scholarly journals Towards a 'chassis' for bacterial magnetosome biosynthesis: genome streamlining of Magnetospirillum gryphiswaldense by multiple deletions

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Theresa Zwiener ◽  
Marina Dziuba ◽  
Frank Mickoleit ◽  
Christian Rückert ◽  
Tobias Busche ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Large Scale ◽  
Gene Clusters ◽  
Genome Reduction ◽  
Cell Factory ◽  
Wild Type ◽  
Biosynthetic Gene Clusters ◽  
Microbial Cell Factory ◽  
Magnetospirillum Gryphiswaldense ◽  
Large Gene

Abstract Background Because of its tractability and straightforward cultivation, the magnetic bacterium Magnetospirillum gryphiswaldense has emerged as a model for the analysis of magnetosome biosynthesis and bioproduction. However, its future use as platform for synthetic biology and biotechnology will require methods for large-scale genome editing and streamlining. Results We established an approach for combinatory genome reduction and generated a library of strains in which up to 16 regions including large gene clusters, mobile genetic elements and phage-related genes were sequentially removed, equivalent to ~ 227.6 kb and nearly 5.5% of the genome. Finally, the fragmented genomic magnetosome island was replaced by a compact cassette comprising all key magnetosome biosynthetic gene clusters. The prospective 'chassis' revealed wild type-like cell growth and magnetosome biosynthesis under optimal conditions, as well as slightly improved resilience and increased genetic stability. Conclusion We provide first proof-of-principle for the feasibility of multiple genome reduction and large-scale engineering of magnetotactic bacteria. The library of deletions will be valuable for turning M. gryphiswaldense into a microbial cell factory for synthetic biology and production of magnetic nanoparticles.

scholarly journals Changes in Oxygen Availability during Glucose-Limited Chemostat Cultivations of Penicillium chrysogenum Lead to Rapid Metabolite, Flux and Productivity Responses

Metabolites ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 45
Author(s):  
Qi Yang ◽  
Wenli Lin ◽  
Jiawei Xu ◽  
Nan Guo ◽  
Jiachen Zhao ◽  
...  
Keyword(s):  
Steady State ◽  
Dissolved Oxygen ◽  
Penicillium Chrysogenum ◽  
Large Scale ◽  
Scale Up ◽  
Redox Status ◽  
Oxygen Availability ◽  
Industrial Scale ◽  
Cell Factory ◽  
Microbial Cell Factory

Bioreactor scale-up from the laboratory scale to the industrial scale has always been a pivotal step in bioprocess development. However, the transition of a bioeconomy from innovation to commercialization is often hampered by performance loss in titer, rate and yield. These are often ascribed to temporal variations of substrate and dissolved oxygen (for instance) in the environment, experienced by microorganisms at the industrial scale. Oscillations in dissolved oxygen (DO) concentration are not uncommon. Furthermore, these fluctuations can be exacerbated with poor mixing and mass transfer limitations, especially in fermentations with filamentous fungus as the microbial cell factory. In this work, the response of glucose-limited chemostat cultures of an industrial Penicillium chrysogenum strain to different dissolved oxygen levels was assessed under both DO shift-down (60% → 20%, 10% and 5%) and DO ramp-down (60% → 0% in 24 h) conditions. Collectively, the results revealed that the penicillin productivity decreased as the DO level dropped down below 20%, while the byproducts, e.g., 6-oxopiperidine-2-carboxylic acid (OPC) and 6-aminopenicillanic acid (6APA), accumulated. Following DO ramp-down, penicillin productivity under DO shift-up experiments returned to its maximum value in 60 h when the DO was reset to 60%. The result showed that a higher cytosolic redox status, indicated by NADH/NAD+, was observed in the presence of insufficient oxygen supply. Consistent with this, flux balance analysis indicated that the flux through the glyoxylate shunt was increased by a factor of 50 at a DO value of 5% compared to the reference control, favoring the maintenance of redox status. Interestingly, it was observed that, in comparison with the reference control, the penicillin productivity was reduced by 25% at a DO value of 5% under steady state conditions. Only a 14% reduction in penicillin productivity was observed as the DO level was ramped down to 0. Furthermore, intracellular levels of amino acids were less sensitive to DO levels at DO shift-down relative to DO ramp-down conditions; this difference could be caused by different timescales between turnover rates of amino acid pools (tens of seconds to minutes) and DO switches (hours to days at steady state and minutes to hours at ramp-down). In summary, this study showed that changes in oxygen availability can lead to rapid metabolite, flux and productivity responses, and dynamic DO perturbations could provide insight into understanding of metabolic responses in large-scale bioreactors.

scholarly journals Modular and Integrative Vectors for Synthetic Biology Applications in Streptomyces spp.

2019 ◽  
Vol 85 (16) ◽  
Author(s):  
Céline Aubry ◽  
Jean-Luc Pernodet ◽  
Sylvie Lautru
Keyword(s):  
Synthetic Biology ◽  
Anticancer Agents ◽  
Gene Clusters ◽  
Bioactive Molecules ◽  
Dna Assembly ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Dna Cloning ◽  
Specialized Metabolism ◽  
Assembly Method

ABSTRACT With the development of synthetic biology in the field of (actinobacterial) specialized metabolism, new tools are needed for the design or refactoring of biosynthetic gene clusters. If libraries of synthetic parts (such as promoters or ribosome binding sites) and DNA cloning methods have been developed, to our knowledge, not many vectors designed for the flexible cloning of biosynthetic gene clusters have been constructed. We report here the construction of a set of 12 standardized and modular vectors designed to afford the construction or the refactoring of biosynthetic gene clusters in Streptomyces species, using a large panel of cloning methods. Three different resistance cassettes and four orthogonal integration systems are proposed. In addition, FLP recombination target sites were incorporated to allow the recycling of antibiotic markers and to limit the risks of unwanted homologous recombination in Streptomyces strains when several vectors are used. The functionality and proper integration of the vectors in three commonly used Streptomyces strains, as well as the functionality of the Flp-catalyzed excision, were all confirmed. To illustrate some possible uses of our vectors, we refactored the albonoursin gene cluster from Streptomyces noursei using the BioBrick assembly method. We also used the seamless ligase chain reaction cloning method to assemble a transcription unit in one of the vectors and genetically complement a mutant strain. IMPORTANCE One of the strategies employed today to obtain new bioactive molecules with potential applications for human health (for example, antimicrobial or anticancer agents) is synthetic biology. Synthetic biology is used to biosynthesize new unnatural specialized metabolites or to force the expression of otherwise silent natural biosynthetic gene clusters. To assist the development of synthetic biology in the field of specialized metabolism, we constructed and are offering to the community a set of vectors that were intended to facilitate DNA assembly and integration in actinobacterial chromosomes. These vectors are compatible with various DNA cloning and assembling methods. They are standardized and modular, allowing the easy exchange of a module by another one of the same nature. Although designed for the assembly or the refactoring of specialized metabolite gene clusters, they have a broader potential utility, for example, for protein production or genetic complementation.

scholarly journals Modular, synthetic chromosomes as new tools for large scale engineering of metabolism

2021 ◽  
Author(s):  
Eline Postma ◽  
Else-Jasmijn Hassing ◽  
Venda Mangkusaputra ◽  
Jordi Geelhoed ◽  
Pilar de la Torre ◽  
...  
Keyword(s):  
Copy Number ◽  
Large Scale ◽  
Metabolic Networks ◽  
De Novo ◽  
Microbial Cell ◽  
Cell Factory ◽  
Microbial Cell Factory ◽  
Microbial Cell Factories ◽  
Cell Factories

The construction of powerful cell factories requires intensive genetic engineering for the addition of new functionalities and the remodeling of native pathways and processes. The present study demonstrates the feasibility of extensive genome reprogramming using modular, specialized de novo-assembled neochromosomes in yeast. The in vivo assembly of linear and circular neochromosomes, carrying 20 native and 21 heterologous genes, enabled the first de novo production in a microbial cell factory of anthocyanins, plant compounds with a broad range pharmacological properties. Turned into exclusive expression platforms for heterologous and essential metabolic routes, the neochromosomes mimic native chromosomes regarding mitotic and genetic stability, copy number, harmlessness for the host and editability by CRISPR/Cas9. This study paves the way for future microbial cell factories with modular genomes in which core metabolic networks, localized on satellite, specialized neochromosomes can be swapped for alternative configurations and serve as landing pads for the addition of functionalities.

scholarly journals A Streptomyces venezuelae Cell-Free Toolkit for Synthetic Biology

2020 ◽  
Author(s):  
Simon J Moore ◽  
Hung-En Lai ◽  
Soo-Mei Chee ◽  
Ming Toh ◽  
Seth Coode ◽  
...  
Keyword(s):  
Synthetic Biology ◽  
Gene Clusters ◽  
Test Tube ◽  
High Yield ◽  
Proof Of Concept ◽  
Biosynthetic Gene Clusters ◽  
Reaction Conditions ◽  
One Pot ◽  
Free System ◽  
High Level

AbstractProkaryotic cell-free coupled transcription-translation (TX-TL) systems are emerging as a powerful tool to examine natural product biosynthetic pathways in a test-tube. The key advantages of this approach are the reduced experimental timescales and controlled reaction conditions. In order to realise this potential, specialised cell-free systems in organisms enriched for biosynthetic gene clusters, with strong protein production and well-characterised synthetic biology tools, is essential. The Streptomyces genus is a major source of natural products. To study enzymes and pathways from Streptomyces, we originally developed a homologous Streptomyces cell-free system to provide a native protein folding environment, a high G+C (%) tRNA pool and an active background metabolism. However, our initial yields were low (36 μg/mL) and showed a high level of batch-to-batch variation. Here, we present an updated high-yield and robust Streptomyces TX-TL protocol, reaching up to yields of 266 μg/mL of expressed recombinant protein. To complement this, we rapidly characterise a range of DNA parts with different reporters, express high G+C (%) biosynthetic genes and demonstrate an initial proof of concept for combined transcription, translation and biosynthesis of Streptomyces metabolic pathways in a single ‘one-pot’ reaction.

Acinetobacter baylyi ADP1—naturally competent for synthetic biology

2021 ◽  
Author(s):  
Suvi Santala ◽  
Ville Santala
Keyword(s):  
Synthetic Biology ◽  
Cell Factory ◽  
Bacterial Genetics ◽  
Metabolic Diversity ◽  
Acinetobacter Baylyi ◽  
Microbial Cell Factory ◽  
Strong Base ◽  
Rational Engineering ◽  
Recombination Efficiency ◽  
Acinetobacter Baylyi Adp1

Abstract Acinetobacter baylyi ADP1 is a non-pathogenic soil bacterium known for its metabolic diversity and high natural transformation and recombination efficiency. For these features, A. baylyi ADP1 has been long exploited in studying bacterial genetics and metabolism. The large pool of information generated in the fundamental studies has facilitated the development of a broad range of sophisticated and robust tools for the genome and metabolic engineering of ADP1. This mini-review outlines and describes the recent advances in ADP1 engineering and tool development, exploited in, for example, pathway and enzyme evolution, genome reduction and stabilization, and for the production of native and non-native products in both pure and rationally designed multispecies cultures. The rapidly expanding toolbox together with the unique features of A. baylyi ADP1 provide a strong base for a microbial cell factory excelling in synthetic biology applications where evolution meets rational engineering.

scholarly journals Microbial response to acid stress: mechanisms and applications

2019 ◽  
Vol 104 (1) ◽  
pp. 51-65 ◽  
Author(s):  
Ningzi Guan ◽  
Long Liu
Keyword(s):  
Synthetic Biology ◽  
Metabolic Regulation ◽  
Membrane Integrity ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Industrial Applications ◽  
Cell Factory ◽  
Ph Homeostasis ◽  
Tolerance Mechanisms ◽  
Microbial Cell Factory

AbstractMicroorganisms encounter acid stress during multiple bioprocesses. Microbial species have therefore developed a variety of resistance mechanisms. The damage caused by acidic environments is mitigated through the maintenance of pH homeostasis, cell membrane integrity and fluidity, metabolic regulation, and macromolecule repair. The acid tolerance mechanisms can be used to protect probiotics against gastric acids during the process of food intake, and can enhance the biosynthesis of organic acids. The combination of systems and synthetic biology technologies offers new and wide prospects for the industrial applications of microbial acid tolerance mechanisms. In this review, we summarize acid stress response mechanisms of microbial cells, illustrate the application of microbial acid tolerance in industry, and prospect the introduction of systems and synthetic biology to further explore the acid tolerance mechanisms and construct a microbial cell factory for valuable chemicals.

scholarly journals Large-Scale Metagenome Assembly Reveals Novel Animal-Associated Microbial Genomes, Biosynthetic Gene Clusters, and Other Genetic Diversity

mSystems ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Nicholas D. Youngblut ◽  
Jacobo de la Cuesta-Zuluaga ◽  
Georg H. Reischer ◽  
Silke Dauser ◽  
Nathalie Schuster ◽  
...  
Keyword(s):  
Large Scale ◽  
Animal Species ◽  
Gene Clusters ◽  
Genomic Diversity ◽  
Data Sets ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Microbial Genomes ◽  
Metagenome Assembly ◽  
Gut Metagenome

ABSTRACT Large-scale metagenome assemblies of human microbiomes have produced a vast catalogue of previously unseen microbial genomes; however, comparatively few microbial genomes derive from other vertebrates. Here, we generated 5,596 metagenome-assembled genomes (MAGs) from the gut metagenomes of 180 predominantly wild animal species representing 5 classes, in addition to 14 existing animal gut metagenome data sets. The MAGs comprised 1,522 species-level genome bins (SGBs), most of which were novel at the species, genus, or family level, and the majority were enriched in host versus environment metagenomes. Many traits distinguished SGBs enriched in host or environmental biomes, including the number of antimicrobial resistance genes. We identified 1,986 diverse biosynthetic gene clusters; only 23 clustered with any MIBiG database references. Gene-based assembly revealed tremendous gene diversity, much of it host or environment specific. Our MAG and gene data sets greatly expand the microbial genome repertoire and provide a broad view of microbial adaptations to the vertebrate gut. IMPORTANCE Microbiome studies on a select few mammalian species (e.g., humans, mice, and cattle) have revealed a great deal of novel genomic diversity in the gut microbiome. However, little is known of the microbial diversity in the gut of other vertebrates. We studied the gut microbiomes of a large set of mostly wild animal species consisting of mammals, birds, reptiles, amphibians, and fish. Unfortunately, we found that existing reference databases commonly used for metagenomic analyses failed to capture the microbiome diversity among vertebrates. To increase database representation, we applied advanced metagenome assembly methods to our animal gut data and to many public gut metagenome data sets that had not been used to obtain microbial genomes. Our resulting genome and gene cluster collections comprised a great deal of novel taxonomic and genomic diversity, which we extensively characterized. Our findings substantially expand what is known of microbial genomic diversity in the vertebrate gut.

scholarly journals Comparative genomics uncovers genetic diversity and synthetic biology of secondary metabolite production of the genus Trametes

2019 ◽  
Author(s):  
Yan Zhang ◽  
Jie Cao ◽  
Jingjing Wang ◽  
Yajun Cheng ◽  
Minghui Zhou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Synthetic Biology ◽  
Secondary Metabolite ◽  
Gene Clusters ◽  
Glycoside Hydrolases ◽  
Secondary Metabolite Production ◽  
Crystalline Cellulose ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Metabolite Production

Abstract It’s well-established that the CAZyme genes of genus Trametes contributed to the degradation processes of polysaccharides, including lignin or crystalline cellulose. However, the comprehensive analysis of the composition of CAZymes and the biosynthetic gene clusters of Trametes genus remain unclear. We conducted comparative analysis, detected the CAZyme genes, and predicted the biosynthetic gene clusters for 9 Trametes strains. Among 82,053 homologous clusters we obtained for genus Trametes, we identified 8,518 core genes, 60,441 accessory genes and 13,094 specific genes. Our results showed that a large proportion of CAZyme genes were catalogued into glycoside hydrolases, glycosyltransferases, and carbohydrate esterases. The predicted BGCs of Trametes genus were divided into 6 strategies and the 9 Trametes strains harbored 47.78 BGCs on average. Our study uncovers the genus Trametes exhibited an open pan-genome structure, provides insights into the genetic diversity and explores the synthetic biology of secondary metabolite production for Trametes genus.

scholarly journals TaxiBGC: a Taxonomy-guided Approach for the Identification of Experimentally Verified Microbial Biosynthetic Gene Clusters in Shotgun Metagenomic Data

2021 ◽  
Author(s):  
Utpal Bakshi ◽  
Vinod K Gupta ◽  
Aileen R Lee ◽  
John M Davis ◽  
Sriram Chandrasekaran ◽  
...  
Keyword(s):  
Large Scale ◽  
Human Microbiome ◽  
Gene Clusters ◽  
Human Microbiome Project ◽  
Metagenomic Data ◽  
Biosynthetic Gene ◽  
Case Control Studies ◽  
Biosynthetic Gene Clusters ◽  
Host Interactions ◽  
Microbiome Data

Biosynthetic gene clusters (BGCs) in microbial genomes encode for the production of bioactive secondary metabolites (SMs). Given the well-recognized importance of SMs in microbe-microbe and microbe-host interactions, the large-scale identification of BGCs from microbial metagenomes could offer novel functional insights into complex chemical ecology. Despite recent progress, currently available tools for predicting BGCs from shotgun metagenomes have several limitations, including the need for computationally demanding read-assembly and prediction of a narrow breadth of BGC classes. To overcome these limitations, we developed TaxiBGC (Taxonomy-guided Identification of Biosynthetic Gene Clusters), a computational pipeline for identifying experimentally verified BGCs in shotgun metagenomes by first pinpointing the microbial species likely to produce them. We show that our species-centric approach was able to identify BGCs in simulated metagenomes more accurately than by solely detecting BGC genes. By applying TaxiBGC on 5,423 metagenomes from the Human Microbiome Project and various case-control studies, we identified distinct BGC signatures of major human body sites and candidate stool-borne biomarkers for multiple diseases, including inflammatory bowel disease, colorectal cancer, and psychiatric disorders. In all, TaxiBGC demonstrates a significant advantage over existing techniques for systematically characterizing BGCs and inferring their SMs from microbiome data.

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