Manipulating Bacterial Biofilms Using Materiobiology and Synthetic Biology Approaches

Cyanobacteria fouling in photobioreactors: current status and future perspectives for prevention

Cyanobacteria biomass sources have the potential to contribute to the replacement of fossil fuels and to the reduction in global warming by sustainable conversion of atmospheric CO2 into biofuels and high-value chemicals. Cyanobacteria cultivation in photobioreactors (PBRs) results in biofouling on their transparent inner walls, which reduces photosynthetic efficiency and productivity. While cyanobacteria biofouling in PBRs is recognized as a significant operating challenge, this review draws attention to the lack of studies on antifouling strategies for PBRs involving cyanobacteria and discusses several areas related to cyanobacteria fouling mechanisms on PBR materials, which require further investigation. These include an in-depth analysis of conditioning films, the role of pili and EPS in gliding and adhesion, potential revisions to existing theoretical models for predicting adhesion, and material properties that affect cyanobacteria adhesion. We use knowledge from marine, medical, and industrial biofouling management to help identify strategies to combat cyanobacteria fouling in PBRs, and we review the applicability of various bioinspired physical and chemical strategies, as well as genetic engineering approaches to prevent cyanobacteria biofilm formation in PBRs.

Biofilm-mediated bioremediation of xenobiotics and heavy metals: a comprehensive review of microbial ecology, molecular mechanisms, and emerging biotechnological applications

Environmental pollution, driven by rapid industrialization and urbanization, has emerged as a critical global challenge in the twenty-first century. This comprehensive review explores the potential of bacterial biofilms in bioremediation, focusing on their ability to degrade and transform a wide array of pollutants, including heavy metals, persistent organic pollutants (POPs), oil spills, pesticides, and emerging contaminants, such as pharmaceuticals and microplastics. The unique structural and functional characteristics of biofilms, including their extracellular polymeric substance (EPS) matrix, enhanced genetic exchange, and metabolic cooperation, contribute to their superior pollutant degradation capabilities compared to planktonic bacteria. Recent advancements in biofilm-mediated bioremediation include the application of genetically engineered microorganisms, nanoparticle-biofilm interactions, and innovative biofilm reactor designs. The CRISPR-Cas9 system has shown promise in enhancing the degradative capabilities of biofilm-forming bacteria while integrating nanoparticles with bacterial biofilms demonstrates significant improvements in pollutant degradation efficiency. As global pollution rises, biofilm-based bioremediation emerges as a cost-effective and environmentally friendly approach to address diverse contaminants. This review signifies the need for further research to optimize these techniques and harness their full potential in addressing pressing environmental challenges.

Electrogenic Staphylococcus epidermidis Diminishes the Ultraviolet B-Induced Labile Irons in Mouse Skin

The tremendous abundance of Staphylococcus epidermidis (S. epidermidis) on the skin surface have been found electrogenic. However, the role of electrogenic S. epidermidis in biological activities remains elusive. Addition of S. epidermidis plus glycerol reinstated the reduction of electric currents of vancomycin-treated human skin bacteria collected by skin swabs. In the presence of glycerol, an endogenous molecule in human skin, S. epidermidis exerted the electrogenicity measured by the changes in voltages and currents as well as ferrozine assays. A substantial increase in iron contents in skin was detected when mouse skin was exposed to ultraviolet B (UV-B). Topical application of S. epidermidis plus glycerol onto mouse skin mitigated the UV-B-induced production of labile ferrous iron, demonstrating that S. epidermidis electricity acted as a regulator of the redox cycling of irons in skin. Low expression of cyclophilin A, an electron mediator, in S. epidermidis caused the loss of bacterial activities to reduce the UV-B-induced labile ferrous iron. Cumulatively, skin electrogenic S. epidermidis may mediate cyclophilin A to combat the UV-B-induced iron imbalance in skin.

Bacterial Communities and Their Role in Bacterial Infections

Since infections associated with microbial communities threaten human health, research is increasingly focusing on the development of biofilms and strategies to combat them. Bacterial communities may include bacteria of one or several species. Therefore, examining all the microbes and identifying individual community bacteria responsible for the infectious process is important. Rapid and accurate detection of bacterial pathogens is paramount in healthcare, food safety, and environmental monitoring. Here, we analyze biofilm composition and describe the main groups of pathogens whose presence in a microbial community leads to infection (Staphylococcus aureus, Enterococcus spp., Cutibacterium spp., bacteria of the HACEK, etc.). Particular attention is paid to bacterial communities that can lead to the development of device-associated infections, damage, and disruption of the normal functioning of medical devices, such as cardiovascular implants, biliary stents, neurological, orthopedic, urological and penile implants, etc. Special consideration is given to tissue-located bacterial biofilms in the oral cavity, lungs and lower respiratory tract, upper respiratory tract, middle ear, cardiovascular system, skeletal system, wound surface, and urogenital system. We also describe methods used to analyze the bacterial composition in biofilms, such as microbiologically testing, staining, microcolony formation, cellular and extracellular biofilm components, and other methods. Finally, we present ways to reduce the incidence of biofilm-caused infections.

Functionalization of Alginate Hydrogels with a Multifunctional Peptide Supports Mesenchymal Stem Cell Adhesion and Reduces Bacterial Colonization

Hydrogels with cell adhesive moieties stand out as promising materials to enhance tissue healing and regeneration. Nonetheless, bacterial infections of the implants represent an unmet major concern. In the present work, we developed an alginate hydrogel modified with a multifunctional peptide containing the RGD cell adhesive motif in combination with an antibacterial peptide derived from the 1-11 region of lactoferrin (LF). The RGD-LF branched peptide was successfully anchored to the alginate backbone by carbodiimide chemistry, as demonstrated by 1H NMR and fluorescence measurements. The functionalized hydrogel presented desirable physicochemical properties (porosity, swelling and rheological behavior) to develop biomaterials for tissue engineering. The viability of mesenchymal stem cells (MSCs) on the peptide-functionalized hydrogels was excellent, with values higher than 85 % at day 1, and higher than 95 % after 14 days in culture. Moreover, the biological characterization demonstrated the ability of the hydrogels to significantly enhance ALP activity of MSCs as well as to decrease bacterial colonization of both Gram-positive and Gram-negative models. Such results prove the potential of the functionalized hydrogels as novel biomaterials for tissue engineering, simultaneously displaying cell adhesive activity and the capacity to prevent bacterial contamination, a dual bioactivity commonly not found for these types of hydrogels.

Engineered plastic-associated bacteria for biodegradation and bioremediation

The global plastic waste crisis has triggered the development of novel methods for removal of recalcitrant polymers from the environment. Biotechnological approaches have received particular attention due to their potential for enabling sustainable, low-intensity bioprocesses which could also be interfaced with microbial upcycling pathways to support the emerging circular bioeconomy. However, low biodegradation efficiency of solid plastic materials remains a bottleneck, especially at mesophilic conditions required for one-pot degradation and upcycling. A promising strategy used in nature to address this is localisation of plastic-degrading microbes to the plastic surface via biofilm-mediated surface association. This review highlights progress and opportunities in leveraging these naturally occurring mechanisms of biofilm formation and other cell-surface adhesion biotechnologies to co-localise engineered cells to plastic surfaces. We further discuss examples of combining these approaches with extracellular expression of plastic-degrading enzymes to accelerate plastic degradation. Additionally, we review this topic in the context of nano- and microplastics bioremediation and their removal from wastewater and finally propose future research directions for this nascent field.

Coupling of gene regulation and carrier modification manipulates bacterial biofilms as robust living catalysts

The biofilm of an engineered strain is limited by slow growth and low yield, resulting in an unsatisfactory ability to resist external stress and promote catalytic efficiency. Here, biofilms used as robust living catalysts were manipulated through dual functionalized gene regulation and carrier modification strategies. The results showed that gene overexpression regulates the autoinducer-2 activity, extracellular polymeric substance content and colony behavior of Escherichia coli, and the biofilm yield of csgD overexpressed strains increased by 79.35 % compared to that of the wild type strains (p < 0.05). In addition, the hydrophilicity of polyurethane fibres modified with potassium dichromate increased significantly, and biofilm adhesion increased by 105.80 %. Finally, the isoquercitrin yield in the catalytic reaction of the biofilm reinforced by the csgD overexpression strain and the modified carrier was 247.85 % higher than that of the untreated group. Overall, this study has developed engineered strains biofilm with special functions, providing possibilities for catalytic applications.

AIEgen orthopalladated hybrid polymers for efficient inactivation of the total coliforms in urban wastewater

Monitorable AIE polymers with a bioactive pattern are employed in advanced biomedical applications such as functional coatings, theranostic probes, and implants. After the global COVID-19 pandemic, interest in developing surfaces with superior antimicrobial, antiproliferative, and antiviral activities dramatically increased. Many formulations for biocide surfaces are based on hybrid organic/inorganic materials. Palladium (II) complexes display relevant activity against common bacteria, even higher when compared to their uncoordinated ligands. This article reports the design and synthesis of two series of orthopalladated polymers obtained by grafting a cyclopalladated fragment on two different O, N chelating Schiff base polymers. Different grafting percentages were examined and compared for each organic polymer. The fluorescence emission in the solid state was explored on organic matrixes and grafted polymers. DFT analysis provided a rationale for the role of the coordination core. The antibacterial response of the two series of hybrid polymers was tested against the total coliform group of untreated urban wastewater, revealing excellent inactivation ability.

Green biomanufacturing in recombinant collagen biosynthesis: trends and selection in various expression systems

Collagen, classically derived from animal tissue, is an all-important protein material widely used in biomedical materials, cosmetics, fodder, food, etc. The production of recombinant collagen through different biological expression systems using bioengineering techniques has attracted significant interest in consideration of increasing market demand and the process complexity of extraction. Green biomanufacturing of recombinant collagen has become one of the focus topics. While the bioproduction of recombinant collagens (type I, II, III, etc.) has been commercialized in recent years, the biosynthesis of recombinant collagen is extremely challenging due to protein immunogenicity, yield, degradation, and other issues. The rapid development of synthetic biology allows us to perform a heterologous expression of proteins in diverse expression systems, thus optimizing the production and bioactivities of recombinant collagen. This review describes the research progress in the bioproduction of recombinant collagen over the past two decades, focusing on different expression systems (prokaryotic organisms, yeasts, plants, insects, mammalian and human cells, etc.). We also discuss the challenges and future trends in developing market-competitive recombinant collagens.