Bioprocess and Biosystems Engineering最新文献

The probiotic fermentation of the bioactive substance gamma-aminobutyric acid (GABA) is an attractive research topic. There is still room for further improvement in reported GABA fermentation methods based on a single substrate (l-glutamic acid or l-monosodium glutamate). Here, we devised a pH auto-buffering strategy to facilitate the fermentation of GABA by Levilactobacillus brevis CD0817. This strategy features a mixture of neutral monosodium l-glutamate plus acidic l-glutamic acid as the substrate. This mixture provides a mild initial pH; moreover, the newly dissolved l-glutamic acid automatically offsets the pH increase caused by substrate decarboxylation, maintaining the acidity essential for GABA fermentation. In this study, a flask trial was first performed to optimize the GABA fermentation parameters of Levilactobacillus brevis CD0817. The optimized parameters were further validated in a 10 L fermenter. The flask trial results revealed that the appropriate fermentation medium was composed of powdery l-glutamic acid (750 g/L), monosodium l-glutamate (34 g/L [0.2 mol/L]), glucose (5 g/L), yeast extract (35 g/L), MnSO₄·H₂O (50 mg/L [0.3 mmol/L]), and Tween 80 (1.0 g/L). The appropriate fermentation temperature was 30 °C. The fermenter trial results revealed that GABA was slowly synthesized from 0–4 h, rapidly synthesized until 32 h, and finally reached 353.1 ± 8.3 g/L at 48 h, with the pH increasing from the initial value of 4.56 to the ultimate value of 6.10. The proposed pH auto-buffering strategy may be popular for other GABA fermentations.

Endophytic fungi, as plant symbionts, produce an elaborate array of enzymes for efficient disintegration of lignocellulosic biomass into constituent monomeric sugars, making them novel source of lignocellulolytic CAZymes with immense potential in future biorefineries. The present study reports lignocellulolytic enzymes production potential of an endophytic halotolerant Penicillium oxalicum strain isolated from Citrus limon, under submerged and solid-state fermentation (SmF & SSF, respectively), in the presence and absence of salt (1 M NaCl). The comparative QTOF-LC/MS-based exoproteome analysis of the culture extracts unveiled differential expression of CAZymes, with the higher abundance of GH6 and GH7 family cellobiohydrolase in the presence of 1 M salt. The strain improvement program, employing cyclic mutagenesis and diploidization, was utilized to develop hyper-cellulase producing mutant strains of P. oxalicum. The enzyme production of the developed strain (POx-M35) was further enhanced through statistical optimization of the culture conditions utilizing glucose mix disaccharides (GMDs) as an inducer. This optimization process resulted in the lignocellulolytic cocktail that contained high titers (U/mL) of endoglucanase (EG) (146.16), cellobiohydrolase (CBHI) (6.99), β-glucosidase (β-G) (26.21), xylanase (336.05) and FPase (2.02 U/mL), which were 5.47-, 5.54-, 8.55-, 4.96-, and 4.39-fold higher when compared to the enzyme titers obtained in wild HP1, respectively. Furthermore, the lignocellulolytic cocktails designed by blending secretome produced by mutant POx-M35 with xylanases (GH10 and GH11) derived from Malbranchea cinnamomea resulted in efficient hydrolysis of unwashed acid pretreated (UWAP) rice straw slurry and mild alkali deacetylated (MAD) rice straw. This study underscores the potential of bioprospecting novel fungus and developing an improved strain for optimized production and constitution of lignocellulolytic cocktails that can be an important determinant in advancing biomass conversion technologies.

Perfusion cell-culture mode has caught industrial interest in the field of biomanufacturing in recent years. Thanks to new technology, perfusion-culture processes can support higher cell densities, higher productivities and longer process times. However, due to the inherent operational complexity and high running costs, the development and design of perfusion-culture processes remain challenging. Here, we present a model-based approach to design optimized perfusion cultures of Chinese Hamster Ovary cells. Initially, four batches of bench-top reactor continuous-perfusion-culture data were used to fit the model parameters. Then, we proposed the model-based process design approach, aiming to quickly find out the “theoretically optimal” operational parameters combinations (perfusion rate and the proportion of feed medium in perfusion medium) which could achieve the target steady-state VCD while minimizing both medium cost and perfusion rate during steady state. Meanwhile, we proposed a model-based dynamic operational parameters-adjustment strategy to address the issue of cell-growth inhibition due to the high osmolality of concentrated perfusion medium. In addition, we employed a dynamic feedback control method to aid this strategy in preventing potential nutrient depletion scenarios. Finally, we test the feasibility of the model-based process design approach in both shake flask semi-perfusion culture (targeted at 5 × 10⁷ cells/ml) and bench-top reactor continuous perfusion culture (targeted at 1.1 × 10⁸ cells/ml). This approach significantly reduces the number of experiments needed for process design and development, thereby accelerating the advancement of perfusion-mode cell-culture processes.

Encapsulating the enzyme in metal-organic frameworks (MOFs) is a convenient method to prepare MOF-enzyme biocomposite. In this study, Candida antarctica lipase B (CAL-B) was chosen to immobilize in Cu-BTC MOF under ultrasound irradiation. CAL-B was immobilized in Cu-BTC under ultrasound at 21 kHz and 11.4 W/cm² and incubation. 98% of CAL-B was immobilized in Cu-BTC with 99 U/mg activity (threefold more active than the free CAL-B). The prepared biocomposite was characterized using FT-IR, XRD, TGA, SEM, EDX, and BET. The thermal and solvent stability of CAL-B@Cu-BTC was investigated. It was found that at a temperature of 55 ℃, CAL-B@Cu-BTC maintains its activity even after 2 h of incubation. Furthermore, in the presence of 20% and 50% concentrations of MeCN, THF, and DMF, CAL-B@Cu-BTC was found to have an activity of over 80%. A prepared biocatalyst was used to synthesize 1,3,4,5-tetrasubstituted pyrazole derivatives (50-75%) in a one-pot vessel, by adding phenyl hydrazine hydrochlorides, benzaldehydes, and dimethyl acetylenedicarboxylate.

As a result of the changes occurring globally in recent years, millions of people are facing challenging and even life-threatening diseases such as cancer and the COVID-19 pandemic, among others. This phenomenon has spurred researchers towards developing and implementing innovative and environmentally friendly scientific methods, merging disciplines with significant technological potential, such as nanotechnology with medicinal plants. Therefore, the focus of this research is to synthesize zinc nanoparticles (ZnO-NPs) and microflowers (ZnO-MFs) using extracts of the medicinal plant I. oculus christi prepared in n-hexane and methanol as new bioreduction and capping agents through a simple and environmentally friendly chemical approach. Optical, thermal, and morphological structural analyses of ZnO-NPs and ZnO-MFs were conducted using Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, Thermogravimetric Analysis (TGA), and Field Emission Scanning Electron Microscopy (FE-SEM). Metabolic profiles of extracts from different plant parts were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) and supported by visualization of contents through Principal Component Analysis (PCA), hierarchical cluster analysis heatmaps, and Pearson correlation graphs. Interestingly, ZnO-NPs and ZnO-MFs exhibited strong antioxidant properties and demonstrated particularly potent antimicrobial activity against Micrococcus luteus NRRL B-4375, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231 strains compared to standard antibiotics. Furthermore, ZnO-NPs and ZnO-MFs showed excellent plasmid DNA-cleavage activity of pBR322 with increasing doses. The photocatalytic performance of the synthesized ZnO-NPs and ZnO-MFs was evaluated for methylene blue (MB), congo red (CR), and safranin-O (SO) dyes, demonstrating remarkable color removal efficiency. Overall, the results provide a promising avenue for the green synthesis of ZnO-NPs and ZnO-MFs using I. oculus-christi L. inflorescence and pappus extracts, potentially revolutionizing biopharmaceutical and catalytic applications in these fields.

Antibiotics are widely used as fungicides because of their antibacterial and bactericidal effects. However, it is necessary to control their dosage. If the amount of antbiotics is too much, it cannot be completely metabolized and absorbed, will pollute the environment, and have a great impact on human health. Many antibiotics usually left in factory or aquaculture wastewater pollute the environment, so it is vital to detect the content of antibiotics in wastewater. This article summarizes several common methods of antibiotic detection and pretreatment steps. The detection methods of antibiotics in wastewater mainly include immunoassay, instrumental analysis method, and sensor. Studies have shown that immunoassay can detect deficient concentrations of antibiotics, but it is affected by external factors leading to errors. The detection speed of the instrumental analysis method is fast, but the repeatability is poor, the price is high, and the operation is complicated. The sensor is a method that is currently increasingly studied, including electrochemical sensors, optical sensors, biosensors, photoelectrochemical sensors, and surface plasmon resonance sensors. It has the advantages of fast detection speed, high accuracy, and strong sensitivity. However, the reproducibility and stability of the sensor are poor. At present, there is no method that can comprehensively integrate the advantages. This paper aims to review the enrichment and detection methods of antibiotics in wastewater from 2020 to the present. It also aims to provide some ideas for future research directions in this field.

Bio-inspired zinc oxide nanoparticles are gaining immense interest due to their safety, low cost, biocompatibility, and broad biological properties. In recent years, much research has been focused on plant-based nanoparticles, mainly for their eco-friendly, facile, and non-toxic character. Hence, the current study emphasized a bottom-up synthesis of zinc oxide nanoparticles (ZnO NPs) from Psidium guajava aqueous leaf extract and evaluation of its biological properties. The structural characteristic features of biosynthesized ZnO NPs were confirmed using various analytical methods, such as UV-Vis spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). The synthesized ZnO NPs exhibited a hydrodynamic shape with an average particle size of 11.6-80.2 nm. A significant antimicrobial efficiency with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 40 and 27 µg/ml for Enterococcus faecalis, followed by 30 and 40 µg/ml for Staphylococcus aureus, 20 and 30 µg/ml for Staphylococcus mutans, 30 µg/ml for Candida albicans was observed by ZnO NPs. Additionally, they showed significant breakdown of biofilms of Streptococcus mutans and Candida albicans indicating their future value in drug-resistance research. Furthermore, an excellent dose-dependent activity of antioxidant property was noticed with an IC₅₀ of 9.89 µg/ml. The antiproliferative potential of the ZnO NPs was indicated by the viability of MDA MB 231 cells, which showed a drastic decrease in response to increased concentrations of biosynthesized ZnO NPs. Thus, the present results open up vistas to explore their pharmaceutical potential for the development of targeted anticancer drugs in the future.

Biosilica (BS) and spongin (SPG) from marine sponges are highlighted for their potential to promote bone regeneration. Moreover, 3D printing is introduced as a technology for producing bone grafts with optimized porous structures, allowing for better cell attachment, proliferation, and differentiation. Thus, this study aimed to characterize the BS and BS/SPG 3D printed scaffolds and to evaluate the biological effects in vitro. The scaffolds were printed using an ink containing 4 wt.% of sodium alginate. The physicochemical characteristics of BS and BS/SPG 3D printed scaffolds were analyzed by SEM, EDS, FTIR, porosity, evaluation of mass loss, and pH measurement. For in vitro analysis, the cellular viability of the MC3T3-E1 cell lineage was assessed using the AlamarBlue^® assay and confocal microscopy, while genotoxicity and mineralization potential were evaluated through the micronucleus assay and Alizarin Red S, respectively. SEM analysis revealed spicules in BS, the fibrillar structure of SPG, and material degradation over the immersion period. FTIR indicated peaks corresponding to silicon oxide in BS samples and carbon oxide and amine in SPG samples. BS-SPG scaffolds exhibited higher porosity, while BS scaffolds displayed greater mass loss. pH measurements indicated a significant decrease induced by BS, which was mitigated by SPG over the experimental periods. In vitro studies demonstrated the biocompatibility and non-cytotoxicity of scaffold extracts. .Also, the scaffolds promoted cellular differentiation. The micronucleus test further confirmed the absence of genotoxicity. These findings suggest that 3D printed BS and BS/SPG scaffolds may possess desirable morphological and physicochemical properties, indicating in vitro biocompatibility.

Biosurfactants (BSFs) are molecules produced by microorganisms from various carbon sources, with applications in bioremediation and petroleum recovery. However, the production cost limits large-scale applications. This study optimized BSFs production by Bacillus velezensis (strain MO13) using residual glycerin as a substrate. The spherical quadratic central composite design (CCD) model was used to standardize carbon source concentration (30 g/L), temperature (34 °C), pH (7.2), stirring (239 rpm), and aeration (0.775 vvm) in a 5-L bioreactor. Maximum BSFs production reached 1527.6 mg/L of surfactins and 176.88 mg/L of iturins, a threefold increase through optimization. Microbial development, substrate consumption, concentration of BSFs, and surface tension were also evaluated on the bioprocess dynamics. Mass spectrometry Q-TOF-MS identified five surfactin and two iturin isoforms produced by B. velezensis MO13. This study demonstrates significant progress on BSF production using industrial waste as a microbial substrate, surpassing reported concentrations in the literature.

Surface enhanced Raman spectroscopy (SERS) by using gold nanoparticles (AuNPs) has gained relevance for the identification of biomolecules and some cancer cells. Searching for greener NPs synthesis alternatives, we evaluated the SERS properties of AuNPs produced by using different filamentous fungi. The AuNPs were synthesized utilizing the supernatant of Botrytis cinerea, Trichoderma atroviride, Trichoderma asperellum, Alternaria sp. and Ganoderma sessile. The AuNPs were characterized by ultraviolet-visible spectroscopy (UV-Vis) to identify its characteristic surface plasmon resonance, which was located at 545 nm (B. cinerea), 550 nm (T. atroviride), 540 nm (T. asperellum), 530 nm (Alternaria sp.), and 525 nm (G. sessile). Morphology, size and crystal structure were characterized through transmission electron microscopy (TEM); colloidal stability was assessed by Z-potential measurements. We found that, under specific incubation conditions, it was possible to obtain AuNPs with spherical and quasi-spherical shapes, which mean size range depends on the fungal species supernatant with 92.9 nm (B. cinerea), 24.7 nm (T. atroviride), 16.4 nm (T. asperellum), 9.5 nm (Alternaria sp.), and 13.6 nm (G. sessile). This, as it can be expected, has an effect on Raman amplification. A micro-Raman spectroscopy system operated at a wavelength of 532 nm was used for the evaluation of the SERS features of the AuNPs. We chose methylene blue as our target molecule since it has been widely used for such a purpose in the literature. Our results show that AuNPs synthesized with the supernatant of T. atroviride, T. asperellum and Alternaria sp. produce the stronger SERS effect, with enhancement factor (EF) of 20.9, 28.8 and 35.46, respectively. These results are promising and could serve as the base line for the development of biosensors through a facile, simple, and low-cost green alternative.