valued owing to their portability. Tn5 transposon vectors have been widely used to establish random integrations of desired DNA sequences into bacterial genomes. However, the iteration of the procedure remains challenging because of the limited availability of selection markers. Here, we present CIFR, a mini-Tn5 integration system for iterative genome engineering. The pCIFR vectors incorporate attP and attB sites flanking an antibiotic resistance marker used to select for the insertion. Subsequent removal of these antibiotic determinants is facilitated by the Bxb1 integrase, and a user-friendly counter-selection marker, both encoded in auxiliary plasmids. Hence, CIFR delivers engineered strains harboring stable DNA insertions and free of any antibiotic resistance cassette, allowing for the reusability of the tool. The system was validated in Pseudomonas putida, Escherichia coli, and Cupriavidus necator, underscoring its portability across diverse industrially-relevant hosts. The CIFR toolbox was calibrated through combinatorial integrations of chromoprotein genes in P. putida, generating strains displaying a diverse color palette. Next, we introduced a carotenoid biosynthesis pathway in P. putida in a two-step engineering process, showcasing the potential of the tool for pathway balancing. The broad utility of the toolbox expands the synthetic biology toolkit for metabolic engineering, allowing for the construction of complex phenotypes, while opening new possibilities in bacterial genetic manipulations.

synthetic biology↗

bioRxiv2024

Growth-coupled microbial biosynthesis of the animal pigment xanthommatin

The mining of genomes across life has unearthed a bounty of biosynthetic potential to diverse molecules key to a biobased future. While the heterologous expression of metabolic pathways has achieved broad success, most approaches suffer a similar fate in low initial production levels that require extensive, resource-heavy iterative strain engineering refinement. Herein we introduce a growth-coupled biosynthetic (GrowBio) strategy that irrevocably connects microbial growth with specialized compound production. We demonstrate the plug-and-play versatility of GrowBio in the production of the structurally complex animal biopigment xanthommatin, a color-changing ommochrome with material and cosmetic potential. Xanthommatin biosynthesis directly fuels growth of a newly designed Pseudomonas putida 5,10-methylenetetrahydrofolate auxotroph (PUMA). Aided by genome-scale metabolic modeling, PUMA was designed and built to be controlled by endogenous formate co-produced as a coupled biosynthetic byproduct in the multistep conversion of tryptophan to xanthommatin. Adaptive laboratory evolution was utilized to streamline xanthommatins gram-scale bioproduction via growth rate selection, establishing GrowBio as a promising biotechnological approach for establishing and optimizing the microbial production of value-added molecules.

synthetic biology↗

bioRxiv2024

Expanding the biotechnological scope of metabolic sensors through computation-aided designs

Metabolic sensors are microbial strains modified so that biomass formation correlates with the availability of specific metabolites. These sensors are essential for bioengineering (e.g. in growth-coupled designs) but creating them is often a time-consuming and low-throughput process that can potentially be streamlined by in silico analysis. Here, we present the systematic workflow of designing, implementing, and testing versatile Escherichia coli metabolic sensor strains. Glyoxylate, a key metabolite in (synthetic) CO2 fixation and carbon-conserving pathways, served as the test molecule. Through iterative screening of a compact metabolic model, we identified non-trivial growth-coupled designs that resulted in six metabolic sensors with a wide sensitivity range for glyoxylate, spanning three orders of magnitude in detected concentrations. We further adapted these E. coli strains for sensing glycolate and demonstrated their utility in both pathway engineering (testing a key metabolic module via glyoxylate) and applications in environmental monitoring (quantifying glycolate produced by photosynthetic microalgae). The versatility and ease of implementation of this workflow make it suitable for designing and building multiple metabolic sensors for diverse biotechnological applications. TeaserA streamlined workflow enables the rapid design of versatile E. coli metabolic sensors for detecting key metabolites in bioengineering and monitoring.

synthetic biology↗