Multiple Potential Applications Research Articles

Enhancement in capacitive performance of Co3O4 with MnTiO3 via composite (MnTiO3/Co3O4) strategy developed by ultrasonication route

The specific surface area, conductivity and cyclic stability of nanomaterials significantly impact a pseudocapacitor electrode's performance. The Co3O4 is economically viable and widely available but has limited surface area and conductivity. However, MnTiO3 has a greater surface area and exhibits superior ion conductivity, resulting in better specific capacitance (Cs). Herein, a novel MnTiO3/Co3O4 nanocomposite is manufactured to enhance the properties of Co3O4 using an ultrasonication technique for application in supercapacitors. Several analytical methods were utilized to examine synthesized materials' textural, structural and morphological characteristics. The MnTiO3/Co3O4 nanocomposite demonstrated notable Cs of 1534.67 F/g, specific energy (SE, 64.05 Wh/kg) and specific power (SP, 274.1 W/kg) at current density (Cd) of 1 A/g in 2.0 M KOH solution, according to electrochemical experiments. Additionally, after 5000th cycles, the nanocomposite exhibits excellent cyclic stability than pristine materials. This study not only showcases the significant capabilities of the commercially accessible MnTiO3/Co3O4 nanocomposite but also presents a novel approach for developing cost-effective, high-performing composite materials with multiple potential applications in the energy field.

Couple-stress nanofluid flow comprising gyrotactic microbes subject to convective boundary conditions: Numerical solution

Couple-stress nanofluids have multiple potential applications in numerous industrial and engineering sectors, such as energy production, medical diagnostics, thermal control systems, and the aerospace industry. Couple-stress nanofluids have the ability to improve the heat exchange properties and elevate the performance of nuclear power plants, solar panels, and other renewable energy sources. Therefore, in the current analysis, a non-homogeneous nanofluid model is considered to examine the non-Newtonian Casson nanofluid flow across a prolonging sheet. The flow has been studied under the significance of generalized Fourier’s and Fick’s laws, convective boundary conditions, and the heat source/sink. The modeled equations are simplified into a dimensionless lowest-order system of ordinary differential equations by using similarity transformation. The numerical outcomes are achieved by using the “ND-Solve” approach. It has been noticed that the energy field decreases because of the Prandtl number’s impacts, whereas it increases with the increase in the heat radiation parameter. The couple-stress nanoliquid’s velocity decreases vs increasing values of the magnetic field and mixed convection parameter. The influence of thermal relaxation and couple-stress parameters falls off the energy field. Furthermore, the intensifying effect of Rayleigh number and buoyancy ratio increases the fluid temperature.

Multifunctional graphene/Ti3C2Tx MXene aerogel inlaid with Ni@TiO2 core-shell microspheres for high-efficiency electromagnetic wave absorption and thermal insulation

The demand for high-performance electromagnetic wave absorbing (EMA) materials featured with strong attenuation ability, extended absorption bandwidth and ultralight property is imperative yet remains challenging. Herein, a three-dimensional hierarchically porous reduced graphene oxide (rGO)/Ti3C2Tx MXene aerogel embedded with Ni@TiO2 core–shell microspheres was prepared via directional freeze-drying followed by a mild annealing process. The divergence in structure and multicomponent dielectric/magnetic features bring about optimized impedance matching characteristic, multiple polarization and loss pathways, collectively contributing to the excellent absorption performance. As a result, the Ni@TiO2/MXene/rGO (NTMRG-2) aerogel exhibits optimized EMA capability with a maximal effective absorption bandwidth (EABmax) of 6.48 GHz at a lower loading level of 5 wt% in the supporting matrix, covering the whole Ku band. Additionally, it achieves a minimum reflection loss (RLmin) of −71.4 dB with a matching thickness of 2.04 mm. Moreover, the aerogel also exhibits an ultra-light density of 5.58 mg cm−3, superior thermal insulation capacity (close to air) and hydrophobicity, underscoring its potential for multiple applications in various scenarios.

Abstract 5811: Ultralong CDR3 engineered interleukin-15 antibody fusion for T and NK cell expansion

Abstract Interleukin (IL)-15 is a promising immunotherapeutic cytokine for cancer treatment because it can stimulate the proliferation and cytotoxicity of CD8+ T lymphocytes and nature killer (NK) cells, similar to the action of IL-2, which has been used to treat metastatic melanoma and renal cancer. IL-15 may have improved pharmacologic properties over IL-2 because it doesn’t cause vascular leak syndrome or stimulate regulatory T cells. However, IL-15 is difficult to express as a stable soluble protein and has a short half-life in vitro and in vivo. To solve the problem, we designed an IL-15 ultralong CDR3 humanized bovine antibody fusion. Bovine ultralong CDR3 antibodies have a unique “stalk and knob” structure in which two antiparallel β-strands support a disulfide bonded knob protruding out of the antibody surface and forms a mini antigen binding domain. By replacing the knob domain with IL-15, we have created a chimeric CDR3-IL-15 IgG which functions as IL-15 in vitro and in vivo but can be easily produced in mammalian cells with increased stability. Thus, the CDR3 can stabilize IL-15 in the absence of its high affinity receptor α (Rα) chain. Furthermore, as IL-15 utilizes Rα for increased trans signaling to the receptor β and γ subunits, one variant candidate (CDR3-IL-15_Rα) was produced by co-expressing Rα sushi domain with the chimeric IgG. Both constructs have been demonstrated to be highly active in stimulating proliferation of NK cells and CD8+ T cells in vitro as well as in stimulating proliferation of NK cells and CD8+ T cells in rats and non-human primates (NHP). Although the CDR3-IL-15_Rα exhibited higher in vitro signaling activity than CDR3-IL-15, both were equally potent in stimulating the proliferation of NK cells and CD4+ and CD8+ T cells in NHP without any immunogenicity detected. Moreover, in vivo studies in NHP indicated that CDR3-IL-15 acted faster than CDR3-IL-15_Rα in stimulating the proliferation of these lymphocytes. CDR3-IL-15 is the first thermodynamically stabilized variant of IL-15 produced in the absence of its Rα chain, is highly active in vivo, and has multiple potential cancer applications as an T and NK cell stimulating agent. Citation Format: Ruiqi Huang, Duncan McGregor, Vaughn Smider. Ultralong CDR3 engineered interleukin-15 antibody fusion for T and NK cell expansion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5811.

Magnetically driven capsules with multimodal response and multifunctionality for biomedical applications

Untethered capsules hold clinical potential for the diagnosis and treatment of gastrointestinal diseases. Although considerable progress has been achieved recently in this field, the constraints imposed by the narrow spatial structure of the capsule and complex gastrointestinal tract environment cause many open-ended problems, such as poor active motion and limited medical functions. In this work, we describe the development of small-scale magnetically driven capsules with a distinct magnetic soft valve made of dual-layer ferromagnetic soft composite films. A core technological advancement achieved is the flexible opening and closing of the magnetic soft valve by using the competitive interactions between magnetic gradient force and magnetic torque, laying the foundation for the functional integration of both drug release and sampling. Meanwhile, we propose a magnetic actuation strategy based on multi-frequency response control and demonstrate that it can achieve effective decoupled regulation of the capsule’s global motion and local responses. Finally, through a comprehensive approach encompassing ideal models, animal ex vivo models, and in vivo assessment, we demonstrate the versatility of the developed magnetic capsules and their multiple potential applications in the biomedical field, such as targeted drug delivery and sampling, selective dual-drug release, and light/thermal-assisted therapy.

Genome sequence of thermophilic cellulolytic actinobacterium Thermobifida fusca strain UPMC 901 producing thermostable cellulases.

Thermophilic cellulolytic bacteria producing thermostable cellulase have multiple potential industrial and biotechnological applications. In this study, we sequenced the genome of Thermobifida fusca UPMC 901 by using nanopore sequencing technology with 100 % genome coverage. The represented genome is 3.76 Mb with a G + C content of 67.4 %. The genome is composed of 1 scaffold with 3207 protein-coding genes. The results indicated that the genome of the Thermobifida fusca gene encodes at least 112 genes for carbohydrate-active enzymes. Of these genes, 40 glycoside hydrolases (GHs), 36 glycosyl transferases (GTs), 22 carbohydrate-binding modules (CBMs), 9 carbohydrate esterases (CEs), 3 polysaccharide lyases (PL) and 2 auxiliary activity (AAs) which refer to as lytic polysaccharide monooxygenase (LPMO), gene encoding the copper-dependent enzymes that catalyse oxidative cleavage of recalcitrant crystalline cellulose, were identified. In addition, two new functional genes, amylo-α-1,6 glucosidase and endo-α-1,4-mannosidase were also detected in the T. fusca genome. This study represented the ninth genome of the T. fusca and the cellulase genes identified will facilitate the exploration of potential sources for industrial and agricultural applications.

Second life of recycled graphite for sustainable production of multilayer graphene related materials with multiple potential applications

A sustainable route to obtain graphene oxide (GO) and reduced graphene oxide (rGO) with highly competitive properties through the utilization of graphite recycled from spent vehicle's lithium-ion batteries is described. As compared with previous works, our precursor material is representative of a larger-scale recycling procedure, involves the processing of both cathodic and anodic materials, and concerns a larger number of batteries operated in diverse conditions. The morphology, chemical features, structure, and conductivity of the samples have been thoroughly investigated. Results obtained from complementary characterization techniques reveal the correct formation of GO and rGO samples from the recycled graphites. Electrical measurements show that the conductivity of our GO and rGO samples are very similar or even larger than those reported for samples obtained from high-purity natural graphite. These results indicate that our strategy is able to produce good-quality GOs and rGOs with potential applications in different fields, contributing to the circular economy and the recyclability of discarded wastes.

Optimization of welan gum extraction and purification using lysozyme and alkaline protease.

Welan gum, a natural polysaccharide produced by Sphingomonas sp. ATCC 31555, has attracted considerable attention in the scientific community due to its desirable properties. However, challenges, such as high viscosity, residual bacterial cells, carotenoids, and protein complexation, hinder the widespread application of welan gum. In this study, we established a method for the extraction and purification of welan gum using a synergistic approach with lysozyme and alkaline protease. Lysozyme hydrolysis conditions were optimized by applying response surface methodology, and the best results for bacterial cell removal were achieved at 11 000 U/g, 44°C, and pH 9 after 3h of treatment. Subsequently, we evaluated protein hydrolysis through computer simulation and identified alkaline protease as the most suitable enzyme. Through experimental investigations, we found that the optimal conditions for alkaline protease hydrolysis were 7500 U/g, 50°C, pH 10, and 600rpm. These conditions resulted in a sugar recovery rate of 76.1%, carotenoid removal rate of 89.5%, bacterial removal rate of 95.2%, and protein removal rate of 87.3% after 3h of hydrolysis. The purified welan gum exhibited high transparency and purity. Structural characterization and antioxidant activity evaluation revealed that enzymatically purified welan gum has potential application prospects. Our study provides valuable insights into the optimal method for the enzymatic extraction and purification of welan gum. Such a method is conducive to the development of the multiple potential applications of welan gum. KEY POINTS: • A novel process for the synergistic purification of welan gum using lysozyme and alkaline protease was established. • In silico virtual digestion was employed to select the purification enzyme. • Welan gum with high transparency and purity was obtained.

Identification and Characterization of a Predominant Hydrophobin in the Edible Mushroom Grifola frondosa.

Hydrophobins (HFBs) are a group of small, secreted amphipathic proteins of fungi with multiple physiological functions and potential commercial applications. In this study, HFB genes of the edible mushroom, Grifola frondosa, were systematically identified and characterized, and their transcriptional profiles during fungal development were determined. In total, 19 typical class I HFB genes were discovered and bioinformatically analyzed. Gene expression profile examination showed that Gf.hyd9954 was particularly highly upregulated during primordia formation, suggesting its major role as the predominant HFB in the lifecycle of G. frondosa. The wettability alteration profile and the surface modification ability of recombinant rGf.hyd9954 were greater than for the Grifola HFB HGFII-his. rGf.hyd9954 was also demonstrated to form the typical class I HFB characteristic-rodlet bundles. In addition, rGf.hyd9954 was shown to possess nanoparticle characteristics and emulsification activities. This research sheds light on the regulation of fungal development and its association with the expression of HFB genes.

Broadband Near-Infrared Sr3Al9.8SiO20:0.2Cr Phosphor Realized by Crystallographic Site Engineering.

Broadband near-infrared (NIR) phosphor-converted devices play a vital role in emerging applications of imaging, medicine, agriculture, etc. Herein, a series of economical broadband NIR-emitting Sr3Al10-xSiO20:xCr (SASO:xCr) phosphors with tunable bandwidths and emission peaks were realized by tailoring the Cr3+ doping concentration. The optimal Sr3Al9.8SiO20:0.2Cr (SASO:0.2Cr) phosphor exhibits a broadband emission with full width at half-maximum ∼ 140 nm, and the internal/external quantum efficiency and thermal stability of the SASO:0.2Cr were measured to be 68%/37% and 77%@380 K, respectively. An NIR phosphor-converted light-emitting diode (NIR pc-LED) device was fabricated by combining a blue LED chip with the SASO:0.2Cr phosphor. The applications of NIR pc-LED on plant growth promotion, night vision, and medical imaging were demonstrated. We reported an economical broadband NIR phosphor with multiple potential applications and highlighted the crystallographic site engineering strategy to explore broadband phosphors based on aluminates.

Robust Piezoelectric Biomolecular Membranes from Eggshell Protein for Wearable Sensors.

Flexible and wearable devices are drawing increasing attention due to their promising applications in energy harvesting and sensing. However, the application of wearable devices still faces great challenges, such as flexibility, repeatability, and biodegradability. Biopiezoelectric materials have been regarded as favorable energy-harvesting sources due to their nontoxicity and biocompatibility. Here, a wearable and biodegradable sensor is proposed to monitor human activities. The proposed sensor is fabricated via a low-cost, facile, and scalable electrospinning technology from nanofibers composed of eggshell membranes mixed with polyethylene oxide. It is shown that the sensor exhibits excellent flexibility, outstanding degradability, and mechanical stability over 3000 cycles under periodic stimulation. The device displays multiple potential applications, including the recognition of different objects, human motion monitoring, and active voice recognition. Finally, it is shown that the composite nanofiber membrane has good degradability and breathability. With excellent sensing performance, environmental friendliness, and ease of processing, the eggshell membrane-based sensor could be a promising candidate for greener and more environmentally friendly devices for application in implantable and wearable electronics.

Increasing Chemical Diversity of B2 N2 Anthracene Derivatives by Introducing Continuous Multiple Boron-Nitrogen Units.

Increasing the chemical diversity of organic semiconductors is essential to develop efficient electronic devices. In particular, the replacement of carbon-carbon (C-C) bonds with isoelectronic boron-nitrogen (B-N) bonds allows precise modulation of the electronic properties of semiconductors without significant structural changes. Although some researchers have reported the preparation of B2 N2 anthracene derivatives with two B-N bonds, no compounds with continuous multiple BN units have been prepared yet. Herein, we report the synthesis and characterization of a B2 N2 anthracene derivative with a BNBN unit formed by converting the BOBN unit at the zigzag edge. Compared to the all-carbon analogue 2-phenylanthracene, BNBN anthracene exhibits significant variations in the C-C bond length and a larger highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap. The experimentally determined bond lengths and electronic properties of BNBN anthracene are confirmed through theoretical calculations. The BOBN anthracene organic light-emitting diode, used as a blue host, exhibits a low driving voltage. The findings of this study may facilitate the development of larger acenes with multiple BN units and potential applications in organic electronics.

Increasing Chemical Diversity of B2N2 Anthracene Derivatives by Introducing Continuous Multiple Boron‐Nitrogen Units

AbstractIncreasing the chemical diversity of organic semiconductors is essential to develop efficient electronic devices. In particular, the replacement of carbon‐carbon (C−C) bonds with isoelectronic boron‐nitrogen (B−N) bonds allows precise modulation of the electronic properties of semiconductors without significant structural changes. Although some researchers have reported the preparation of B2N2 anthracene derivatives with two B−N bonds, no compounds with continuous multiple BN units have been prepared yet. Herein, we report the synthesis and characterization of a B2N2 anthracene derivative with a BNBN unit formed by converting the BOBN unit at the zigzag edge. Compared to the all‐carbon analogue 2‐phenylanthracene, BNBN anthracene exhibits significant variations in the C−C bond length and a larger highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap. The experimentally determined bond lengths and electronic properties of BNBN anthracene are confirmed through theoretical calculations. The BOBN anthracene organic light‐emitting diode, used as a blue host, exhibits a low driving voltage. The findings of this study may facilitate the development of larger acenes with multiple BN units and potential applications in organic electronics.

Protein/Protein and Quantum Dot/Protein Organization in Sequential Monolayer Materials Studied Using Resonance Energy Transfer

Controlled junctions of proteins and nanomaterials offer multiple potential applications in the further construction of nanobiodevices. One of the possible junction types is a set of sequential monolayers of various components deposited on a given substrate. The advantage of such an organization is its high sensitivity, resulting from a huge surface covered by molecules or particles. What is more, the molecules/particles adsorbed on a substrate might be easier to handle than the assay in a cuvette. For further application, there should be crosstalk between monolayers; this is defined by the type of individuals forming a complex system. Here, we are studying, using mainly confocal microscopy and FLIM imaging, crosstalk through resonance energy transfer. The sequential monolayers of fluorescent proteins and CdTe quantum dots were deposited on a convenient substrate, a polyvinylidene difluoride membrane. First, we found that the degree of coverage is lower in the second monolayer. Hence, by manipulating the order of deposition, we obtained a system with a varied yield of resonance energy transfer with a donor excess or an acceptor excess. For a deeper understanding of the energy transfer and its limitations in this system influencing the assay pursuit, we utilized Monte Carlo computation. We found that, indeed, the distance between the monolayers, as well as the degree of coverage, is crucial. With the results of the simulation, we might estimate the relative degree of coverage in our sequential monolayers. We also found that in quantum-dots/protein-composed systems, the yield is stronger than predicted by Monte Carlo simulation. Hence, there should be protein reorientation on the nanoparticle surface, leading to such an effect. Finally, we showed that the yield of resonance energy transfer may be modulated by the external application of poly-L-lysines. These chemicals influenced QD fluorescence but not protein fluorescence and might be used, therefore, as a trigger or a switch in nanobiodevices employing those types of sequential monolayers.

Review of qualification and modeling for radiation-induced polymer degradation

Polymeric materials have multiple potential applications in nuclear power reactors including advanced and small modulus reactors, in addition to their extensive usage in safety electronic cables in the existing light water reactors. Through the qualification programs, knowledge accumulates about the polymer degradation kinetics under gamma-irradiation environment to facilitate the development of service-life predictive models. This paper aims to promote mechanistic-based predictability as a new approach to the qualification of polymeric components. Reviewed in this article are the current qualification standards and procedures, the current understandings of the degradation mechanisms, and kinetic models applicable to accelerated experiments for qualification.

Knowledge Graphs and Their Applications in Drug Discovery.

Knowledge graphs represent information in the form of entities and relationships between those entities. Such a representation has multiple potential applications in drug discovery, including democratizing access to biomedical data, contextualizing or visualizing that data, and generating novel insights through the application of machine learning approaches. Knowledge graphs put data into context and therefore offer the opportunity to generate explainable predictions, which is a key topic in contemporary artificial intelligence. In this chapter, we outline some of the factors that need to be considered when constructing biomedical knowledge graphs, examine recent advances in mining such systems to gain insights for drug discovery, and identify potential future areas for further development.

Advancements in total knee arthroplasty kinematics: 3D implant computer aided design model creation through X-ray or fluoroscopic images

Background3D-to-2D fluoroscopic registration is a popular and important step for analyzing total-knee-arthroplasty weight-bearing kinematics. Unfortunately, in vivo analyses using these techniques cannot be completed if the associated computer-aided design implant models are not available. This study introduces a novel method that enables the accessible computation of knee replacement patients' kinematics from fluoroscopy, achieved through the reconstruction of 3-dimensional knee component models using a limited set of 2-dimensional X-ray or fluoroscopic images. MethodsThe proposed non-rigid morphing algorithm, based on the coherent point drift algorithm, scales and transforms the shape of the template model to fit with the silhouette of the corresponding fluoroscopic images without changing the structure of the knee implant. While a greater number of fluoroscopic images can lead to higher accuracy, our study utilizes only 4 images. FindingsThe morphed models show excellent results in comparison with known models with a 0.52 mm average root-mean-square error and a 2.82 mm largest source error for 17 tested knee models of various implant types. The proposed algorithm also enables direct output of patient kinematics using fluoroscopy, with an average error of only 0.54 ± 0.42 mm for femorotibial contact and 0.86 ± 0.34 degrees for axial rotation. InterpretationA novel methodology was introduced to overcome common 3-dimentional to 2-dimensional registration limitations by recreating entire families of 3 dimensional models from a limited number of fluoroscopic images for both cruciate-retaining and posterior-stabilized knee replacement implants. Our algorithm has demonstrated high levels of accuracy with multiple potential extended applications.

Visible Light-Activated Ultralong-Lived Triplet Excitons of Carbon Dots for White-Light Manipulated Anti-Counterfeiting.

Room temperature phosphorescence (RTP) has emerged as an interesting but rare phenomenon with multiple potential applications in anti-counterfeiting, optoelectronic devices, and biosensing. Nevertheless, the pursuit of ultralong lifetimes of RTP under visible light excitation presents a significant challenge. Here, new phosphorescent materials that can be excited by visible light with record-long lifetimes are demonstrated, realized through embedding nitrogen doped carbon dots (N-CDs) into a poly(vinyl alcohol) (PVA) film. The RTP lifetime of the N-CDs@PVA film is remarkably extended to 2.1s excited by 420nm, representing the highest recorded value for visible light-excited phosphorescent materials. Theoretical and experimental studies reveal that the robust hydrogen bonding interactions can effectively reduce the non-radiative decay rate and radiative transition rate of triplet excitons, thus dramatically prolong the phosphorescence lifetime. Notably, the RTP emission of N-CDs@PVA film can also be activated by easily accessible low-power white-light-emitting diode. More significantly, the practical applications of the N-CDs@PVA film in state-of-the-art anti-counterfeiting security and optical information storage domains are further demonstrated. This research offers exciting opportunities for utilizing visible light-activated ultralong-lived RTP systems in a wide range of promising applications.

Cortisol in deciduous tooth tissues: A potential metric for assessing stress exposure in archaeological and living populations

ObjectiveCortisol is a glucocorticoid hormone produced by the hypothalamic-pituitary-adrenal axis that is regularly assessed in modern human and non-human populations in saliva, blood, and hair as a measure of stress exposure and stress reactivity. While recent research has detected cortisol concentrations in modern and archaeological permanent dental tissues, the present study assessed human primary (deciduous) teeth for cortisol concentrations. Materials and MethodsFifty-one dentine and enamel samples from nine modern and 10 archaeological deciduous teeth were analyzed for cortisol concentrations via enzyme-linked immunosorbent assay (ELISA). ResultsDetectable concentrations of cortisol were identified in 15 (of 32) dentine and 8 (of 19) enamel samples coming from modern and archaeological deciduous teeth. ConclusionsThis study is the first known analysis of cortisol from deciduous dental tissues, demonstrating the potential to identify measurable concentrations. SignificanceThe ability to analyze deciduous teeth is integral to developing dental cortisol methods with multiple potential future applications, including research on the biological embedding of stress in the skeleton. This study marks a key step in a larger research program to study stress in primary dentition from living and archaeological populations. LimitationsMultiple samples generated cortisol values that were not detectable with ELISA. Minimum quantities of tissue may be required to generate detectable levels of cortisol. Suggestions for Further ResearchFuture research should include larger sample sizes and consideration of intrinsic biological and extrinsic preservation factors on dental cortisol. Further method validation and alternative methods for assessing dental cortisol are needed.

Insights into the Unusual Activity of a Novel Homospermidine Synthase with a Promising Application to Produce Spermidine.

Spermidine is a naturally occurring polyamine with multiple biological activities and potential food and agricultural applications. However, sustainable and scalable spermidine production has not yet been attained. In this study, a homospermidine synthase (HSS) from Pseudomonas frederiksbergensis (PfHSS) capable of catalyzing the synthesis of spermidine from 1,3-diaminopropane and putrescine was identified based on multiple sequence alignment using Blastochloris viridis HSS (BvHSS) as a template. The optimal reaction pH and temperature for purified PfHSS were determined to be 8.5 and 45 °C, respectively, and K+ was able to promote the enzyme activity. Further analysis of the structural and functional relationships through molecular docking and molecular dynamics simulation indicates that glutamic acid at position 359 is the essential residue for the enzyme-catalyzed synthesis of spermidine. The whole-cell catalytic reaction yielded 1321.4 mg/L spermidine and 678.2 mg/L of homospermidine. This study presents a novel, promising, and sustainable biological method for producing spermidine.