Antibiotics-Free Steady Bioproduction of Valuable Chemicals from Organic Wastes by Engineered through Targeted Gene Integration.

Bioproduction of chemicals by using engineered bacteria is promising for a circular economy but challenged the instability of the introduced plasmid by conventional methods. Here, we developed a two-plasmid INTEGRET system to reliably integrate the targeted gene into the genome, making it a powerful strain for efficient and steady bioproduction without requiring antibiotic addition. The INTEGRET system allows for gene insertion at over 75% inserting efficiency and flexibly controllable gene dosages.

Modularized Engineering of Shewanella oneidensis MR-1 for Efficient and Directional Synthesis of 5-Aminolevulinic Acid.

Shewanella oneidensis MR-1 has found widespread applications in pollutant transformation and bioenergy production, closely tied to its outstanding heme synthesis capabilities. However, this significant biosynthetic potential is still unexploited so far. Here, we turned this bacterium into a highly-efficient bio-factory for green synthesis of 5-Aminolevulinic Acid (5-ALA), an important chemical for broad applications in agriculture, medicine, and the food industries.

Phthalates Boost Natural Transformation of Extracellular Antibiotic Resistance Genes through Enhancing Bacterial Motility and DNA Environmental Persistence.

The environmental dissemination of extracellular antibiotic resistance genes (eARGs) in wastewater and natural water bodies has aroused growing ecological concerns. The coexisting chemical pollutants in water are known to markedly affect the eARGs transfer behaviors of the environmental microbial community, but the detailed interactions and specific impacts remain elusive so far. Here, we revealed a concentration-dependent impact of dimethyl phthalate (DMP) and several other types of phthalate esters (common water pollutants released from plastics) on the natural transformation of eARGs.

Nonsterilized Fermentation of Crude Glycerol for Polyhydroxybutyrate Production by Metabolically Engineered .

Polyhydroxybutyrate (PHB) is an attractive biodegradable polymer that can be produced through the microbial fermentation of organic wastes or wastewater. However, its mass production has been restricted by the poor utilization of organic wastes due to the presence of inhibitory substances, slow microbial growth, and high energy input required for feedstock sterilization. Here, , a fast-growing bacterium with a broad substrate spectrum and high tolerance to salt and toxic substances, was genetically engineered to enable efficient PHB production from nonsterilized fermentation of organic wastes.

Efficient and precise control of gene expression in Geobacter sulfurreducens through new genetic elements and tools for pollutant conversion.

Geobacter species, exhibiting exceptional extracellular electron transfer aptitude, hold great potential for applications in pollution remediation, bioenergy production, and natural elemental cycles. Nonetheless, a scarcity of well-characterized genetic elements and gene expression tools constrains the effective and precise fine-tuning of gene expression in Geobacter species, thereby limiting their applications. Here, we examined a suite of genetic elements and developed a new genetic editing tool in Geobacter sulfurreducens to enhance their pollutant conversion capacity.

Phthalates Promote Dissemination of Antibiotic Resistance Genes: An Overlooked Environmental Risk.

Plastics-microorganism interactions have aroused growing environmental and ecological concerns. However, previous studies concentrated mainly on the direct interactions and paid little attention to the ecotoxicology effects of phthalates (PAEs), a common plastic additive that is continuously released and accumulates in the environment. Here, we provide insights into the impacts of PAEs on the dissemination of antibiotic resistance genes (ARGs) among environmental microorganisms.

Biomolecular Insights into Extracellular Pollutant Reduction Pathways of Using a Base Editor System.

species are critically involved in elemental biogeochemical cycling and environmental bioremediation processes via extracellular electron transfer (EET), but the underlying biomolecular mechanisms remain elusive due to lack of effective analytical tools to explore into complicated EET networks. Here, a simple and highly efficient cytosine base editor was developed for engineering of the slow-growing (a doubling time of 5 h with acetate as the electron donor and fumarate as the electron acceptor). A single-plasmid cytosine base editor (pYYDT-BE) was constructed in by fusing cytosine deaminase, Cas9 nickase, and a uracil glycosylase inhibitor.

Anaerobic self-assembly of a regenerable bacteria-quantum dot hybrid for solar hydrogen production.

Inorganic-biological hybrid systems (bio-hybrids), comprising fermentative bacteria and inorganic semiconductor photosensitizers for synergistic utilization of solar energy and organic wastes, offer opportunities for sustainable fuel biosynthesis, but the low quantum efficiency, photosensitizer biotoxicity and inability for self-regeneration are remaining hurdles to practical application. Here, we unveil a previously neglected role of oxygen in suppressing the biosynthesis of cadmium selenide quantum dots (CdSe QDs) and the metabolic activities of , and accordingly propose a simple oxygen-regulation strategy to enable the self-assembly of bacterial-QD hybrids for efficient solar hydrogen production. Shifting from aerobic to anaerobic biosynthesis significantly lowered the intracellular reactive oxygen species level and increased NADPH and thiol-protein production, enabling a two-order-of-magnitude higher bio-QD synthesis rate and resulting in CdSe-rich products.

Self-regenerable bio-hybrid with biogenic ferrous sulfide nanoparticles for treating high-concentration chromium-containing wastewater.

Biogenic ferrous sulfide nanoparticles (bio-FeS) as low-cost and green-synthesized nanomaterial are promising for heavy metals removal, but the need for complicated extraction, storage processes and the production of iron sludge still restrict their practical application. Here, a self-regenerable bio-hybrid consisting of bacterial cells and self-assembled bio-FeS was developed to efficiently remove chromium (Cr(VI)). A dense layer of bio-FeS was distributed on the cell surface and in the periplasmic space of Shewanella oneidensis MR-1, endowing the bacterium with good Cr(VI) tolerance and unusual activity for bio-FeS-mediated Cr(VI) reduction.

Developing a base-editing system to expand the carbon source utilization spectra of Shewanella oneidensis MR-1 for enhanced pollutant degradation.

Shewanella oneidensis MR-1, a model strain of exoelectrogenic bacteria (EEB), plays a key role in environmental bioremediation and bioelectrochemical systems because of its unique respiration capacity. However, only a narrow range of substrates can be utilized by S. oneidensis MR-1 as carbon sources, resulting in its limited applications.

CRISPRi System as an Efficient, Simple Platform for Rapid Identification of Genes Involved in Pollutant Transformation by .

species are indigenous in diverse aquatic environments and play important roles in environmental remediation. However, the pollutant transformation mechanisms of these bacteria remain elusive, and their potential in pollution control is largely unexploited so far. In this work, we report an efficient and simple genome regulation tool to edit and identify its biomolecular pathways for pollutant transformation.