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The remarkable efficacy of COVID-19 vaccines has established mRNA as a highly promising biomedical technology. However, the adequate application of mRNA therapeutics necessitates additional measures to mitigate the inherent immunogenicity, which is predominantly caused by dsRNA. As a byproduct of the in vitro transcription of mRNA, dsRNA was reported to be originated through several distinct mechanisms, including the extension of 3′ loop-back hairpins, the extension of hybridized abortive transcripts, and promoter-independent transcription. The intricate mechanisms involved pose a dilemma as the reduction in dsRNA results in a concomitant decrease in other critical quality attributes of mRNA. Here, we demonstrate that the promoter binding motifs of T7 RNA polymerase directly impact the production of promoter-independent transcription-based dsRNA. Specifically, the G753A mutation significantly reduces the formation of dsRNA byproducts, which can further combine with modified nucleotides to enhance the effectiveness of dsRNA mitigation and with previously reported high-integrity mutation K389A to minimize side effects. Accordingly, the present study reports a cost-effective approach to synthesize high-purity, less immunostimulatory mRNA by using an engineered T7 RNA polymerase mutant. [ABSTRACT FROM AUTHOR]

In this research, silver-loaded biochar (C-Ag) was acquired from a waste fish scale, and nanocellulose (CNF) was prepared from the waste wheat stalk. Then C-Ag was loaded into chitosan-polyvinyl alcohol hydrogel (CTS-PVA) with CNC as a reinforcement agent, and a novel nanocomposite material was acquired, which could be efficiently applied for antibacterial and dye removal. By plate diffusion analysis, the inhibition areas of C-Ag-CTS-PVA-CNF (C/CTS/PVA/CNF) hydrogel against E. coli ATCC25922, S. aureus ATCC6538, and P. aeruginosa ATCC9027 could reach 22.5 mm, 22.0 mm, and 24.0 mm, respectively. It was found that the antibacterial rate was 100% in the water antibacterial experiment for 2 h, and the antibacterial activity was more than 90% within 35 days after preparation, and the antibacterial rate was more than 90% after repeated antibacterial tests for five times. Through swelling, water adsorption, water loss rate, and water content tests, the hydrogel manifested good moisturizing properties and could effectually block the loss of water and improve the stability of the C/CTS/PVA/CNF hydrogel. The pseudo-first-order and pseudo-second-order models were built, and the adsorption capacity of hydrogel to dye was analyzed, and the dye removal was more consistent with the pseudo-first-order kinetic model. The best removal effect for Congo red was 96.3 mg/g. The C/CTS/PVA/CNF hydrogel had a remarkable removal efficacy on Malachite green, Methyl orange, Congo red, and Methylene blue. As a result, the C/CTS/PVA/CNF hydrogels had robust antibacterial properties and reusability. In addition, the present research developed a facile strategy for effectual dyes removal from the aqueous medium. [ABSTRACT FROM AUTHOR]

Microbial contamination remains a global issue threatening human health. In this research, silver nanoparticles (AgNPs) were fabricated using Osmanthus fragrans flower extract as a reducing agent, and biochar derived from carbonizing waste barley distillers' grain shells was used as a support to fabricate silver-loaded carbon (C-AgNP, C-Ag). PVA-CS-C-Ag-St gel was acquired by cross-linking polyvinyl alcohol (PVA), chitosan (CS), and starch (St) with glutaraldehyde (GA). Results from SEM, FTIR, and XRD demonstrated that PVA, CS, St, and C-Ag were successfully incorporated into the gel. The PVA-CS-C-Ag-S gel showcased excellent swelling and water retention properties, which had substantial antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, with inhibition zones of 25.0 mm, 22.5 mm, and 18.0 mm, respectively. Finally, the antimicrobial analysis revealed that PVA-CS-C-Ag-St gel exhibited excellent antimicrobial properties against typical Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Overall, the PVA-CS-C-Ag-St gel holds great promise for food preservation and environmental pollution control. [ABSTRACT FROM AUTHOR]

Simvastatin is a widely used statin medication that is commonly prescribed to lower cholesterol levels and reduce the risk of cardiovascular events. It is marketed under the brand name Zocor and is known for its effectiveness in treating high cholesterol and managing cardiovascular disease. Monacolin J is an important precursor used to synthesize simvastatin and is mainly produced by chemical methods in industry. Here, monacolin J was synthesized through an enzymatic method under optimized reaction conditions. One recombinant Escherichia coli BL21 (DE3) strain containing lovastatin hydrolase (encoded by CDV55_102090) from Aspergillus turcosus was constructed, which effectively transformed 100 g/L of lovastatin to monacolin J within 3.5 h at pH 8.0 and 30 °C, with a conversion rate of >99.8%. Furthermore, the T5010, the temperature at which the residual activity was half of the initial enzymatic activity after 10 min of heat treatment, was >50 °C, indicating the tremendous potential of this bioprocess for synthesizing monacolin J at an industrial scale. [ABSTRACT FROM AUTHOR]

Dandelion extract is a reducing agent, and CuSO4∙5H2O was used as a carrier to create copper nanoparticles (CuNPs). A novel polyvinyl alcohol–chitosan–dandelion–CuNP (PVA/CTS/DAN/CuNP) gel was acquired by cross-linking Polyvinyl alcohol (PVA) and chitosan (CTS) solution. Its structure was analyzed using Fourier transform infrared spectroscopy, Scanning electron microscopy, and X-ray diffraction. The PVA/CTS/DAN/CuNP gels manifested good stability, recycling ability, swelling properties, and biocompatibility. Using the agar diffusion method, the diameters of the inhibition zone of the composite gel against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa could be over 21 mm. In conclusion, the PVA/CTS/DAN/CuNP composite gel had good antibacterial performance, which has a high potential for application in microbial contamination treatment and environmental protection. [ABSTRACT FROM AUTHOR]

Furfural, an important biobased compound, can be synthesized through the chemocatalytic conversion of D-xylose and hemicelluloses from lignocellulose. It has widespread applications in the production of valuable furans, additives, resins, rubbers, synthetic fibers, polymers, plastics, biofuels, and pharmaceuticals. By using barley hulls (BHs) as biobased support, a heterogeneous biochar Sn-NUS-BH catalyst was created to transform corncob into furfural in cyclopentyl methyl ether–H2O. Sn-NUS-BH had a fibrous structure with voids, a large comparative area, and a large pore volume, which resulted in more catalytic active sites. Through the characterization of the physical and chemical properties of Sn-NUS-BH, it was observed that the Sn-NUS-BH had tin dioxide (Lewis acid sites) and a sulfonic acid group (Brønsted acid sites). This chemocatalyst had good thermostability. At 170 °C for 20 min, Sn-NUS-BH (3.6 wt%) was applied to transform 75 g/L of corncob with ZnCl2 (50 mM) to generate furfural (80.5% yield) in cyclopentyl methyl ether–H2O (2:1, v/v). This sustainable catalytic process shows great promise in the transformation of lignocellulose to furfural using biochar-based chemical catalysts. [ABSTRACT FROM AUTHOR]

Objective: Optically active (R)-ethyl 4-chloro-3-hydroxybutyrate ((R)-CHBE) is a useful chiral building block for the synthesis of pharmaceuticals. Recently, there has been great interest in the synthesis of (R)-CHBE via the highly stereoselective bioreduction of ethyl 4-chloro-3-oxobutanoate (COBE) under mild conditions. Methods: A highly efficient bioreduction process for transforming COBE into (R)-CHBE was developed in a biocompatible organic solvent–deep eutectic solvent–water reaction medium. Results: Recombinant Escherichia coli containing carbonyl reductase (CgCR) and glucose dehydrogenase (GDH) was successfully constructed and characterized. In addition, the feasibility of the asymmetric bioreduction of COBE to (R)-CHBE was verified in an organic solvent–deep eutectic solvent–water (ethyl acetate-betaine/lactic acid-water) system. At pH 7.0 and 30 °C, the kinetic constants Km and kcat of COBE were 20.9 mM and 56.1 s−1, respectively. A high (R)-CHBE yield (≥90%) was achieved by catalyzing COBE (1000 mM) in 12 h with E. coli CgCR cells in the presence of Ni2+ (7 mM) and glucose (3.5 mM glucose/mM COBE) in an ethyl acetate-betaine/lactic acid-H2O (50/7/43, v/v/v) system. The effects of organic solvents and DESs on whole-cell permeability were analyzed. Conclusions: An efficient bioreduction system was constructed for biologically transforming COBE to (R)-CHBE via whole-cell biocatalysis, and the established bioprocess has potential application in future. [ABSTRACT FROM AUTHOR]

Microbial contamination has caused various diseases via pathogenic bacteria, endangering people's lives every day. Recently, increasing attention has been paid to the exploration of new and effective antibacterial materials. In this paper, we attempted to synthesize a fish scale charcoal nanosilver antibacterial composite using waste fish scale as a carbon substrate. X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetry-differential scanning calorimetry, and scanning electron microscopy showed that the structure of the nanosilver fish scale material formed and the nanosilver particles formed account for 72.1% of the silver element. Its antibacterial ability against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa was examined using the plate counting method and inhibition zones; the maximum inhibition zone was 32 mm. The antibacterial rate could reach >99.9%, indicating that this prepared material had excellent antibacterial activity. After 20 batches of bacteriostasis, the bacteriostasis rate was more than 90%, indicating that the fish scale/silver composite had sustained antibacterial ability and excellent antibacterial reusability. Finally, potential antibacterial mechanism was proposed. Overall, the fish scale/silver composite has a good application prospect and a wide range of applications in the handling of microbial pollution in the future. [ABSTRACT FROM AUTHOR]

Background: Lignocellulose-derived aldehyde inhibitors seriously blocked the biorefinery of biofuels and biochemicals. To date, the economic production of lignocellulose-based products heavily relied on high productivities of fermenting strains. However, it was expensive and time-consuming for the achievable rational modification to strengthen stress tolerance robustness of aldehyde inhibitors. Here, it aimed to improve aldehyde inhibitors tolerance and cellulosic bioethanol fermentability for the chassis Zymomonas mobilis ZM4 pretreated using energy-efficient and eco-friendly cold plasma. Results: It was found that bioethanol fermentability was weaker in CSH (corn stover hydrolysates) than that in synthetic medium for Z. mobilis, and thus was attributed to the inhibition of the lignocellulose-derived aldehyde inhibitors in CSH. Convincingly, it further confirmed that the mixed aldehydes severely decreased bioethanol accumulation through additional aldehydes supplementary assays in synthetic medium. After assayed under different processing time (10–30 s), discharge power (80–160 W), and working pressure (120–180 Pa) using cold atmosphere plasma (CAP), it achieved the increased bioethanol fermentability for Z. mobilis after pretreated at the optimized parameters (20 s, 140 W and 165 Pa). It showed that cold plasma brought about three mutation sites including ZMO0694 (E220V), ZMO0843 (L471L) and ZMO0843 (P505H) via Genome resequencing-based SNPs (single nucleotide polymorphisms). A serial of differentially expressed genes (DEGs) were further identified as the potential contributors for stress tolerance via RNA-Seq sequencing, including ZMO0253 and ZMO_RS09265 (type I secretion outer membrane protein), ZMO1941 (Type IV secretory pathway protease TraF-like protein), ZMOr003 and ZMOr006 (16S ribosomal RNA), ZMO0375 and ZMO0374 (levansucrase) and ZMO1705 (thioredoxins). It enriched cellular process, followed by metabolic process and single-organism process for biological process. For KEGG analysis, the mutant was also referred to starch and sucrose metabolism, galactose metabolism and two-component system. Finally, but interestingly, it simultaneously achieved the enhanced stress tolerance capacity of aldehyde inhibitors and bioethanol fermentability in CSH for the mutant Z. mobilis. Conclusions: Of several candidate genetic changes, the mutant Z. mobilis treated with cold plasma was conferred upon the facilitated aldehyde inhibitors tolerance and bioethanol production. This work would provide a strain biocatalyst for the efficient production of lignocellulosic biofuels and biochemicals. [ABSTRACT FROM AUTHOR]