Biochemical Engineering Journal最新文献

This study introduces an advanced electrochemical biosensor that utilizes MoS₂@CNT as an electrode material combined with a specific DNA probe to detect Salmonella Typhi rapidly and accurately. The sensor offers a broad detection range from 1.0 × 10⁻⁶ to 1.0 × 10⁻¹⁸ molL⁻¹ and boasts an exceptionally low limit of detection (LOD) of 1.0 × 10⁻²⁰ molL⁻¹ for the target bacterium. It demonstrates a detection range from 1.0 × 10⁴ to 1.0 × 10¹¹ CFUml⁻¹ in real samples, with a corresponding LOD of 1.0 × 10⁴ CFUml⁻¹. Rigorous testing against base mismatches and various bacterial strains confirms its specificity, ensuring reliable performance. Validated in real samples, the biosensor can accurately identify Salmonella Typhi in water and milk, achieving recoveries ranging from 92.95 % to 99.58 %. The exceptional performance of the biosensor is attributed to the MoS₂@CNT electrode material and the specific DNA recognition probe, which enhance electron transfer and reduce steric impedance. These improvements contribute to the sensor's enhanced sensitivity and specificity, making it a significant advancement in public health safety by providing a rapid and accurate tool for detecting Salmonella Typhi in food samples.

The technological potential of co-digesting bovine rumen waste (BRW) with brewery spent grain (BSG) is significant, offering enhanced biogas production and effective waste management. This study's findings demonstrate that the anaerobic digestion process becomes significantly more efficient when difficult to degrade BRW is combined with easily degradable BSG. The highest methane yield obtained in the mono-digestion of BRW was 127.11 NmL_CH4 g_VS⁻¹ with biodegradability of 33.89 % in inoculum to substrate ratio (ISR) 2, and for de BSG obtained was 304.18 NmL_CH4 g_VS⁻¹ with biodegradability of 68.26 % in ISR 4. The overall average obtained in co-digestion for volatile solids (VS) removal was 26.28 %, and the concentration of methane present in the biogas was 57.18 %. The VS removal efficiency and the increase in biogas and methane yield were directly proportional to the rise in ISR and the proportion of BSG in the mixture. Specifically, the ideal mix of 25 % BRW with 75 % BSG at ISR 4 resulted in a notable methane yield of 255.30 NmL_CH4 g_VS⁻¹. This process stabilizes digestion and significantly improves solids removal and methane concentration, making it a highly efficient solution for sustainable energy production and industrial waste management.

In recent years, 5-aminolevulinic acid (5-ALA) has attracted significant interest due to its roles as a photodynamic prodrug and an antiviral agent. In this study, we present a new approach using aconitase A from Escherichia coli Nissle 1917 (EcNAcnA), renowned for its exceptional activity and conjunction with ALA synthase from Rhodobacter capsulatus (RcALAS) to enhance 5-ALA production in an engineered chassis. Expression of EcNAcnA and RcALAS via dual plasmids led to a 59 % increase in 5-ALA yield, reaching up to 6.645 g/L. Diverse 5-ALA production levels were observed with different combinations of promoters and replication origins for both genes. Subsequently, an all-in-one plasmid with a high copy number, designated as RcNN, was introduced into the genomic engineering RcI strain. This resulted in the production of 24.5 g/L 5-ALA with a productivity of 0.907 g/L/h in a bioreactor under pH control and glucose feeding over 27 h. To the best of our knowledge, this is the first study to enhance 5-ALA biosynthesis by applying a superior aconitase variant from E. coli Nissle 1917, which enhances isocitrate production in the tricarboxylic acid (TCA) cycle and alleviates reactive oxygen species (ROS), thereby promoting 5-ALA accumulation effectively.

Traditional chromatography often faces issues such as high cost and insufficient selectivity, driving a continuous demand for improved technologies. Current chromatography primarily relies on single-ligand modes, and the methods for its performance optimization are gradually encountering limitations. This study validated the efficacy of integrating a second ligand into the system to boost chromatographic performance, focusing on hydrophobic charge-induction chromatography. Initially, optimal resin (4FF-MMI, 109 µmol/g resin) was targeted, with various densities of the second ligand (4FF-MMI⁺) assessed for performance enhancement, achieving optimal values at (110+11) µmol/g resin. Characterization, including Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Brunauer-Emmett-Teller, was conducted. Subsequently, Optimization effects under different pH, salt, and flow rate conditions were studied. Results showcase significant chromatographic enhancement with the second ligand. In the final phase, both 4FF-MMI and 4FF-MMI⁺ were utilized for human IgG separation from human serum, employing pH 8.0 and pH 7.0 as the loading pH, pH 5.0 as the elution pH, and a flow rate of 0.75 mL/min. Compared to 4FF-MMI, 4FF-MMI⁺ achieved 96.6 % purity and 91.6 % recovery, representing increases of 10.6 % and 20.4 %, respectively. Additionally, the resin with the second ligand exhibits commendable repeatability and stability. In conclusion, this study highlights the potential of adding a second ligand to improve chromatographic capabilities, offering a novel strategy to augment existing ligand libraries.

Enzymatic hydrolysis of polyethylene terephthalate (PET) waste is a compelling strategy for environmentally friendly recycling of a major pollutant. Here, we investigate the effects of surface charge point mutations both proximal and distal to the active site of the mesophilic PET-degrading enzyme IsPETase and the thermostable V3 variant with superior activity. The vicinal K95A mutation significantly inhibited IsPETase activity on mechanically processed PET powder. Conversely, this mutation significantly increased hydrolysis of PET powder in the V3 PETase. Activity of both enzymes on PET film was inhibited by the K95A mutation, highlighting complex interplay between mutation context and substrate morphology. Further installing the distal R132N and R280A surface charge mutations potentiated activity of V3 on all substrates tested. This variant afforded 100 % degradation of pre-processed bottle-grade PET powder in 3 days at 40^°C reaction temperature, a 3-fold improvement over IsPETase. Whilst reduction of positive charge on the PETase surface is known to reduce interaction with PET, molecular dynamics simulations suggest this can be offset by context-dependent modulation of active site flexibility, which differentially impacts both hydrolysis of morphologically distinct PET substrates and the concentration-dependent inhibition phenomenon observed for PETase.

There has been recent interest in using the β-galactosidase of Aspergillus oryzae to produce lactulose and fructosyl-galactooligosaccharides, for use as prebiotics. The success of the enzymatic process depends on the selectivities of the enzyme for the various transgalactosylation and hydrolysis reactions that occur in these systems, but the methods that have been used to date to express these selectivities are not adequate. In the current work, we demonstrate a method for determining the selectivity of the β-galactosidase of A. oryzae in two case studies done with literature data: (1) the production of lactulose from a mixture of lactose and fructose and (2) the production of fructosyl-galactooligosaccharides (fGOS) from lactulose. In the first case study, we demonstrate that the enzyme has a 4- to 5-fold preference for producing GOS over lactulose when an equimolar mixture of fructose to lactose is used, but that the selectivity for producing lactulose increases as the initial fructose to lactose molar ratio increases. In the second case study, we show that the enzyme has about a 1.5-fold preference for producing fGOS4 and fGOS5 over the initial transgalactosylation product, fGOS3. The selectivities that we determine in our work will be important parameters for time-based models used to guide the development and optimization of processes for the production of lactulose and fructosyl-galactooligosaccharides as prebiotics.

This research is critically important for large-scale poultry farming, where vigilant monitoring is necessary to assess nutrient levels in poultry feed. Detecting cerium in poultry feed through colorimetric techniques is crucial for evaluating nutrient intake, feed quality, animal health, and broader environmental impacts. This study significantly contributes to ongoing research and monitoring efforts, aiding in maintaining an optimal mineral balance and enhancing chicken quality and overall poultry performance. The study utilized Alizarin Red dye (AR), both individually and in combination with Eriochrome Black T (EBT), to identify the presence of cerium ions. Various experimental conditions such as pH, concentration, temperature, and specificity were thoroughly examined. The UV-Vis absorption spectra indicated that the average minimum detectable limit for cerium ions is approximately 5 ppm, with a detection range of 0.2–3 mM. Additionally, a cost-effective paper-based sensor and a portable colorimetric method for detecting cerium ions were innovatively designed. This paper-based sensor ensures precise detection at room temperature, demonstrating high sensitivity and selectivity. The detection system was integrated with smart devices, enabling the swift capture of Red, Green, and Blue (RGB) values for practical real-time applications. This integration allows for rapid on-site identification of cerium ions. The introduction of this affordable, accurate, and portable colorimetric method for monitoring cerium ions represents a promising advancement in developing accessible tools within this field.

Liver cancer is one of the most common cancers and the third leading cause of cancer deaths worldwide. Diagnosis and screening for liver cancer rely on the alpha-fetoprotein (AFP) biomarker. This study aimed to pioneer a novel assay for AFP detection utilizing a tri-part split-luciferase system in conjunction with nanobodies targeting AFP. The strategy involved fusing anti-AFP nanobodies P5 and P15 to the split-nanoluciferase components β9 and β10, respectively. Upon binding to AFP and in the presence of the third nanoluciferase component Δ11S, the proximity-induced reassembly of split-nanoluciferase components triggers luciferase activation and luminescence emission. Following expression in a bacterial system, purification, and assay implementation, the developed assay exhibited high sensitivity in detecting AFP within a linear range of 1–20 ng/ml, with a Limit of Detection (LOD) of 0.5 ng/ml. The assay results were in line with those obtained from ELISA, indicating its efficiency. This study highlights the specificity of the homogenous assay developed with nanobodies for AFP, offering a reliable and user-friendly test for AFP detection.

The accumulation of glyphosate during its application in agriculture and its toxicity seriously threaten ecosystems and human health. Currently, glyphosate residual contamination is mainly accomplished through bioremediation techniques based on enhanced microbial degradation activity. However, there are drawbacks, such as poor environmental adaptability of strains and low degradation efficiency. Therefore, in this study, an efficient glyphosate-degrading strain, Pseudomonas alcaligenes Z1–1, was isolated from herbicide-contaminated environments and was capable of completely degrading glyphosate at a concentration of 200 mg/L within 7 days. Kinetics analysis showed that glyphosate degradation was concentration-dependent, with a maximum tolerant concentration of 800 mg/L. Mass spectrometric analysis indicated that AminoMethylPhosphonic acid (AMPA) was the predominant intermediate produced in the degradation pathway of glyphosate, revealing that glyphosate destruction began with breaking the C-N bond. Whole genome sequencing identified the key genes potentially involved in glyphosate degradation, including the thiO, glpA, aroA, soxB, and argA genes. Furthermore, in contrast to the majority of the metabolic pathways previously reported for glyphosate degradation via glyphosate oxidoreductase, the breaking of the C-N bond was primarily catalyzed by glycine oxidase. Overall, this research provides novel insights into the mechanisms of glyphosate degradation, offering valuable degradation enzyme resources for future applications.

Swarming migration is observed in flagellated bacteria on wet surfaces. As the secreted biosurfactant hydrates, friction between the cell and the wet surface is reduced, and weak flagellar movement appears to be a significant force for cell translocation. Developing an artificial swarming control method could greatly aid in establishing techniques for biofilm inhibition and detachment. In this study, the effect of forced cell vibration by an alternating current electric field (ACEF) on swarming motility was investigated using the serrawettin W1-producing Serratia marcescens strain. At frequencies close to the natural frequencies of microbial cells (12 MHz), swarming motion was effectively enhanced in biosurfactant-producing S. marcescens, but not in non-surfactant-producing Escherichia coli or non-flagellated Staphylococcus aureus. Electric field-assisted cell migration was significantly induced under swarming conditions with low friction resistance between the cell and gel surface. This finding suggests a direction for developing strategies to regulate biofilm formation and detachment using ACEF-assisted oscillation of cells attached to surfaces.