Recovery of Y(III) from wastewater by Pseudomonas psychrotolerans isolated from a mine soil.

While microbial technologies, which are considered to be environmentally friendly, have great potential for the recovery of rare earth elements (REEs) from mining wastewater, their applications have been restricted due to a lack of efficient biosorbents. In this study, a strain of Pseudomonas psychrotolerans isolated from yttrium-enriched mine soil was used to recover yttrium (Y(III)) from rare-earth mining wastewater. At an initial Y(III) dose of 50 mg L-1, the amount of Y(III) adsorbed by P. psychrotolerans reached 99.9 % after 24 h. Various characterization techniques revealed that P. psychrotolerans adsorbed Y(III) mainly through complexation of oxygen-containing functional groups and electrostatic interactions. A high level of adsorption efficiency (>99.9 %) was maintained after five consecutive adsorption/desorption cycles, indicating that P. psychrotolerans was highly reusable. While the efficiency of adsorbing Y(III) by P. psychrotolerans decreased (34.4 %) in actual rare earth mining wastewater, selectivity toward other REEs (≤ 18.4 %) was still observed. Consequently, this study provides a promising green, environmentally friendly and sustainable microbial approach for the selective recovery of REEs from rare earth wastewater.

Green rGO/FeNPs nanocomposites activated peroxydisulfate for the removal of mixed 17ß-estradiol and estriol.

Reduced graphene oxide/iron nanoparticles (rGO/FeNPs) synthesized by the chemical method have been used in Fenton oxidation of organic contaminants, yet little is known about biosynthesized rGO/FeNPs using green tea extract (GT) as how to activate persulfate in sulfate radical-based advanced oxidation processes. In this study, rGO/FeNPs were used to activate peroxydisulfate (PDS) for 17ß-estradiol (ßE2) and estriol (E3) removal. The rGO/FeNPs-PDS system removed 83.6% of ßE2 and 62.5% of E3 within 240 min, which was confirmed by a combination of adsorption and degradation via both radical and non-radical pathways. Four main reactive species in ßE2 and E3 degradation were observed, i.e., hydroxyl radical (·OH), sulfate radical (SO4·-), singlet oxygen (1O2) and electron transfer, with the respective contributions of ·OH (32.9 and 34.7%), SO4·- (16.1 and 19.7%), 1O2 (12.2 and 14.1%) and electron transfer (8.0 and 7.2%). Analysis of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Electron Paramagnetic Resonance (EPR) and electrochemical measurements all indicated that beside the well-known role of Fe, CO from rGO through the generation of ·OH, SO4·-, 1O2 and electron transfer, as well as GT through electron transfer also participated in the activation of PDS. Finally, the degradation pathways of ßE2/E3 were proposed. Overall, this study provides a new insight into the biosynthesis of rGO/FeNPs to activate PDS for the oxidation of mixed emerging contaminants.

Optimizing the method for removing MSNs templates using an ionic liquid ([C4mim]Cl).

The key step in preparing mesoporous silica is to remove the organic template agent, and the most common method used to achieve this goal is high-temperature calcination. However, this method has many disadvantages, one of which is that it reduces the silanol density on the surface of mesoporous silica, which affects its subsequent modification. Ionic liquids (ILs) are often used as extractants. In this work, the 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) IL is considered, and the effects of its concentration, reaction temperature, and reaction time as well as HCl concentration on the extraction rate and silanol density were investigated using an IL extraction template agent (cetyl trimethyl ammonium bromide (CTAB)). The results show that an IL concentration of 10%, a reaction temperature of 120 °C, a reaction time of 12 h, and an HCl concentration of 1% are the best reaction parameters; with these parameters, the extraction rate and the silanol density were found to be 93.19% and 2.23%, respectively. The silanol density of mesoporous silica treated by calcination is only 0.81%. A higher silanol density provides more reaction sites, so that the modified mesoporous silica treated with the IL can be loaded with more Zn ions.

Exploring biomarkers associated with severity of knee osteoarthritis in Southern China using widely targeted metabolomics.

BACKGROUND: Metabolomics is a tool to study the pathogenesis of diseases and their associated metabolites, but there are still insufficient metabolomic studies on severe knee osteoarthritis.To investigate the differences in serum metabolites between healthy populations and knee osteoarthritis (KOA) patients in Southern China using widely targeted metabolomics, and to explore biomarkers and their metabolic pathways that could be associated with the severity of KOA. METHODS: There were 10 healthy individuals in the control group and 32 patients with KOA. According to the Kellgren-Lawrence (KL) grading system, KOA was further divided into mild (n = 13, KL grade 1 and 2) and severe (n = 19, KL grade 3 and 4). Serum samples from all participants were collected and analyzed metabolomics based on ultra-performance liquid chromatography/electrospray ionization/tandem mass spectrometry. We screened for differential metabolites between patients and controls, and between mild and severe KOA. We explored the metabolic pathways involved in differential metabolism using the Kyoto Encyclopedia of Genes and Genomes database. RESULTS: Sixty-one metabolites were differentially expressed in the sera of the patient group compared with the control group (45 upregulated and 16 downregulated). Analysis of the mild and severe KOA groups showed a total of 12 differential metabolites. Receiver operating characteristic curve analysis showed N-alpha-acetyl-L-asparagine was a good predictor of advanced osteoarthritis(OA).Differential metabolites are enriched in multiple pathways such as arachidonic acid metabolism. CONCLUSION: Widely targeted metabolomics found that upregulation of the amino acid metabolite N-α-acetyl-L-asparagine was significantly associated with severe KOA and could be a biomarker for predicting severity of KOA. Arachidonic acid metabolism may play an important role in patients with severe KOA.

Gallic Acid Treats Hypertrophic Scar in Rabbit Ears via the TGF-ß/Smad and TRPC3 Signaling Pathways.

Hypertrophic scars (HSs) develop due to excessive collagen deposition and abnormal fibroblast proliferation during wound healing, significantly impacting patient quality of life. Three dosages of GA ointments were administered to rabbit ear HS models to investigate the potential efficacy and mechanism of gallic acid (GA) on HS. Daily application of ointment was performed on the matrix group, the GA ointment groups, and the silicone gel group for 28 days. (No drug treatment was performed on the skin and model groups as a blank group and vehicle group, and silicone gel ointment was topically administered to the silicone gel group as a positive control group.) Scar specimens were collected for histopathology analysis, RNA sequencing analysis, real-time quantitative polymerase chain reaction, and Western blot analysis at the first, second, and fourth weeks after the treatment. Low-dose and medium-dose GA effectively suppressed HS formation and markedly decreased fibroblast infiltration levels and scar thickness. Moreover, decreased expression of TRPC3 mRNA and TGF-ß1, p-Smad2/3, and Smad2/3 protein was observed in the low- and medium-dose GA groups and the silicone gel group. This study provides evidence for the efficacy of GA in treating HS and sheds light on its potential underlying pharmacological mechanisms.

Bionanocomposite based on immobilization of Burkholderia cepacian on GO/MOF and its removal of malachite green from river water.

Bio-nanocomposites have attracted increasing research attention because they are able to integrate bio- and nano-related functions, and subsequently demonstrate potentially beneficial environmental applications. Here, a functional bionanomaterial based on Burkholderia cepacian (FZ) immobilized on GO/ZIF-8 was developed and used to remove malachite green (MG), with functions based on both biodegradation and adsorption. XRD and FTIR results showed that in situ production of GO/ZIF-8 by combining Zn2+ in ZIF-8 with the carboxyl group on the GO surface, led to FZ immobilized in GO/ZIF-8 through covalent bonding. Zeta analysis showed that the surface of FZ and GO/ZIF-8 had different charges under pH = 9.12, suggesting immobilization also occurred via electrostatic action. BET results confirmed that the specific surface area of GO/ZIF-8 was much larger than that of GO and ZIF-8, but the reduced specific surface area of FZ@GO/ZIF-8 could be due to FZ loading on its surface. The efficiency of FZ@GO/ZIF-8 in the removal of MG reached 99% and furthermore retained good stability after five cycles. The efficiency in removing multiple ions in river water reached more than 80%, which is evidence strongly suggesting that FZ@GO/ZIF-8 is an environmental bionanomaterial with effective application potential.

Magnetic Fe3O4@ZIF-8 nanoparticles as a drug release vehicle: pH-sensitive release of norfloxacin and its antibacterial activity.

Metal-organic frameworks (MOFs) have a high specific surface area and inherent biodegradability due to their unique structure and composition. As well, owing to the properties of nanomaterials and especially their magnetic features, Fe3O4 nanoparticles and MOFs composite materials have great potential in the design and application of drug release. The present work: firstly, investigated norfloxacin loading in magnetic metal organic framework (Fe3O4@ZIF-8); and secondly, studied the release of norfloxacin and its antibacterial activity. Results showed the release efficiencies reached 97 % at 310 K after 84 h (pH 7.4). Drug release behavior was tested at various pH levels and it was found that Fe3O4@ZIF-8 has pH-sensitive properties. Furthermore, the release model calculation illustrated that the release process fitted well to the Bhaskar model. The magnetic properties of Fe3O4@ZIF-8 confirmed that the composite has potential application for a targeted drug delivery system. The mechanism of pH-responsive norfloxacin release was combined with diffusion, ion exchange and electrostatic repulsion. Furthermore, the antibacterial activities of Fe3O4@ZIF-8 and NOR-Fe3O4@ZIF-8 were tested against Escherichia coli. Results showed that Fe3O4@ZIF-8 had good biocompatibility while NOR-Fe3O4@ZIF-8 can deter or inhibit the actions of microorganisms.

Chinese Medicine as Supporting Therapy for Psoriasis: Past, Present, and Future.

Psoriasis is a chronic skin disease and an important health concern. Western medicine and therapies are the main treatment strategies for psoriasis vulgaris (PV); however, the overall prognosis of patients with PV is still poor. Therefore, PV prevention is especially crucial. Chinese medicine (CM) has a long history of treating psoriasis, and it has unique wisdom in different cognitive angles and treatment modes from modern medicine. In this review, we first summarized the herbs and ancient CM formulas that have therapeutic effects on PV. Second, the research status and obstacles to the current development of CM in modern medicine were reviewed. Finally, the future of CM in the context of precision medicine and integrated medicine was discussed. After a detailed reading of the abundant literature, we believe that CM, through thousands of years of continuous development and clinical practice, has achieved high effectiveness and safety for PV treatment, despite its surrounding controversy. Moreover, precise analyses and systematic research methods have provided new approaches for the modernization of CM in the future. The treatment of PV with CM is worth popularizing, and we hope it can benefit more patients.

Multi-responsive and programmable actuators made with nacre-inspired graphene oxide-bacterial cellulose film.

In recent years, graphene oxide (GO)-based multi-responsive actuators have attracted great interest due to their board application in soft robots, artificial muscles, and intelligent mechanics. However, most GO-based actuators suffer from low mechanical strength. Inspired by the natural nacre, a graphene oxide-bacterial cellulose (GO-BC) film with a "brick and mortar" structure is constructed. Compared with the pure GO film, the tensile strength of the GO-BC film is increased by about 2 times. Benefiting from the rich oxygen-containing functional groups of GO sheets and BC nanofibers, the cracked GO-BC films can be pasted together with the help of water, which can be used to construct GO-BC films with multi-dimensional complex structures. Subsequently, a GO-BC/polymer actuator capable of responding to various stimuli is successfully developed through a complementary strategy of "active layer and inert layer". Further, based on the water-assisted pasting properties of GO-BC films, a series of GO-BC/polymer actuators with 3D complex deformations can be fabricated by pasting together two or more GO-BC/polymer actuators. Finally, the potential applications of multi-response GO-BC/polymer actuators in flexible robots, artificial muscles, and smart devices are demonstrated through a series of applications such as bionic sunflowers, octopus-inspired soft tentacles, and smart curtains.

Separation and Concentration of Nitrogen and Phosphorus in a Bipolar Membrane Electrodialysis System.

Struvite crystallization is a successful technique for simultaneously recovering PO43- and NH4+ from wastewater. However, recovering PO43- and NH4+ from low-concentration solutions is challenging. In this study, PO43-, NH4+, and NO3- were separated and concentrated from wastewater using bipolar membrane electrodialysis, PO43- and NH4+ can then be recovered as struvite. The separation and concentration of PO43- and NH4+ are clearly impacted by current density, according to experimental findings. The extent of separation and migration rate increased with increasing current density. The chemical oxygen demand of the feedwater has no discernible impact on the separation and recovery of ions. The migration of PO43-, NH4+, and NO3- fits zero-order migration kinetics. The concentrated concentration of NH4+ and PO43- reached 805 mg/L and 339 mg/L, respectively, which demonstrates that BMED is capable of effectively concentrating and separating PO43- and NH4+. Therefore, BMED can be considered as a pretreatment method for recovering PO43- and NH4+ in the form of struvite from wastewater.

One-stage revision arthroplasty in a patient with ochronotic arthropathy accompanied by joint infection: A case report.

BACKGROUND: Ochronotic arthropathy (OcA) is a rare disease, which is caused by the accumulation of homogentisic acid in the joint. Patients with OcA have obvious joint pain and the disease progresses rapidly, eventually resulting in disability. Arthroplasty is an efficacious treatment in patients with OcA. However, when OcA patients have joint infection, is joint replacement an option? In the present report, we performed total knee arthroplasty in a patient with OcA and knee infection under the guidance of one-stage revision theory. CASE SUMMARY: A 64-year-old male was referred to our hospital due to severe left knee pain with limited mobility for 2 years. On physical examination, the patient was found to have dark brown pigmentation of the sclera and auricle. Laboratory test results showed elevations in C-reactive protein level (65.79 mg/L) and erythrocyte sedimentation rate (90.00 mm/h). The patient underwent debridement of the left knee joint, during which the cartilage surface of the knee joint was found to be black-brown in color. Bacterial culture of synovial fluid revealed Achromobacter xylosoxidans. We then carried out arthroplasty under the guidance of the theory of one-stage revision. After surgery, the patient's left knee joint pain disappeared and function recovered without joint infection. CONCLUSION: OcA accompanied by joint infection is rare. One-stage revision arthroplasty may be a treatment option for this disease.

Synthesis of ferroferric oxide@silicon dioxide/cobalt-based zeolitic imidazole frameworks for the removal of doxorubicin hydrochloride from wastewater.

Due to its low-cost, eco-friendliness and easy mode of separation biosynthesized magnetic ferroferric oxide (Fe3O4) can be successfully used for the removal of organic contaminants from wastewater. However, there are some challenges that to date have limited this compound's practical removal efficiency. Thus, in this study, a cobalt-based zeolitic imidazole frameworks (ZIF-67) coated biosynthesized ferroferric oxide@silicon dioxide (Fe3O4@SiO2) magnetic composite (Fe3O4@SiO2/ZIF-67) was prepared to address these issues and subsequently used to remove doxorubicin hydrochloride (DOX). Characterization results showed that the fabricated composite exhibited significant magnetic properties (16.1 emu·g-1) with a size ranging between 50 and 250 nm. The amount of DOX adsorbed by the composite (90.7 mg·g-1) was much higher than either of the component parts, which were only 35.7 and 82.5 mg·g-1 for Fe3O4@SiO2 and ZIF-67 respectively. This indicated enhanced DOX adsorption by Fe3O4@SiO2/ZIF-67. The DOX adsorption best fit a pseudo-second order kinetic and Langmuir adsorption model. These studies suggested that the DOX adsorption mechanism involved a combination of electrostatic interactions, π-π stacking, hydrogen bonding and pore filling. Regeneration and application studies, exposing Fe3O4@SiO2/ZIF-67 to real water samples, practically demonstrated that Fe3O4@SiO2/ZIF-67 with propensity for magnetic separation and recycle is a promising nanomaterial for DOX removal.

A one step synthesis of hybrid Fe/Ni-rGO using green tea extract for the removal of mixed contaminants.

The use of biomass for the synthesis of value-added products, such as functional nanomaterial for the removal of contaminants, is a challenge. In this study, hybrid bimetallic Fe/Ni nanoparticles and reduced graphene supported bimetallic Fe/Ni nanoparticles (Fe/Ni-rGO) were prepared via a one-step green synthesis using green tea extract, and thereafter evaluated for the simultaneous removal of rifampicin (RIF) and Pb(II) from aqueous solution. The efficiencies of Pb(II) and RIF removal by Fe/Ni-rGO were 87.5 and 96.8%, respectively. The removal performance of the hybrid Fe/Ni-rGO was better than either nFe/Ni, rGO, or Fe-rGO. Detailed characterization and analyses of Fe/Ni-rGO indicated that both Fe and Ni nanoparticles were evenly distributed over the surface of rGO and that aggregation of Fe, Ni nanoparticles, and stacking of rGO in the hybrid were decreased. Furthermore, while LC-TOF-MS analysis showed that RIF was degraded into small-molecule fragments, XPS showed that Pb(II) was not reduced to Pb0. The major conditions impacting removal efficiency, adsorption kinetics, and fit to adsorption isotherm models were examined to better understand the removal mechanism. While the adsorption of both contaminants fit well a pseudo-second-order kinetic model, the adsorption of RIF fit the Freundlich isotherm model best, while the adsorption of Pb(II) fit the Langmuir isotherm model best. Thus, the removal mechanism of both contaminants firstly being chemical adsorbed onto the surface, while nFe/Ni continues to participate in the catalytic reduction of RIF. Moreover, Fe/Ni-rGO could be reused and performed well for wastewater treatment, thus suitable as a practical resource recycling technology.

Green magnetic nanomaterial as antibiotic release vehicle: The release of pefloxacin and ofloxacin.

The increased efflux of fluoroquinolone antibiotics to the environment has become of worldwide concern due to their potential to disturb aquatic ecosystems. How to improve the antibiotic release is a challenge. In this work, magnetic Fe3O4 nanoparticles as a drug release vehicle were prepared using the green synthesis method. It is a simple and environmental friendly technique that employs the plant extract as a reducing and coating agent during the preparation process. Antibiotics ofloxacin and pefloxacin served as the drug model and the drug release behavior was tested at various pH levels. The release efficiency of ofloxacin from Fe3O4 reached 99.6% and for pefloxacin it was 57.0% at 310 K after 120 h (pH 10.5). The scanning electron microscope images show that Fe3O4 particles ranged in size from 10 to 40 nm and magnetism testing indicated that saturation magnetization was 58.7 emu/g. Furthermore, zeta potential, FTIR, UV-VIS, XRD and XPS were used to provide the evidence to support the release mechanism, where was based on the pH control. Our work clearly demonstrated that Fe3O4 nanoparticles were a potential as a targeted drug delivery system.

Modified green synthesis of Fe3O4@SiO2 nanoparticles for pH responsive drug release.

A magnetic field activated drug delivery and pH-sensitive controlled drug release system based on carboxyl-modified green synthesized Fe3O4@SiO2 (Fe3O4@SiO2-Glu) nanoparticles was established. Doxorubicin hydrochloride (DOX), as a drug model, was adsorbed onto the Fe3O4@SiO2-Glu nanoparticles' surface, where the observed drug loading capacity of 34.6 mg/g was attributed to electrostatic interaction between -COO- on the surface of Fe3O4@SiO2-Glu and -NH3+ of DOX. The structure, morphology and physiochemical properties of Fe3O4@SiO2-Glu were characterized via TEM, FTIR, XRD, N2 adsorption/desorption isotherms, and Zeta potential measurements. The green synthesized Fe3O4@SiO2-Glu nanoparticles exhibited multilayer architecture with a BET surface area of 79.9 m2/g and a magnetization saturation of 25.9 emu/g. Drug release experiments indicated that DOX was pH trigger released with 60.8% released within 72 h at pH 3.5. This system has important potential implications for the design of more effective and stable magnetic Fe3O4@SiO2-Glu materials as drug carriers for targeted and controlled drug release.

Adsorption of doxorubicin hydrochloride on glutaric anhydride functionalized Fe3O4@SiO2 magnetic nanoparticles.

Since Fe3O4 nanoparticles synthesized by plant extracts possess good bio-compatibility and superparamagnetic properties, the possibility of these could be used as a carrier in drug delivery. In this work, doxorubicin hydrochloride (DOX), an anti-cancer drug, loaded on glutaric anhydride-functionalized magnetic nanoparticles (Fe3O4@SiO2-Glu) was investigated at varying pH values for effective drug delivery. Various factors affecting the adsorption of DOX onto the Fe3O4@SiO2-Glu were examined, where the adsorption efficiency of DOX reached 92% at a concentration of 20 mg/L employing 10 mg of Fe3O4@SiO2-Glu at 303 K in pH 7.4. However, the adsorption efficiency of DOX was decreased to 18% at acidic pH value down to 3.0, implicating that the drug releasing process was controlled by pH. Adsorption kinetics was fitting to pseudo-second-order and the isothermal adsorption conformed to Freundlich isotherm. The morphology and surface composition of the synthesized Fe3O4@SiO2-Glu were characterized by SEM, TEM, and N2 adsorption/desorption isotherms, revealing that the specific surface area being 62.6 m2/g and the size ranging from ~30 to 50 nm. The zeta potential results indicated that Fe3O4@SiO2-Glu were negatively charged in various pH from 3 to 8.5. Characterizations by FTIR and UV-Vis techniques suggested that the DOX was absorbed and it can be delivered by Fe3O4@SiO2-Glu.

Highly efficient removal of antibiotic rifampicin from aqueous solution using green synthesis of recyclable nano-Fe3O4.

Antibiotics in water and soil are persistent, bioaccumulative and toxic to aquatic organisms and human health. To address it, as one of the new technologies, green synthesized magnetic Fe3O4 nanoparticles by Excoecaria cochinchinensis extract used to remove rifampicin (RIF) was investigated in this study. Results showed the adsorption efficiency of RIF reached 98.4% and the maximum adsorption capacity is 84.8 mg/g when 20 mL of RIF at a concentration of 20 M was adsorbed by 10 mg Fe3O4 at a temperature of 303 K. The morphology of the green Fe3O4 characterized by SEM demonstrated the dimensions ranging from 20 to 30 nm. The N2 adsorption/desorption isotherms revealed that the surface area of Fe3O4 was 111.8 m2/g. In addition, adsorption studies indicated that the kinetics fitted the pseudo second-order and isothermal adsorption conformed to the Langmuir isotherm. Furthermore, due to their magnetic properties, the Fe3O4 nanoparticles were easily separated and reused and the mechanism for removing RIF occurred through adsorption rather than chemical redox reaction. Finally, the reusability of Fe3O4 for adsorption of RIF showed that the removal efficiency decreased to 61.5% after five cycles.

Simultaneous removal of amoxicillin, ampicillin and penicillin by clay supported Fe/Ni bimetallic nanoparticles.

This study examined functional bentonite-supported nanoscale Fe/Ni (B-Fe/Ni) for the simultaneous removal of ß-lactam antibiotics such as amoxicillin (AMX), ampicillin (AMP) and penicillin (PEN). The results show only 94.6% of AMX, 80.6% of AMP and 53.7% of PEN were removed in the mixed antibiotic solution, while 97.5% of AMX, 85.1% of AMP and 74.5% of PEN were removed in individual antibiotic solution. The decreased removal in a mixed antibiotic solution was attributed to competition between antibiotics for: firstly, active sites of iron oxide for the adsorption; and secondly, accepted electrons for the degradation in passivation of the nZVI surface. These were confirmed by various characterization techniques. Kinetics studies of mixed antibiotics using B-Fe/Ni confirmed that adsorption and degradation occurred simultaneously as removing of antibiotics in the presence of particles. Furthermore, the stability and durability of B-Fe/Ni applied to remove ß-lactam antibiotics was demonstrated. Finally, B-Fe/Ni was used to reduce the concentration of mixed antibiotics from pharmaceutical wastewater, which indicated B-Fe/Ni is a promising material for antibiotics wastewater treatment.

Molecular cloning and overexpression of an endo-ß-1,4-xylanase gene from Aspergillus niger in industrial Saccharomyces cerevisiae YS2 strain.

The aim of this study was to endow an industrial strain of Saccharomyces cerevisiae with the ability to overexpress the xylanase by constructing a homology-driven integration vector. The total mRNA from a xylanase-producing strain of Aspergillus niger IME-216 was extracted and used as the template for the production of endo-ß-1,4-xylanase cDNA by reverse transcription. The fusion fragment containing the phosphoglycerate kinase promoter, α-factor signal peptide, xylanase gene encoding the mature peptide, and CYC1 terminator was first generated by overlap extension polymerase chain reaction. Then, the vector pUPX was constructed by inserting the fusion fragment into the S. cerevisiae plasmid pUG6. Then, A 2.2-kb rDNA sequence was further cloned and attached to the SalI-digested pUPX to obtain the integration plasmid pUPXR. The pUPXR was linearized by KpnI, transformed into the industrial strain S. cerevisiae YS2 using the lithium acetate method and integrated into the S. cerevisiae chromosome. The maximum yield of the recombinant xylanase produced by the engineered S. cerevisiae strain YS2_2 was 74.8 U per microliter, which was about 1.5-fold higher than the original 50 U per microliter by Aspergillus niger IME-216 strain under the flask culture at 28 °C for 72 h. The findings of our study can be used for further development of industrial S. cerevisiae strain for producing interested enzymes, or improving the achievement of metabolism, for example, simultaneous fermentation of glucose and xylose to producing bioethanol.

Production of an in vitro-derived deletion mutation of Brevibacillus laterosporus by constructing a homology-driven integration vector.

In this study, a homology-driven integration vector and electroporation system was developed to delete a protease gene in the pathogenic bacterium Brevibacillus laterosporus strain G4. Furthermore, an in vitro protease-deficient mutation was generated by introducing the integration vector with a 445-bp protease BLG4 fragment into B. laterosporus chromosomal target via homologous recombination. The BLG4-deficient mutant showed a significant drop in protease activity as compared to the wild-type G4 strain, but had a slight effect on bacterial growth and sporulation. The results revealed that the developed method can become an important tool for studying the molecular pathogenesis mechanisms of B. laterosporus.