Electrospun Microbial-Encapsulated Composite-Based Plasticized Seed Coat for Rhizosphere Stabilization and Sustainable Production of Canola ( Brassica napus L.)

E-seed skin: a carbohydrate-protein hybrid nanostructure for delayed germination and accelerated growth

The main purpose of the seed industry is to cater seeds with desired strength and viability, for which seed coating is a basic requirement. Herein, a hybrid coating of an electrosprayed protein (collagen) on electrospun nanofibers having a multidentate zinc-reinforced carbohydrate (pectin)/PVA composite (PVA/Pec/Zn/Col-NF) was developed. The zinc ensured covalent binding with the -OH in pectin/PVA in addition to the native galvanic binding between the polymers. Along with this, hydrogen bonding interactions between the -NH2 groups of electrosprayed collagen and the -OH groups in PVA/pectin further enabled the formation of a highly stable nanostructure. Controlled electrodeposition of collagen nanoparticles on the PVA/Pec/Zn-NF led to a decreased surface roughness scale with enhanced moisture resistance. The humidity resistance of the coating and the participation of zinc as a nutrient delayed the germination by 8 days and accelerated the tomato seedling's growth by approximately two times, respectively. The presence of zinc in the coating formulation enabled oxidative stress protection by boosting the superoxide dismutase activity. Moreover, the fungal resistance of the coating enabled the seeds to germinate even in the presence of phytopathogens. Thus, the approach of using the developed PVA/Pec/Zn/Col-NF coating material to construct a tight packing without affecting viability of the seed demonstrates a pioneering seed coating technique for increasing global food security amidst climate change and global warming.

Electric Field Polarity Controls Distribution of Viral Bioreceptors within Near-Field Electrospun Biohybrid Microfiber Optical Biosensors

Microorganisms (e.g., bacteria, fungi, and viruses) add indispensable functionality to a range of electrospun polymer materials and devices. The optimal distribution of bioactive agents on either the interior or exterior of the fiber is application-specific. Current microbe surface immobilization strategies and core-confinement techniques continue to pose a number of challenges. Here, we explore a simple strategy, utilizing electrostatic forces, to control the migration and surface concentration of the M13 bacteriophage within near-field electrospun poly(vinyl alcohol) (PVA) microfibers. Both the surface charge of the electrospun virus and the applied electric field polarity altered microbe placement. When doped with Rhodamine 6G (R6G), the circular microfiber cross sections formed active whispering gallery mode (WGM) resonators. These relatively high-quality (Q) optical cavities enabled us to sensitively probe the virus content of their outer layer, while functioning as label-free optical biosensors with phage-based streptavidin biorecognition elements. Coulomb forces displayed significant control over M13 surface coverage during near-field electrospinning, increasing biosensor response by nearly a factor of 4 to 1310 nM streptavidin. These findings are an important demonstration of electrostatic forces as a simple, yet adaptable method to enhance biohybrid fiber functionality and performance by tailoring microbe distribution.

Can polymeric nanofibers effectively preserve and deliver live therapeutic bacteria?

Probiotics and live therapeutic bacteria (LTB), their strictly regulated therapeutic counterpart, are increasingly important in treating and preventing biofilm-related diseases. This necessitates new approaches to (i) preserve bacterial viability during manufacturing and storage and (ii) incorporate LTB into delivery systems for enhanced therapeutic efficacy. This review explores advances in probiotic and LTB product development, focusing on preservation, protection, and improved delivery. Preservation of bacteria can be achieved by drying methods that decelerate metabolism. These methods introduce stresses affecting viability which can be mitigated with suitable excipients like polymeric or low molecular weight stabilizers. The review emphasizes the incorporation of LTB into polymer-based nanofibers via electrospinning, enabling simultaneous drying, encapsulation, and delivery system production. Optimization of bacterial survival during electrospinning and storage is discussed, as well as controlled LTB release achievable through formulation design using gel-forming, gastroprotective, mucoadhesive, and pH-responsive polymers. Evaluation of the presence of the actual therapeutic strains, bacterial viability and activity by CFU enumeration or alternative analytical techniques is presented as a key aspect of developing effective and safe formulations with LTB. This review offers insights into designing delivery systems, especially polymeric nanofibers, for preservation and delivery of LTB, guiding readers in developing innovative biotherapeutic delivery systems.

Nano-biofertilizers: utilizing nanopolymers as coating matrix-a comprehensive review

In modern agriculture, nanotechnology was recognized as a potentially transformative innovation. Nanopolymers as coating matrix in nano-biofertilizer has a massive impact on agricultural productivity. The integration of nanotechnology with biofertilizers has led to the creation of nano-biofertilizer formulations that enhance nutrient delivery, improve plant growth, and increase resistance to environmental stress. Nanopolymers, both synthetic and biogenic, including chitosan, cellulose, gelatin, sodium alginate, starch, and polyvinyl alcohol, are utilized as encapsulating materials. They are effective in ensuring controlled nutrient release and shielding beneficial microorganisms from external environmental conditions. Studies indicate that nano-biofertilizers improve soil quality, raise crop yields, and reduce the usage of chemical fertilizers to enhance sustainable agricultural practices. The review also addresses the microbial encapsulation methodology, release kinetics, phytotoxicity, challenges and future prospects of nano-biofertilizer technology, including nanoparticle-bacteria interaction, scalability, and regulatory considerations. This paper elaborates the potential and limitations of nano-biofertilizers, providing insights for future advancements in the agriculture field.

Identification of non-canonical antagonistic bacteria via interspecies contact-dependent killing

BACKGROUND

Canonical biocontrol bacteria were considered to inhibit pathogenic bacteria mainly by secreting antibiotic metabolites or enzymes. Recent studies revealed that some biocontrol bacteria can inhibit pathogenic bacteria through contact-dependent killing (CDK) mediated by contact-dependent secretion systems. The CDK was independent of antibiotic metabolites and often ignored in normal biocontrol activity assay.

RESULTS

In this study, we aimed to use a pathogen enrichment strategy to isolate non-canonical bacteria with CDK ability. Rhizosphere soil samples from Chinese cabbage showing soft rot symptom were collected and Pectobacterium carotovorum subsp. carotovorum (Pcc), the pathogen of cabbage soft rot, were added into these samples to enrich bacteria which attached on Pcc cells. By co-culture with Pcc, four bacteria strains (named as PcE1, PcE8, PcE12 and PcE13) showing antibacterial activity were isolated from Chinese cabbage rhizosphere. These four bacteria strains showed CDK abilities to different pathogenic bacteria of horticultural plants. Among them, PcE1 was identified as Chryseobacterium cucumeris. Genome sequencing showed that PcE1 genome encoded a type VI secretion system (T6SS) gene cluster. By heterologous expression, four predicted T6SS effectors of PcE1 showed antibacterial activity to Escherichia coli.

CONCLUSION

Overall, this study isolated four bacteria strains with CDK activity to various horticultural plant pathogens, and revealed possible involvement of T6SS of Chryseobacterium cucumeris in antibacterial activity. These results provide valuable insight for potential application of CDK activity in biocontrol bacteria. © 2024 Society of Chemical Industry.

Enhanced Iturin A Production of Engineered Bacillus amyloliquefaciens by Knockout of Endogenous Plasmid and Rap Phosphatase Genes

Iturin A biosynthesis has garnered considerable interest, yet bottlenecks persist in its low productivity in wild strains and the ability to engineer Bacillus amyloliquefaciens producers. This study reveals that deleting the endogenous plasmid, plas1, from the wild-type B. amyloliquefaciens HM618 notably enhances iturin A synthesis, likely related to the effect of the Rap phosphatase gene within plas1. Furthermore, inactivating Rap phosphatase-related genes (rapC, rapF, and rapH) in the genome of the strain also improved the iturin A level and specific productivity while reducing cell growth. Strategic rap genes and plasmid elimination achieved a synergistic balance between cell growth and iturin A production. Engineered strain HM-DR13 exhibited an increase in iturin A level to 849.9 mg/L within 48 h, significantly shortening the production period. These insights underscore the critical roles of endogenous plasmids and Rap phosphatases in iturin A biosynthesis, presenting a novel engineering strategy to optimize iturin A production in B. amyloliquefaciens.

Microbial bioformulation: a microbial assisted biostimulating fertilization technique for sustainable agriculture

Addressing the pressing issues of increased food demand, declining crop productivity under varying agroclimatic conditions, and the deteriorating soil health resulting from the overuse of agricultural chemicals, requires innovative and effective strategies for the present era. Microbial bioformulation technology is a revolutionary, and eco-friendly alternative to agrochemicals that paves the way for sustainable agriculture. This technology harnesses the power of potential microbial strains and their cell-free filtrate possessing specific properties, such as phosphorus, potassium, and zinc solubilization, nitrogen fixation, siderophore production, and pathogen protection. The application of microbial bioformulations offers several remarkable advantages, including its sustainable nature, plant probiotic properties, and long-term viability, positioning it as a promising technology for the future of agriculture. To maintain the survival and viability of microbial strains, diverse carrier materials are employed to provide essential nourishment and support. Various carrier materials with their unique pros and cons are available, and choosing the most appropriate one is a key consideration, as it substantially extends the shelf life of microbial cells and maintains the overall quality of the bioinoculants. An exemplary modern bioformulation technology involves immobilizing microbial cells and utilizing cell-free filters to preserve the efficacy of bioinoculants, showcasing cutting-edge progress in this field. Moreover, the effective delivery of bioformulations in agricultural fields is another critical aspect to improve their overall efficiency. Proper and suitable application of microbial formulations is essential to boost soil fertility, preserve the soil's microbial ecology, enhance soil nutrition, and support crop physiological and biochemical processes, leading to increased yields in a sustainable manner while reducing reliance on expensive and toxic agrochemicals. This manuscript centers on exploring microbial bioformulations and their carrier materials, providing insights into the selection criteria, the development process of bioformulations, precautions, and best practices for various agricultural lands. The potential of bioformulations in promoting plant growth and defense against pathogens and diseases, while addressing biosafety concerns, is also a focal point of this study.

Engineering of PVA/PVP Hydrogels for Agricultural Applications

Hydrogels have gained significant popularity in agricultural applications in terms of minimizing waste and mitigating the negative environmental impact of agrochemicals. This review specifically examines the utilization of environmentally friendly, shapable hydrogels composed of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) in various casings for crop protection against different pests, fertilizing, and watering. To activate their effectiveness, PVA/PVP hydrogels were loaded with both hydrophilic and hydrophobic environmentally friendly pesticides, namely hydrogen peroxide (HP), the essential oil thymol, and urea as a fertilizer, either separately or in combination. This review covers various physical and chemical approaches used for loading, shaping, and controlling the release profiles of pesticides and fertilizers. Additionally, it explores the evaluation of the chemical composition, structure, classification, rheology, and morphology of the hydrogels as well as their impact on the thermal stability of the encapsulated pesticides and fertilizer, followed by biological tests. These hydrogels significantly contribute to the stabilization and controlled release of essential nutrients and biocides for plants, while maintaining excellent biocidal and fertilizing properties as well as sustainability characteristics. By shedding light on the latest insights into the concepts, applications, and results of these hydrogels, this review demonstrates their immense potential for widespread future use in agriculture.

Encapsulation of tannic acid in polyvinylidene fluoride mediated electrospun nanofibers and its antibiofilm and antibacterial activities

In the past 15 years or more, interest in polymer-mediated nanofibers (NFs), a significant class of nanomaterials, has grown. Although fibers with a diameter of less than 1 mm are frequently commonly referred to as NFs, and are typically defined as having a diameter of less than several hundreds of nanometers. Due to the increased antibiotic resistance of many diseases nowadays, NFs with antibacterial activity are quite important. A flexible technique for creating NFs with the desired characteristics is called electrospinning. This research article describes how to make electrospun NFs of tannic acid (TA) with polyvinylidene fluoride (PVDF) as the template. As a result, the absorbance of the obtained NFs has been raised without forming any additional peaks in the spectral ranges. The obtained NF has a gradual increase in intensity, and the FT-IR data show that the TA is present in the NFs. FE-SEM images show that the NFs are discovered to be completely bead-free. Since TA reduced the viscosity of the spinning solution while marginally increasing solution conductivity, PVDF NFs have a greater average fiber diameter (AFD) than NFs of TA with PVDF, which is likely a result of the TA solutions in it. The findings showed that TA greatly decreased S. aureus and E. coli's ability to attach. The acquired NFs created in this work may have significant potential for reducing the pathogenicity of S. aureus and E. coli as well as their ability to build biofilms.

Electrospinning Living Bacteria: A Review of Applications from Agriculture to Health Care

Living bacteria are used in biotechnologies that lead to improvements in health care, agriculture, and energy. Encapsulating bacteria into flexible and modular electrospun polymer fabrics that maintain their viability will further enable their use. This review will first provide a brief overview of electrospinning before examining the impact of electrospinning parameters, such as precursor composition, applied voltage, and environment on the viability of encapsulated bacteria. Currently, the use of nanofiber scaffolds to deliver live probiotics into the gut is the most researched application space; however, several additional applications, including skin probiotics (wound bandages) and menstruation products have also been explored and will be discussed. The use of bacteria-loaded nanofibers as seed coatings that promote plant growth, for the remediation of contaminated wastewaters, and in energy-generating microbial fuel cells are also covered in this review. In summary, electrospinning is an effective method for encapsulating living microorganisms into dry polymer nanofibers. While these living composite scaffolds hold potential for use across many applications, before their use in commercial products can be realized, numerous challenges and further investigations remain.

Electrospun tannin-rich nanofibrous solid-state membrane for wastewater environmental monitoring and remediation

Heavy metal, organic dyes, and bacterial contamination in water endanger human/animals' health, and therefore, the detection, adsorption, and capturing of contaminants are essential for environmental safety. Ligand-rich membranes are promising for sensors, adsorption, and bacterial decontamination. Herein, tannin (TA)-reinforced 3-aminopropyltriethoxysilane (APTES) crosslinked polycaprolactone (PCL) based nanofibrous membrane (PCL-TA-APTES) was fabricated via electrospinning. PCL-TA-APTES nanofibers possess superior thermal, mechanical, structural, chemical, and aqueous stability properties than the un-crosslinked membrane. It changed its color from yellowish to black in response to Fe^2+/3+ ions due to supramolecular iron-tannin network (FeTA) interaction. Such selective sensing has been noticed after adsorption-desorption cycles. Fe³⁺ concentration, solution pH, contact time, and ligand concentration influence FeTA coordination. Under optimized conditions followed by image processing, the introduced membrane showed a colorimetric linear relationship against Fe³⁺ ions (16.58 μM-650 μM) with a limit of detection of 5.47 μM. The PCL-FeTA-APTES membrane could restrain phenolic group oxidation and result in a partial water-insoluble network. The adsorption filtration results showed that the PCL-FeTA-APTES membrane can be reused and had a higher methylene blue adsorption (32.04 mg/g) than the PCL-TA-APTES membrane (14.96 mg/g). The high capture efficiency of nanocomposite against Fe³⁺-based S. aureus suspension than Fe³⁺-free suspension demonstrated that Fe³⁺-bounded bacterium adhered to the nanocomposite through Fe³⁺/TA-dependent biointerface interactions. Overall, high surface area, rich phenolic ligand, porous microstructure, and super-wetting properties expedite FeTA coordination in the nanocomposite, crucial for Fe^2+/3+ ions sensing, methylene blue adsorption-filtration, and capturing of Fe³⁺-bounded bacterium. These multifunctional properties could promise nanocomposite membrane practicability in wastewater and environmental protection.

Genomics as a potential tool to unravel the rhizosphere microbiome interactions on plant health

Intense agricultural practices to meet rising food demands have caused ecosystem perturbations. For sustainable crop production, biological agents are gaining attention, but exploring their functional potential on a multi-layered complex ecosystem like the rhizosphere is challenging. This review explains the significance of genomics as a culture-independent molecular tool to understand the diversity and functional significance of the rhizosphere microbiome for sustainable agriculture. It discusses the recent significant studies in the rhizosphere environment carried out using evolving techniques like metagenomics, metatranscriptomics, and metaproteomics, their challenges, constraints infield application, and prospective solutions. The recent advances in techniques such as nanotechnology for the development of bioformulations and visualization techniques contemplating environmental safety were also discussed. The need for development of metagenomic data sets of regionally important crops, their plant microbial interactions and agricultural practices for narrowing down significant data from huge databases have been suggested. The role of taxonomical and functional diversity of soil microbiota in understanding soil suppression and part played by the microbial metabolites in the process have been analyzed and discussed in the context of 'omics' approach. 'Omics' studies have revealed important information about microbial diversity, their responses to various biotic and abiotic stimuli, and the physiology of disease suppression. This can be translated to crop sustainability and combinational approaches with advancing visualization and analysis methodologies fix the existing knowledge gap to a huge extend. With improved data processing and standardization of the methods, details of plant-microbe interactions can be successfully decoded to develop sustainable agricultural practices.

Applications, challenges, and needs for employing synthetic biology beyond the lab

Synthetic biology holds great promise for addressing global needs. However, most current developments are not immediately translatable to 'outside-the-lab' scenarios that differ from controlled laboratory settings. Challenges include enabling long-term storage stability as well as operating in resource-limited and off-the-grid scenarios using autonomous function. Here we analyze recent advances in developing synthetic biological platforms for outside-the-lab scenarios with a focus on three major application spaces: bioproduction, biosensing, and closed-loop therapeutic and probiotic delivery. Across the Perspective, we highlight recent advances, areas for further development, possibilities for future applications, and the needs for innovation at the interface of other disciplines.

Recent advances in biodegradable matrices for active ingredient release in crop protection: Towards attaining sustainability in agriculture

Climate changes, emerging species of plant pests, and deficits of clean water and arable land have made availability of food to the ever-increasing global population a challenge. Excessive use of synthetic pesticides to meet ever-increasing production needs has resulted in development of resistance in pest populations, as well as significant ecotoxicity, which has directly and indirectly impacted all life-forms on earth. To meet the goal of providing safe, sufficient, and high-quality food globally with minimal environmental impact, one strategy is to focus on targeted delivery of pesticides using eco-friendly and biodegradable carriers that are derived from naturally available materials. Herein, we discuss some of the recent approaches to use biodegradable matrices in crop protection, while exploring their design and efficiency. We summarize by discussing associated challenges with the existing approaches and future trends that can lead the world to more sustainable agricultural practices.

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Providing food safety and security is critical for the growing global population.

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Crop yield is affected by various biotic and abiotic factors.

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Targeted/sustained delivery of agrochemicals reduces excessive use of pesticides.

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Nature-derived biodegradable materials curtail plant health and environmental harm.

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Biodegradable matrices hold promise for sustainable crop protection.

Fabrication of Electrospun Probiotic Functionalized Nanocomposite Scaffolds for Infection Control and Dermal Burn Healing in a Mice Model

The importance of microbiota paves the way to use microbial cells as medicines to treat pathobiomic diseases. This study reported the fabrication of probiotic (Enterococcus mundtii QAUEM2808)-functionalized nanocomposite scaffolds of poly(vinyl alcohol)/poly(vinylpyrrolidone)/glycerol via electrospinning. Scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis resolved the living composite structure and supported the encapsulation of E. mundtii throughout the nanostructured (318 ± 12 nm) fibers of bioscaffold membranes. The shelf life evaluation of 4-week-old samples supported that bioscaffolds showed an enhancement in probiotic survival count by 2.78 ± 0.10 log₁₀ colony-forming units (cfu) versus counterpart biodispersion. The swelling and antagonistic evaluation showed that a bioscaffold is degradable in a simulated wound fluid which is essential for activation of probiotic strains to antagonize infection-causing Gram-positive and Gram-negative pathogens. A second-degree contact burn was made on the dorsum of male BALB/c mice (n = 30). The wounds were left open for 2 days to mimic burn contamination, and the mice were randomized into negative (untreated), positive (silver sulfadiazine cream), vehicle (biodispersion and nanoscaffold), and experimental bioscaffold groups (n = 6/group). These treatments were applied on 2, 6, 10, and 14 days postburn. A comparative wound closure, histopathology, and wound microbial evaluation demonstrated that the bioscaffolds accelerate epithelialization, collagen deposition, and hair follicle formation, inhibit harmful bacteria, and provide interference benefits. In particular, the probiotic active bioscaffold membrane could serve as a novel candidate to control infections and speed up the healing of burn wounds.