Journal of Biotechnology

The development of cost-effective, serum-free media is critical for scalable cultivated meat production. This study used high-throughput screening through a Design of Experiments (DoE) approach to develop an animal-free, serum-free medium (MMM1) specifically for the C2C12 murine myoblasts model cell line with applicability in cultivated meat research including for pet food. Low cost, food-grade inputs such as methylcellulose and spirulina extract resulted in significant cell growth improvements. The optimised MMM1 formulation containing low cost, food-grade inputs, achieved cumulative population doublings comparable to 10% (v/v) fetal bovine serum over four consecutive passages. Furthermore, MMM1 supported scalable cell expansion on commercially available dextran-based microcarriers (Cytodex-3) in both static and agitated conditions in spinner flasks, matching growth rates of serum-based controls. Finally, transitioning to a food-grade DMEM/F12 basal medium maintained cell proliferation equivalent to the pharmaceutical-grade DMEM/F12, but at a significantly lower cost, thus offering a viable strategy to substantially reduce biomanufacturing costs which is a critical challenge in cultivated meat production.

BackgroundRecombinant expression of the SARS-CoV-2 receptor-binding domain (RBD) is essential for vaccine development, serological diagnostics, and mechanistic studies. Primary human fibroblasts offer physiologically relevant protein folding and post-translational modification, yet their short lifespan limits scalable production. We used an immortalized human splenic fibroblast cell line to stably express RBD-sfGFP for longitudinal characterization and downstream studies. MethodsImmortalized human primary splenic fibroblasts were transfected by electroporation with a plasmid encoding SARS-CoV-2 RBD fused to superfolder GFP (sfGFP), with a neomycin resistance cassette (neoR) for G418 selection. Four independent G418-resistant cultures (n=4), designated HPSF-IM-RBD-BHSKPU T1-T4, were established from distinct selection flasks. Based on previous screenings, two cultures (T1, T3) were monitored for 98 days (14 passages, P1-P14); two cultures (T2, T4) were monitored for 42 days (6 passages, P1-P6). RBD-sfGFP expression was assessed by fluorescence microscopy at 7-day intervals. For each timepoint, 2 fields were imaged and analyzed for relative fluorescence intensity (normalized to global maximum = 100%) and mean fluorescence intensity (MFI, normalized to global maximum = 100%). Coefficient of variation (CV), linear regression, and Pearson correlation were calculated. ResultsAll four cultures exhibited robust GFP fluorescence, confirming stable transgene retention. Expression ranking: T1 (93.1% +/- 3.6%) > T3 (89.2% +/- 3.4%) > T2 (84.2% +/- 3.2%) > T4 (79.7% +/- 3.9%). Long-term cultures T1 and T3 retained [~]100% of Day 7 signal at Day 98 (T1: 100.7%; T3: 100.0%). Expression exhibited passage-dependent oscillation rather than progressive silencing. CV increased over time in T1 (1.5% -> 8.5%), indicating growing inter-cellular heterogeneity. A strong positive correlation between fluorescence and MFI (Pearson r = 0.823, p = 7.44 x 10-11) suggested coherent population-level regulation. ConclusionsHPSF-IM-RBD-BHSKPU cells stably retain RBD-sfGFP expression for over 3 months, validating their utility as a recombinant protein production platform. However, oscillatory dynamics and increasing heterogeneity are consistent with position-effect variegation at distinct integration loci. Consequently, early passages (P1-P4) are optimal for applications requiring maximal uniformity. Ultimately, these cells provide a practical tool for RBD production and a valuable model for studying epigenetic regulation of transgene expression in human primary fibroblast backgrounds.

The rapid emergence of SARS-CoV-2 variants that evade neutralizing antibodies underscores the need for next-generation antiviral biologics that combine molecular precision with scalable, cost-effective manufacturing. Computationally designed miniproteins targeting the receptor-binding domain (RBD) of the spike protein offer a compelling alternative to monoclonal antibodies due to their small size, high thermal stability, and compatibility with microbial expression systems. Here we report the end-to-end development and cGMP production of IPD-52520, a de novo antiviral miniprotein, using an optimized E. coli platform. Two miniprotein candidates, a homotrimeric construct (Trimer is referred to as IPD-52520, 17 kDa) and a tandem fusion (Daisy is referred to as IPD-52521, 25 kDa), were evaluated in parallel through systematic optimization of strain selection, media composition, fed-batch fermentation, inclusion-body solubilization, refolding, and chromatographic purification. The Trimer was downselected as the lead molecule based on superior preclinical efficacy, favorable pharmacokinetic properties, and higher volumetric manufacturing yields. The optimized process delivers approximately 2 g/L of purified protein at greater than 90% purity. Scale-up from 5 L to 50 L under cGMP conditions demonstrated excellent batch-to-batch reproducibility across six independent batches, supporting nonclinical and Phase 1 clinical supply. Comprehensive biophysical characterization confirmed a well-folded, predominantly alpha-helical trimer (Tm = 73.4 {degrees}C; polydispersity = 1.005) with an intact primary structure and strong target-binding affinity (KD < 1 pM). Real-time stability studies indicate that the drug substance is stable at 2-8 {degrees}C for at least 12 months, with ongoing stability studies. These results demonstrate the feasibility of translating computationally designed antiviral miniproteins into manufacturable biologics and provide a platform applicable to rapid-response therapeutics against current and future pandemic threats.

Recombinant adeno-associated viruses (rAAVs) have gained increasing importance in gene therapy due to their safe and precise gene delivery. However, certain indications require substantially higher vector doses, pushing manufacturing capacity and cost of goods (COG) to its limits. In this study, we present for the first time a continuous twin-column capture process (CaptureSMB) enabling direct purification of rAAV5 from unprocessed perfusion harvest without prior concentration or processing. This approach differs fundamentally from conventional batch workflows which typically mandate clarification and concentration before affinity capture and offers a novel process integration in viral vector manufacturing. A single-column batch capture process was developed first and subsequently compared to continuous CaptureSMB configurations. Optimized CaptureSMB operation achieved consistent yields over four cycles, with recoveries exceeding batch operation (+ 14.3%) with concomitant higher productivity (+ 11.4%) and reduced buffer consumption (- 79.2%). Critical quality attribute analysis showed lower host cell protein levels and lower residual DNA in early CaptureSMB cycles, while full capsid ratios, thermal stability and transduction efficiency of rAAV5 particles remained unaltered across cycles and process modes. These findings highlight that continuous twin-column CaptureSMB directly from perfusion harvest can not only improve yield and manufacturing efficiency but also maintain and in some respects enhance product quality. This novel strategy provides a promising route to address manufacturing capacity and cost challenges in rAAV gene therapy production.

The successful translation of rationally designed HIV-1 immunogens into effective vaccines requires manufacturing platforms that maintain structural conformity while meeting clinical-grade quality standards. We developed and scaled a robust, cGMP-compliant process for N332-GT5 gp140, a germline-targeting envelope trimer designed to initiate broadly neutralizing antibody responses, which is now undergoing first-in-human evaluation in HVTN144. Starting with a stable CHO cell line developed using Leap-In(R) transposon technology, we established a production clone exhibiting high-titer expression (>200 mg/L) and genetic stability through 60 population doublings. The manufacturing process scaled efficiently from Ambr(R) 250 miniature bioreactors to 200-L single-use systems, delivering consistent product quality across multiple cGMP batches. A streamlined three-step purification strategy--affinity capture, multimodal polishing, and viral clearance- yielded >99% trimeric purity with preserved quaternary structure and native-like antigenicity. Orthogonal LC-MS analyses confirmed site-specific glycan occupancy matching design specifications, while robust viral clearance exceeded 18-log and 11-log reductions for model retroviruses. Clinical material manufactured through this platform has been successfully administered in HVTN144. This work establishes a scalable, reproducible manufacturing paradigm for structurally complex HIV-1 envelope immunogens, advancing the field toward rational vaccine design based on germline-targeting principles.

Lager is the most produced beer style world-wide and makes use of the bottom-fermenting hybrid yeast Saccharomyces pastorianus (S. cerevisiae x S. eubayanus). Previous research showed that flocculation in S. pastorianus, in contrast to the top-fermenting ale yeast S. cerevisiae, is triggered by nitrogen starvation. However, the cellular events leading to flocculation in S. pastorianus are not well characterized. Therefore, we conducted a proteomic screen of S. pastorianus TUM 34/70 and identified the protein kinase Ste20p and protein phosphatase regulatory subunit Ypi1p as higher abundant during flocculation. Overexpression of these genes caused a consistent and strong increase in flocculation rate over the complete duration of beer fermentation. Characterization of Ste20p and Ypi1p via a phospho-proteomics screen showed their targeting of proteins whose S. cerevisiae orthologues are involved in pseudohyphal growth. However, in contrast to this, the overexpression of STE20 and YPI1 led instead to the establishment of a flocculation morphology, giving first-time evidence that S. pastorianus repurposes the pseudohyphal signaling network for this phenotype.

Global demand for platform chemicals and biomaterials urges us to seek sustainable strategies along with waste valorization to produce lactic acid (LA) sustainably. The study has designed a one-pot fermentation strategy by employing in-house produced ligninolytic and saccharifying enzymes on rice straw along with a consortium of hexose and pentose sugar co-fermenting microorganisms. Biological pretreatment with in-house ligninolytic enzyme was selected for the one-pot strategy from a comparison study of chemical and enzymatic pretreatment of rice straw. In this study, simultaneous pretreatment and saccharification of rice straw followed by LA fermentation by Lactobacillus casei- Lactobacillus rhamnosus system (35.58{+/-}0.29 g/L) was found out to be more efficient than Lactobacillus casei-Lactobacillus pentosus system (29.80{+/-}0.92 g/L). Thus, the L. casei- L. rhamnosus system (CR system) was selected and was further statistically optimized by response surface methodology (RSM) to yield 64.96 g/L of LA. The fermentation broth was decolorized and purified by ion exchange chromatography to yield 85.56% pure LA with 84.95% optical purity. The one-pot fermentation strategy has reduced the number of unit operations involved to synthesize LA from rice straw without compromising the yield and purity through a greener route. The use of in-house enzymes and consortium of lactic acid producing bacteria in one-pot presents a strategic approach to sustainable LA production. The biological enroute and the minimum use of chemicals during upstream, fermentation, and downstream processing adds to the carbon credit of the process. HighlightsO_LILactic acid was produced from rice straw using one-pot co-fermentation strategy C_LIO_LIUpstream processing employed in-house enzymes from fungal solid-state fermentation C_LIO_LIThe process addresses the underutilization of pentose sugars after saccharification C_LIO_LIA consortium LAB produced 64.96 g/L LA with 0.855 g/L.h productivity C_LIO_LIDownstream processing yielded LA with 85.56% purity and 84.95% optical purity C_LI

Protein engineering and precision fermentation provide an opportunity to increase the value of food proteins by improving their solubility, stability, functionality, or nutritional composition. Here, we use {beta}-lactoglobulin ({beta}LG) as a model protein to investigate how state-of-the-art computational protein design approaches affect these properties. First, the deep learning-based design tool ProteinMPNN was used to alter up to 20% of {beta}LG residues for increased stability. Second, the physics-based modeling platform PyRosetta was used to find positions in {beta}LG accommodating increased branched-chain amino acid (BCAA) content and up to 10 residues were simultaneously exchanged. Experimental characterisation of ProteinMPNN and stabilised BCAA-enriched variants showed similar secondary structure and oligomeric state as native {beta}LG. ProteinMPNN variants gave increased titers and increased thermal stability up to 15 {degrees}C, and this correlated with changes in the rate of surface pressure in droplet tensiometry. Stabilized BCAA-enriched mutants had altered acid solubility. Correlations between computationally derived biophysical metrics and experimental properties are presented and suggest some predictive power for surface hydrophobicity on protein yield.

PurposeExtracellular vesicles (EVs) are increasingly explored as natural vehicles for drug delivery and gene therapy approaches. However, reproducible yield and scalability of EV production still pose major challenges in the clinical translation of EV-based therapies. In this study, we sought to quantify and characterize EVs released by suspension-cultured HEK293 cells (Expi293F cells) grown in shaker flasks or small-scale bioreactors, to investigate how the culturing environment affects EV production yield. MethodsExpi293F cells were cultivated (N=3) in either shaker flasks or a bioreactor system, and total cell density, viability, and size were monitored. Supernatants were drawn daily post-cell seeding and were analyzed for EV quantity, size, morphology, and CD63 expression. ResultsNo significant differences were observed in terms of total cell density, viability, and cell size between both cultivation settings. However, cultivation of Expi293F cells in the bioreactor environment significantly increased EV yield by 3-fold compared to shaker flask cultivation (p < 0.01). Other parameters such as average nanoparticle size, EV morphology, and CD63 expression remained comparable between both cultivation methods. ConclusionThese results demonstrate that Expi293F-derived EV yield can be increased by culturing cells in a scalable bioreactor system. These findings pave the way towards the production of therapeutic-based EVs in a scalable and reproducible manner suitable for future (pre-)clinical applications.

Calreticulin is an emerging cancer biomarker, but current detection methods rely on expensive monoclonal antibodies that suffer from inefficient protein production, pharmacokinetic challenges and poor tissue penetration. Cal3, a calreticulin-specific nanobody, was constructed by replacing the complimentary determining region 2 (CDR2) of a soluble, clinically validated nanobody with a calreticulin-specific CDR2 isolated from a phage display library. However, the poor solubility and low yield of Cal3 limit its usefulness. In this study, we engineered CALR-Nb02 by adapting the core of Cal3 to a partial consensus framework sequence of stable nanobodies. CALR-Nb02 was purified with a 240-fold higher yield as a predominantly monomeric, soluble protein that exhibits an increased thermal stability and a higher calreticulin binding affinity (KD: 25-50 nM) compared with Cal3. These results reveal a strategy for quickly altering the specificity of a stable nanobody, and provide an improved calreticulin-binding reagent for future diagnostic, imaging, and therapeutic applications.

Recombinant protein purification from E. coli frequently requires screening various affinity tags and variations to optimize yield and purity. However, classical cloning methods are limited in throughput and modularity, which is circumvented by GoldenGate cloning. While GreenGate cloning, a GoldenGate variant, is widely used in plant research, it lacks compatibility with E. coli expression vectors. Here, we introduce a comprehensive, GreenGate-compatible vector toolkit for efficient and versatile assembly of three modules, for N- and C-terminal tagging of a protein of interest into an IPTG-inducible E. coli expression vector. To allow versatility, this toolkit contains diverse affinity tags, with or without HRV3C protease cleavage sites. Moreover, we included plasmids for the homemade low-cost production of this protease. This GreenGate-compatible toolkit allows efficient combinations of different tags and eliminates the need for re-cloning modules between plant and bacterial systems, streamlining the workflow for recombinant protein production, especially in plant research.

The gut microbiome-encoded {beta}-glucuronidase (GUS) enzymes have a significant effect on human physiology through their deglucuronidation activity on endogenous and exogenous glucuronides. GUS activity also significantly influences the pharmacokinetics, efficacy and toxicity of various drugs including chemotherapeutic drugs. Given their crucial role in drug metabolism, GUS enzymes have emerged as promising targets for therapeutic intervention. Here, we have identified and characterized 79 unique GUS enzymes through a structure-guided approach. Structural modelling of these GUS enzymes revealed a conserved core and active-site residues with significant variations in the number and nature of the C-terminal domains. A new classification system based on the number and type of additional C-terminal domains is presented for the GUS proteins. Further, GUS enzymes have been categorized into different loop categories linked to their substrate preferences. The relationship between domain architecture and loop-type is explored by sequence similarity network analysis. We could successfully express, purify and validate GUS processing capability of a panel of identified GUS proteins. The nature of oligomer organization has been deciphered by SEC and DLS studies. Further, we have identified additional GUS enzymes capable of processing SN-38G, glucuronidated form of anticancer drug, irinotecan. These newly identified GUS enzymes will offer valuable insights into gut microbial GUS diversity and their role in understanding the population-specific drug-induced adverse effects on human health.

In liquid fermentation of filamentous fungi such as Aspergillus oryzae, increased broth viscosity and biomass adhesion to bioreactor surfaces remain major challenges. We previously developed a hyphal dispersion mutant lacking two hyphal adhesion factors, namely cell wall -1,3-glucan (AG) and biofilm galactosaminogalactan (GAG) (AG{Delta}-GAG{Delta} strain). The culture broth of the AG{Delta}-GAG{Delta} strain has low viscosity, which improves mixing and enzyme production. However, mycelia still extensively attach to bioreactor walls and downstream equipment, which impairs mixing and reduces product recovery. The hydrophobin RolA, a surface-active protein of A. oryzae, densely coats conidia and hyphae and contributes to cell surface hydrophobicity. In this study, we disrupted the rolA gene in AG{Delta}-GAG{Delta} (AG{Delta}-GAG{Delta}-{Delta}rolA strain) and evaluated the effects of this disruption on hyphal adhesion to the walls of culture vessels, enzyme production, and bioreactor performance. At the flask scale, the adhesion to glass surfaces was significantly reduced and recombinant enzyme activity was increased by 10%. Improved culture recovery at the end of fermentation further increased total enzyme yield. In a lab-scale stirred-tank bioreactor, both growth and enzyme production were increased. Scaling-up to a 200-L bioreactor showed reduced agitation power consumption while improving hydrodynamic properties. Fermentation of AG{Delta}-GAG{Delta}-{Delta}rolA was successfully scaled up to a 3000-L bioreactor; consistent enzyme activity and improved flow circulation in the bioreactors were confirmed by computational fluid dynamics analysis. Overall, the AG{Delta}-GAG{Delta}-{Delta}rolA strain has increased enzyme production and scalability, supporting its suitability for industrial applications.

This study investigates electro-fermentation candida Tropicalis SY005 to address fermentation kinetics limitation during grape must fermentation. In comparison with non-stimulated control sample, EF substantially enhanced sugar depletion, TSS drop by day 3 and generated a strongly reduced state (ORP -100 to -143mV). The oxidation-reduction shift enhanced cellular NAD+ regeneration, reducing total fermentation duration from 264 h to 72 h. GC-MS analysis showed pronounced major characteristic volatile compound confirming substantial metabolic pathway shifts in flavor of glycolytic flux. Moreover moderate electric field promoted cellular membrane electropermeabilization substantially promoting bioactive extraction.

The trend towards concentrated animal feeding operations (CAFOs) has served to concentrate not only livestock animals but the waste they produce to comparatively smaller areas. The point-source nature of this waste is an opportunity for the recovery and valorization of the nitrogen therein. Such a process would be viable on small to intermediate scales and require minimal inputs at the CAFO. In this study, we demonstrate the potential of the biopolymer cyanophycin to serve as a medium for manure-nitrogen recovery. In the first step, genetically modified strains of Escherichia coli produce intracellular cyanophycin from mock manure hydrolysates. Next, cyanophycin is recovered from microbial biomass via acid solubilization and base precipitation using electrochemically generated acids and bases. Finally, to improve both the yield and recoverable fraction of cyanophycin produced, we leverage the tunability of our genetically engineered system to probe the impacts of cyanophycin synthetase solubility, N-domain activity, and cyanophycin molecular weight on cyanophycin recoverability. Collectively, this work serves as a proof of concept for nitrogen recovery from agricultural waste, aligning with global sustainability initiatives.

Bacterial microcompartments (MCPs) are versatile proteinaceous organelles that compartmentalize metabolic pathways, offering promising scaffolds for synthetic biology and metabolic engineering. However, designing customized nanobioreactors requires distinguishing structurally indispensable shell proteins from those that can be modified or deleted to tune shell permeability without disrupting core organelle assembly. In this study, we performed a systematic biophysical and metabolic characterization of the hexameric shell protein PduU to evaluate its potential as a modular platform for synthetic organelle engineering. We tested whether deleting pduU or selectively truncating its N-terminal {beta}-barrel domain preserves shell assembly, metabolite flux, and intermediate confinement. Our results demonstrate that PduU modifications alter shell permeability while fully maintaining organelle structural integrity, monodispersity, and electrostatic colloidal stability. Crucially, this modulation in permeability redirects internal metabolic flux toward the energy-generating propionate pathway, resulting in elevated cell biomass and significantly increased yields of propionate, an economically vital industrial platform chemical. By establishing that PduU is a non-essential structural component whose modification tunes small-molecule flux, this work highlights PduU as a flexible locus for shell engineering, providing a scalable strategy for biomanufacturing of high-value bio-based products in tailor-made MCP nanobioreactors.

The increasing world population necessitates new sustainable nutrient sources, making microalgae like Chlorella sorokiniana interesting due to its rich nutrient profile and sustainable cultivation methods. With genetic optimization tools like CRISPR/Cas9, microalgae as a nutrient source can be improved even further. However, degradation of the rigid cell wall of microalgae, and thereby developing protoplasts, is often necessary prior to transformation, but monitoring protoplast development in spherical, single-celled organisms like C. sorokiniana is challenging using bright-field microscopy. Carbotrace 480 and 630 were tested as fluorescent markers of the cell wall of a C. sorokiniana mutant for protoplast detection, and Carbotrace 480 was successfully used to distinguish protoplast from normal cells in a cell suspension. The enzymes Driselase, Glucanex, Snailase, and Saczyme were tested in different combinations to degrade the cell wall of the mutant, with Snailase as the most effective yielding ~60 % protoplasts. This study provides a quick and easy tool for monitoring protoplast development in the microalgae C. sorokiniana, the first step to improve C. sorokiniana as a sustainable nutrient source using genetic optimization tools like CRISPR/Cas9.

The filamentous cyanobacterium Nostoc punctiforme is a key model organism used to study several aspects of cyanobacterial biology, including development, nitrogen-fixing symbioses with plants, and secondary metabolites, among others. While N. punctiforme is amenable to genetic manipulation, traditional approaches for the generation of mutant strains using homologous recombination are slow, requiring prolonged outgrowth under antibiotic selection to ensure isogenic mutant populations. CRISPR-based genome editing using Cpf1 (Cas12a) was recently shown to be an effective means of rapid generation of isogenic mutants in several cyanobacteria. In this study, Cpf1-based genome editing tools were developed for N. punctiforme. A total of 19 unmarked, in-frame deletion mutants were successfully constructed using Cpf1-targeted cleavage along with homology directed repair (HDR). The length of the homology arms (HAs) on the homologous repair template (HRT) used for HDR was found to be a critical factor for successful deletion of target genes, with some requiring up to 4 kb HAs to acquire mutant exconjugants. A strategy for allelic replacement was also developed by introducing an exogenous target site in place of the deleted genes, which could subsequently be targeted for cleavage and repaired with an HRT containing altered alleles of the genes of interest. Additionally, a single-step cloning strategy was devised, allowing for rapid assembly of editing plasmids, and improved conjugation protocols for genetic transfer from E. coli to N. punctiforme were implemented. Collectively, these tools and protocols should enhance the pace and ease of conducting genetic studies in this important model cyanobacterium.

Past few decades witnessed a boom in pharmaceutical and bioproduct industry with the help of bioprocess technology. Industrially important bioproducts can be produced in large scale for commercialization with the help of fermenters. Here in, pharmaceutically valuable bioproduct melanin, synthesized from Pseudomonas stutzeri strain BTC109 by using two different sized bioreactors. Under controlled conditions the bacteria were allowed to synthesis melanin nanoparticles. The important parameters to be monitored here are pH, dissolved oxygen, agitation, aeration, melanin production and cell biomass concentration. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=163 SRC="FIGDIR/small/737634v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@d92fe5org.highwire.dtl.DTLVardef@d76c07org.highwire.dtl.DTLVardef@f5516forg.highwire.dtl.DTLVardef@1b5864b_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIPharmaceutical and bioproduct development industries witnessed a shoot up due to bioprocess technology. C_LIO_LIIndustrially important bioproduct like melanin can be produced in large scale with the help of industrial fermentation technology. C_LIO_LIThe product thus obtained was found to be nano sized and it can be commercialized. C_LI

Iron is a key micronutrient that constrains microbial growth and productivity in many aquatic and terrestrial environments due to its limited bioavailability. Microorganisms evolved sophisticated acquisition strategies, including the production of siderophores, high-affinity iron-chelating molecules that facilitate iron solubilisation and uptake. Cyanobacteria, photosynthetic prokaryotes and major contributors to global primary production, also depend on iron as a cofactor to their core metabolic enzymes. However, very few cyanobacterial siderophores were described so far, and cyanobacteria remain an underxplored source of possibly novel siderophores. Here we report a novel cyanobacterial siderophore, cyanochelin C, that employs two {beta}-hydroxyaspartate residues for iron chelation. We provide extensive nuclear magnetic resonance (NMR) and mass spectrometry (MS) evidence on the molecular structure and identify the corresponding biosynthetic gene cluster (BGC). Bioinformatic analysis of the BGC further revealed the presence of an acylase CcsQ clustering with a broader cyanobacteria-specific family of acylases associated with predicted siderophore-encoding BGCs. Discovery of cyanochelin C and its deacylation by CcsQ expands the known structural diversity of cyanobacterial siderophores and improves the understanding of important enzymatic reactions.