Preparative Biochemistry & Biotechnology最新文献

The cyanobacterial strain BTA-330 was evaluated for its potential to produce exopolysaccharides (EPS) under nitrogen-deprived photoautotrophic conditions. The strain was initially identified through a polyphasic approach as Desmonostoc sp., BTA-330. The strain depicted biomass concentration of 1.23 g/L and total EPS of 367.87 ± 5.4 mg L^-1 in 30 days with capsular-EPS (CPS) and released-EPS (RPS) of 218.67 ± 2.5 and 149.2 ± 2.9 mg L^-1, respectively. Biomass composition analysis (in % w/w, DCW) showed total protein of 34% with 26.02% of total proteins comprising phycobiliproteins, followed by carbohydrates (32%), lipids (16%), nucleic acid (8%), other pigments (1.7%), and ash (7%). Kinetic studies revealed both CPS and RPS as secondary metabolites with maximum accumulation during the stationary phase of growth. The analysis of EPS composition showed abundant carbohydrate content of 80% (w/w, dry cell weight), followed by protein and nucleic acids. The subsequent characterization of both EPS using SEM, FTIR, and rheometer revealed the morphology, distinct functional groups, and their pseudoplastic behaviors, respectively. Further analysis demonstrated significantly high flocculating rate (39.4 ± 1.3 to 51.78 ± 1.3), DPPH scavenging (37.74 ± 1.5 to 39.76 ± 1.3), and hydroxyl ion scavenging (57.46 ± 1.2 to 69.53 ± 1.2) activities. Thus, Desmonostoc sp. BTA-330 is a unique source of EPS with potential applications in the food and pharma industries.

Microalgae-derived extracellular polysaccharides (EPSs) have emerged as a promising biological macromolecule for its application in pharmaceutical and biotechnological fields due to its diverse physicochemical and biological activities. In this study, an isolated microalgae (Asterarcys quadricellulare) was cultured in photobioreactor under the light condition by maintaining 14:10 photoperiod to produce EPSs. The yield of EPSs was found 0.392 ± 0.027 gL^-1. The biochemical analysis of extracted EPSs had shown the presence of uronic acid (0.42 ± 0.05%), phosphate (0.312 ± 0.013%), sulfate (0.531 ± 0.04%), and carbohydrates (60.33 ± 0.02%) containing glucose and galactose with a ratio of 3.24:1. FTIR analysis of EPSs revealed characteristic glycosidic bond between sugar monomer at 880 and 834 cm^-1. Therefore, extracted EPS was a complex heteropolysaccharide structure. Surface morphology of EPSs revealed the presence of a large number of symmetrical and regular filamentous repeating units. XRD analysis had shown the crystalline nature of extracted EPSs with crystallinity index of 51.73%. Antimicrobial activity of EPSs was evaluated against Bacillus subtilis (gram positive) and Escherichia coli (gram negative) bacteria. Escherichia coli had showed 46.67 ± 0.002% growth inhibition and 33.3 ± 2.5% (P < 0.01) reduction in the viable cell count compared to the negative control. Results demonstrated the promise of microalgal EPSs in the biotechnology and pharmaceutical sectors for selective antimicrobial application.

The application of cold-adapted enzymes in biocatalysis offers significant industrial advantages, particularly for processes that require high efficiency at low temperatures. However, their practical use is often hindered by their poor thermal stability and limited reusability. In this study, psychrophilic lipase Glalip03 from Glaciozyma antarctica PII2 was immobilized on Seplite LX120, a cost-effective macroporous resin, via physical adsorption. Comprehensive biophysical analyses, including Scanning Electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) surface area analysis, confirmed successful immobilization. The immobilized Glalip03 displayed significantly improved thermal stability, maintaining over 50% activity at 55 °C, and retained more than 50% of its initial catalytic activity after five consecutive cycles. The adsorption equilibrium data best fit the Jossens isotherm model, indicating a heterogeneous multilayer adsorption process. Furthermore, the enzyme showed enhanced tolerance to selected organic solvents and maintained robust storage stability at both 4 °C and ambient temperatures. These findings demonstrate that Seplite LX120 is an effective carrier for cold-active lipase immobilization, offering a simple and scalable strategy for enhancing enzyme stability, reusability, and solvent compatibility. The improved biocatalyst holds strong potential for industrial applications in detergents, food processing, flavor synthesis, and cosmetics.

Salvia hispanica L. species, also known as "Chia," is an annual plant belonging to the Lamiaceae family. Chia seeds are of great importance in the daily diet due to their high quality components, such as proteins, carbohydrates, fibers, minerals, antioxidants and fats. In the present study, optimum maceration conditions were determined for preparation of chia seed extracts with high total phenolic compound content by experimental design approach. For this purpose, a response surface methodology type known as Box-Behnken design was applied. Ethanol concentration of the extraction solvent, extraction time and solvent volume were examined as the independent variables, whereas the total phenolic content was the response. The developed experimental model was evaluated statistically and found to fit well, considering the lack of fit p-value of 0.184 and coefficient of determination as 0.9731 at the 95% confidence level. The extract prepared by optimized conditions as 56.1 minutes of extraction time and 49.5 mL of solvent volume containing 61.4% ethanol had a total phenolic content of 53.5 ± 1.9 μg of pyrocatechol equivalent/mg extract. The phenolic compounds of the prepared extract were quantified by liquid chromatography-tandem mass spectrometry. Rosmarinic acid was found to be the major component with a concentration of 22.702 mg/g extract.

This study aimed to improve the thrombolytic activity of Astragalus membranaceus using magnetic cellulose-immobilized Bacillus natto fermentation. The fermentation parameters: time, temperature, pH, inoculum amount and solid-liquid ratio were screened by one-way experiments, and Plackett-Burman experiments were performed to determine the fermentation time, temperature, and inoculum amount as the key influencing factors, and the steepest-climbing experiments were performed to optimize the parameters, and then Box-Behnken design (BBD) experiments were conducted to determine the optimal conditions, which significantly increased the thrombolytic efficiency of Astragalus membranaceus immobilized natto fermentation to 311.156 IU/mg and exhibited superior antioxidant activity at 52.23 h of fermentation, an inoculum volume of 1.54 g/g, and a liquid-solid ratio of 30.61 mL/g. In addition, introducing deep eutectic solvent (DES) further enhanced the damage effect. The optimal type and concentration of DES were determined by screening. The magnetic cellulose system exhibited excellent thrombolytic activity and reusability compared to the calcium alginate immobilized system. This study provides a new strategy for immobilizing Bacillus natto provides a scientific basis for developing novel and efficient thrombolytic agents and highlights the potential of magnetic cellulose systems for biocatalysis and biomedical applications.

This study investigates the underlying extraction kinetics and thermodynamic principles driving the process, building on earlier research that enhanced thermosonication (TS) settings to boost the bioactive components of Sohshang (Elaeagnus latifolia) fruit juice. Responses were assessed over a temperature range of 30 °C to 50 °C after the ideal thermosonicated sohshang fruit juice (TSSJ) processing parameters (50% amplitude, 40 °C, and 60 minutes) were determined using the integrated ANN-GA model. The study uses kinetic modeling to determine the best mathematical fit by analyzing the release patterns of functional components like ascorbic acid (AA), total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (AOA). With the highest R² (0.99) and lowest χ² (0.64) values for each of the five responses of various kinetic modeling, the pseudo second-order model was determined to be the best appropriate model. To comprehend the energy requirements and viability of thermosonication-assisted extraction, important thermodynamic parameters were also measured, such as activation energy (Ea: 23.29 to 29.23), enthalpy (ΔH: 15.91 to 58.05 kJ/mol), entropy (ΔS: 42.87 to 112.24 J/mol K), and Gibbs free energy (ΔG: -12.97 to -40.00 kJ/mol).

Chikungunya virus (CHIKV) is a mosquito-borne pathogen responsible for recurring outbreaks, highlighting the need for rapid and accurate diagnostic tools. The E2 glycoprotein of CHIKV is a promising target for antibody-based detection. This study aims to determine the optimal expression conditions of recombinant single-chain variable fragment (scFv) fused with biotin acceptor domain (BAD) specific to the CHIKV E2 glycoprotein in Escherichia coli Origami B (DE3). The optimization was performed using the Box-Behnken design of response surface methodology (RSM), with the IPTG inducer concentration, induction time, and induction temperature as the independent variables. The optimal conditions were identified as 0.2 mM IPTG, 2 hours induction at 37 °C, resulting in a total protein concentration of 0.658 mg/mL. The soluble fraction of scFv-BAD was successfully purified using Ni²⁺-NTA affinity chromatography, with a purity of 91.11%. ELISA confirmed that the recombinant scFv-BAD was biotinylated and retained its ability to bind the CHIKV E2 antigen. The optimized scFv-BAD construct demonstrates potential for use in various immunoassay platforms, including rapid diagnostic tests for CHIKV detection.

Black glutinous rice bran (BGRB) serves as a plentiful natural pigment source. However, limited research has been conducted on the extraction, purification, and characterization of the anthocyanins present in BGRB. This work aims to provide an eco-friendly process for industrial anthocyanin extraction and purification. Following green chemistry principles, safe solvents and recyclable purification materials were used in the experiment. And waste production and energy consumption were limited. Optimal extraction conditions: ethanol-water ratio 40:60 (v/v, pH 2.5), solvent-feed ratio 80:1 (mL/g), 50 °C, and 40 min yielded 19.79 ± 0.14 mg/g anthocyanin, and 32 anthocyanins were identified in the BGRB anthocyanin extract. Optimal purification conditions: employing a D101/AB-8 mixed resin (7:3 w/w), the volume, pH value, and flow rate of BGRB anthocyanin extract were 1.5 Bed Volumes (BV), pH 3.0, and 0.5 BV/hr, respectively; desorption was performed successively with 40:60 (v/v, pH 2.5) ethanol-water of 6 BV, 0.5 BV/hr. Purification achieved 65.97% anthocyanin recovery. After purification, total anthocyanins (67.70 ± 5.43 mg/g to 171.27 ± 7.99 mg/g) and color value (33.48 ± 2.91 to 84.58 ± 1.41) were both 2.5 times higher than in the extract. The metabolite expression of purified anthocyanins showed 4.2 times increase by liquid chromatography-mass spectrometry (LC-MS).

Microbial infestation related food loss poses a major threat to the global food sector. Both bacterial and fungal infestations play a crucial role in the food deterioration and various health issues. This has led to the increased demand for the development of active packaging materials. In the current study, selected essential oils were subjected to MIC, MBC and MFC analysis against both bacterial and fungal agents. Further to this, PVA based bionanocomposites were developed by incorporating the selected essential oils along with ZnONPs. By the FTIR analysis, the interactions among individual components of the developed thin films could be confirmed. Interestingly, the incorporation of nanoparticles was found to have modulatory effect on the release of essential oil components from the films as evidenced by the GC-MS analysis. Further to this, the films were also demonstrated to have enhanced mechanical properties and low moisture content which favor its application as promising packaging material. The incorporation of ZnONPs was also observed to positively modulate the antibacterial and antifungal activity of the films without compromising its microbial barrier efficacy. The findings of the current study thus indicate the potential of the developed bionanocomposite films as antimicrobial packaging systems.

Olive pomace, a by-product of olive oil production, remains underexplored despite its potential environmental and economic benefits. This study sequentially extracted three polysaccharides (OERC, OERH, and OERA) from olive pomace using water at room temperature, hot water (80 °C), and 2% Na₂CO₃ solution (60 °C). Characterization through UV-Vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, high-performance liquid chromatography, and Congo red experiment revealed that these polysaccharides are heteropolysaccharides primarily composed of glucose, mannose, rhamnose, and galactose, each with distinct molar ratios. The polysaccharides exhibited significant antioxidant activity by scavenging hydroxyl, DPPH, and superoxide radicals, with OERC showing the highest potency. They also repaired H₂O₂-induced oxidative damage in HepG2 cells, with OERC at 400 μg/mL and OERH/OERA at 200 μg/mL displaying optimal efficacy. Additionally, these polysaccharides effectively inhibited α-glucosidase activity, enhanced glucose consumption, and increased glycogen content in insulin-resistant models, thereby exerting hypoglycemic effects. Furthermore, they promoted proliferation, phagocytosis, and nitric oxide release in RAW264.7 macrophages, demonstrating immunomodulatory effects. These results indicate that sequential extraction under varying conditions is an effective method for preparing polysaccharides. The three polysaccharides isolated in this study show great potential for development as functional products with antioxidant, hypoglycemic, and immunomodulatory applications.