Enantioselective Construction of Quaternary Stereocenters via Cooperative Photoredox/Fe/Chiral Primary Amine Triple Catalysis.

The catalytic and enantioselective construction of quaternary (all-carbon substituents) stereocenters poses a formidable challenge in organic synthesis due to the hindrance caused by steric factors. One conceptually viable and potentially versatile approach is the coupling of a C-C bond through an outer-sphere mechanism, accompanied by the realization of enantiocontrol through cooperative catalysis; however, examples of such processes are yet to be identified. Herein, we present such a method for creating different compounds with quaternary stereocenters by photoredox/Fe/chiral primary amine triple catalysis. This approach facilitates the connection of an unactivated alkyl source with a tertiary alkyl moiety, which is also rare. The scalable process exhibits mild conditions, does not necessitate the use of a base, and possesses a good functional-group tolerance. Preliminary investigations into the underlying mechanisms have provided valuable insights into the reaction pathway.

Energy-Transfer-Mediated Photocatalysis by a Bioinspired Organic Perylenephotosensitizer HiBRCP.

Energy transfer plays a special role in photocatalysis by utilizing the potential energy of the excited state through indirect excitation, in which a photosensitizer determines the thermodynamic feasibility of the reaction. Bioinspired by the energy-transfer ability of natural product cercosporin, here we developed a green and highly efficient organic photosensitizer HiBRCP (hexaisobutyryl reduced cercosporin) through structural modification of cercosporin. After structural manipulation, its triplet energy was greatly improved, and then, it could markedly promote the efficient geometrical isomerization of alkenes from the E-isomer to the Z-isomer. Moreover, it was also effective for energy-transfer-mediated organometallic catalysis, which allowed realization of the cross-coupling of aryl bromides and carboxylic acids through efficient energy transfer from HiBRCP to nickel complexes. Thus, the study on the relationship between structural manipulation and their photophysical properties provided guidance for further modification of cercosporin, which could be applied to more meaningful and challenging energy-transfer reactions.

[Experiment on Jianpi Qingre Huoxue Decoction Drug Serum Regulates SW480 Cell Proliferation,Apoptosis,Cycle and the Expression of ß-Catenin by Altering PI3K/Akt Signal Pathway].

Objective: To study Jianpi Qingre Huoxue decoction( JPQRHX) in preventing colon cancer by observing SW480 cells proliferation,apoptosis,cycle and the expression of P-ß-catenin, and to research its mechanism. Methods: SW480 cells were incubated with serum containing blank serum, different concentrations of JPQRHX decocition and PI3 K blocking agent LY294002 for 24 h,respectively. Cell proliferation was detected by MTT assay, cell cycle and apoptosis were detected by flow cytometry. The protein translocation of P-ß-catenin was assayed by immunofluorescent staining. Results: The inhibitory rate and apoptosis rate in JPQRHX decoction group were higher than control group( P < 0. 05),respectively. S phase cells were increased significantly, and G1 phase cells and LY294002 group cells were decreased significantly( P < 0. 05). The P-ß-catenin in JPQRHX decoction groups were mainly expressed in membrane, while the P-ß-catenin in the control group was characterized by deletion in membrane and increased in nucleus. Conclusion: JPQRHX decoction has the ability in curing colon cancer, and the mechanism is associated with altering the expression of P-ß-catenin in the cells nucleus, blocking SW480 cells cycle at G1 phase, inhibiting SW480 cells proliferation, and inducing SW480 cell apoptosis.

Tracking the transformation of extracellular polymeric substances during the ultraviolet/peracetic acid disinfection process: Emphasizing on molecular-level analysis and overlooked mechanisms.

In this study, the transformation mechanisms of extracellular polymeric substances (EPS) during ultraviolet/peracetic acid (UV/PAA) disinfection were elucidated based on multiple molecular-level analyses. After UV/PAA disinfection, the contents of soluble EPS (S-EPS), loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) were reduced by 70.47 %, 57.05 % and 47.46 %, respectively. Fluorescence excitation-emission matrix-parallel factor and Fourier transform ion cyclotron resonance mass spectrometry analyses showed that during UV/PAA disinfection, EPS was transformed from the state characterized by high aromaticity, low saturation and low oxidation to the one with reduced aromaticity, increased saturation and higher oxidation. Specifically, sulfur-containing molecules (CHOS, CHONS, etc.) in EPS were converted into highly saturated and oxidized species (such as CHO), with the aromaticity index (AImod) decreasing by up to 53.84 %. Molecular characteristics analyses further indicated that saturation degree, oxidation state of carbon and molecular weight exhibited the most significant changes in S-EPS, LB-EPS and TB-EPS, respectively. Additionally, mechanistic analysis revealed that oxygen addition reaction was the predominant reaction for S-EPS (+O) and TB-EPS (+3O) (accounting for 31.78 % and 36.47 %, respectively), while the dealkylation was the main reaction for LB-EPS (29.73 %). The results were consistent with functional groups sequential responses analyzed by Fourier transform infrared and two-dimensional correlation spectroscopy, and were further verified by density functional theory calculations. Most reactions were thermodynamically feasible, with reaction sites predominantly located at functional groups such as CO, CO, CN and aromatic rings. Moreover, metabolomics analysis suggested that changes in metabolites in raw secondary effluent during UV/PAA disinfection were strongly correlated with EPS transformation. Our study not only provides a strong basis for understanding EPS transformation during UV/PAA disinfection at molecular-level but also offers valuable insights for the application this promising disinfection process.

Insight into using hydrochar to alleviate ammonia nitrogen inhibition during anaerobic digestion of waste activated sludge: Performance, metagenomic and metabolomic signatures.

In this study, hydrochar (HCR) was used to alleviate high ammonia inhibition to the anaerobic digestion (AD) of waste activated sludge (WAS) and to elucidate the inner microorganism mechanism. After HCR addition, the cumulative methane yield increased by 73.6 % and 35.6 % under ammonia inhibition levels of 3000 and 6000 mg/L, respectively. Metagenomic analysis showed that HCR enriched the diversity of hydrogenotrophic methanotrophs, and the relative abundances of functional microorganisms with electron transfer capabilities (Geobacteraceae bacterium etc.) were 1.5-7.8 times higher than those without HCR addition. Metabolomics analysis implied that metabolites related to fatty acid degradation, such as glutaric acid and hexadecanal, were downregulated (2.9-15.7 %) under ammonia inhibition conditions and that HCR regulates metabolites in the methane metabolic pathway. Moreover, HCR changed the methanogenic pathway from hydrogenotrophic methanogenesis to multiple pathways under ammonia inhibition conditions, especially methanolic and methylotrophic methanogenesis, which facilitated the methane yield. This study provides valuable information for understanding the inner microbial mechanism of HCR addition on alleviating high ammonia inhibition to AD of WAS, and gives basic knowledge for the application of AD of WAS under ammonia inhibition conditions.

Comparison of different sewage sludge pretreatment technologies for improving sludge solubilization and anaerobic digestion efficiency: A comprehensive review.

Anaerobic digestion (AD) of sewage sludge reduces organic solids and produces methane, but the complex nature of sludge, especially the difficulty in solubilization, limits AD efficiency. Pretreatments, by destroying sludge structure and promoting disintegration and hydrolysis, are valuable strategies to enhance AD performance. There is a plethora of reviews on sludge pretreatments, however, quantitative comparisons from multiple perspectives across different pretreatments remain scarce. This review categorized various pretreatments into three groups: Physical (ultrasonic, microwave, thermal hydrolysis, electric decomposition, and high pressure homogenization), chemical (acid, alkali, Fenton, calcium peroxide, and ozone), and biological (microaeration, exogenous bacteria, and exogenous hydrolase) pretreatments. The optimal conditions of various pretreatments and their impacts on enhancing AD efficiency were summarized; the effects of different pretreatments on microbial community in the AD system were comprehensively compared. The quantitative comparison based on dissolution degree of COD (DDCOD) indicted that the sludge solubilization performance is in the order of physical, chemical, and biological pretreatments, although with each below 40 % DDCOD. Biological pretreatment, particularly microaeration and exogenous bacteria, excel in AD enhancement. Pretreatments alter microbial ecology, favoring Firmicutes and Methanosaeta (acetotrophic methanogens) over Proteobacteria and Methanobacterium (hydrogenotrophic methanogens). Most pretreatments have unfavorable energy and economic outcomes, with electric decomposition and microaeration being exceptions. On the basis of the overview of the above pretreatments, a full energy and economy assessment for sewage sludge treatment was suggested. Finally, challenges associated with sludge pretreatments and AD were analyzed, and future research directions were proposed. This review may broaden comprehension of sludge pretreatments and AD, and provide an objective basis for the selection of sludge pretreatment technologies.

A comprehensive investigation to the fate of phosphorus in full-scale wastewater treatment plants using aluminum salts for enhanced phosphorus removal.

This study investigated the fate of phosphorus (P) in 8 full-scale municipal wastewater treatment plants (WWTPs) in Shanghai, China, in which both biological nutrient removal and aluminum-based chemical phosphorus removal were used. The results showed that 83.8-98.9 % P was transferred to the sludge in the 8 WWTPs by both chemical and biological reactions. P speciation analysis indicated that chemical P precipitates accounted for 84.3 % in the activated sludge, of which crystalline AlPO4 and amorphous iron­phosphorus compounds (FePs) were the main components. Sludge with more water-soluble and weakly adsorbed P was generated in the anaerobic-anoxic-oxic (A/A/O) process than in other processes. Among the 8 WWTPs, the one with the largest flow rate and relatively short sludge retention time (SRT) had the best potential to release P from all types of sludge. The recovery potential of P from thickened sludge can be improved by separately thickening the sludge produced in the high-efficiency sedimentation tank or feeding it into the dewatering process directly. Different P removal chemicals and dosing points changed the amount of chemical precipitate formed but had little effect on the composition of P accumulating organisms (PAOs) at the genus level. Although aluminum-based coagulants were applied in the investigated WWTPs, Fe in wastewater had the most positive effect on the proliferation of PAOs. The synthesis of polyphosphate was also related to the metabolism of PAOs as it affected transmembrane inorganic phosphate (Pi) transport and polyhydroxybutyrate (PHB) synthesis. The in-depth understanding of the fate of P is beneficial to improve P recovery efficiency in WWTPs.

Underlying the mechanisms of pathogen inactivation and regrowth in wastewater using peracetic acid-based disinfection processes: A critical review.

Peracetic acid (PAA) disinfection is an emerging wastewater disinfection process. Its advantages include excellent pathogen inactivation performance and little generation of toxic and harmful disinfection byproducts. The objective of this review is to comprehensively analyze the experimental data and scientific information related to PAA-based disinfection processes. Kinetic models and modeling frameworks are discussed to provide effective tools to assess pathogen inactivation efficacy. Then, the efficacy of PAA-based disinfection processes for pathogen inactivation is summarized, and the inactivation mechanisms involved in disinfection and the interactions of PAA with conventional disinfection processes are elaborated. Subsequently, the risk of pathogen regrowth after PAA-based disinfection process is clearly discussed. Finally, to address ecological risks related to PAA-based disinfection, its impact on the spread of antibiotic-resistant bacteria and the transfer of antibiotic resistance genes (ARGs) is also assessed. Among advanced PAA-based disinfection processes, ultraviolet/PAA is promising not only because it has practical application value but also because pathogen regrowth can be inhibited and ARGs transfer risk can be significantly reduced via this process. This review presents valuable and comprehensive information to provide an in-depth understanding of PAA as an alternative wastewater disinfection technology.

Application of artificial intelligence in (waste)water disinfection: Emphasizing the regulation of disinfection by-products formation and residues prediction.

Water/wastewater ((waste)water) disinfection, as a critical process during drinking water or wastewater treatment, can simultaneously inactivate pathogens and remove emerging organic contaminants. Due to fluctuations of (waste)water quantity and quality during the disinfection process, conventional disinfection models cannot handle intricate nonlinear situations and provide immediate responses. Artificial intelligence (AI) techniques, which can capture complex variations and accurately predict/adjust outputs on time, exhibit excellent performance for (waste)water disinfection. In this review, AI application data within the disinfection domain were searched and analyzed using CiteSpace. Then, the application of AI in the (waste)water disinfection process was comprehensively reviewed, and in addition to conventional disinfection processes, novel disinfection processes were also examined. Then, the application of AI in disinfection by-products (DBPs) formation control and disinfection residues prediction was discussed, and unregulated DBPs were also examined. Current studies have suggested that among AI techniques, fuzzy logic-based neuro systems exhibit superior control performance in (waste)water disinfection, while single AI technology is insufficient to support their applications in full-scale (waste)water treatment plants. Thus, attention should be paid to the development of hybrid AI technologies, which can give full play to the characteristics of different AI technologies and achieve a more refined effectiveness. This review provides comprehensive information for an in-depth understanding of AI application in (waste)water disinfection and reducing undesirable risks caused by disinfection processes.

Selective synthesis of rebaudioside M2 through structure-guided engineering of glycosyltransferase UGT94D1.

Rebaudioside M2 (Reb M2), a novel steviol glycoside derivative, has limited industrial applications due to its low synthetic yield and selectivity. Herein, we identify UGT94D1 as a selective glycosyltransferase for rebaudioside D (Reb D), leading to the production of a mono ß-1,6-glycosylated derivative, Reb M2. A variant UGT94D1-F119I/D188P was developed through protein engineering. This mutant exhibited a 6.33-fold improvement in catalytic efficiency, and produced Reb M2 with 92% yield. Moreover, molecular dynamics simulations demonstrated that UGT94D1-F119I/D188P exhibited a shorter distance between the nucleophilic oxygen (OH6) of the substrate Reb D and uridine diphosphate glucose, along with an increased Ophosphate-C1-Oacceptor angle, thus improving the catalytic activity of the enzyme. Therefore, this study provides an efficient method for the selective synthesis of Reb M2 and paves the way for its applications in various fields.

Ni-catalyzed enantioconvergent deoxygenative reductive cross-coupling of unactivated alkyl alcohols and aryl bromides.

Transition metal-catalyzed enantioconvergent cross-coupling of an alkyl precursor presents a promising method for producing enantioenriched C(sp3) molecules. Because alkyl alcohol is a ubiquitous and abundant family of feedstock in nature, the direct reductive coupling of alkyl alcohol and aryl halide enables efficient access to valuable compounds. Although several strategies have been developed to overcome the high bond dissociation energy of the C - O bond, the asymmetric pattern remains unknown. In this report, we describe the realization of an enantioconvergent deoxygenative reductive cross-coupling of unactivated alkyl alcohol (ß-hydroxy ketone) and aryl bromide in the presence of an NHC activating agent. The approach can accommodate substituents of various sizes and functional groups, and its synthetic potency is demonstrated through a gram scale reaction and derivatizations into other compound families. Finally, we apply our convergent method to the efficient asymmetric synthesis of four ß-aryl ketones that are natural products or bioactive compounds.

Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum.

BACKGROUND: Colorectal polyps, which are characterized by a high recurrence rate, represent preneoplastic conditions of the intestine. Due to unclear mechanisms of pathogenesis, first-line therapies for non-hereditary recurrent colorectal polyps are limited to endoscopic resection. Although recent studies suggest a mechanistic link between intestinal dysbiosis and polyps, the exact compositions and roles of bacteria in the mucosa around the lesions, rather than feces, remain unsettled. AIM: To clarify the composition and diversity of bacteria in the mucosa surrounding or 10 cm distal to recurrent intestinal polyps. METHODS: Mucosal samples were collected from four patients consistently with adenomatous polyps (Ade), seven consistently with non-Ade (Pol), ten with current Pol but previous Ade, and six healthy individuals, and bacterial patterns were evaluated by 16S rDNA sequencing. Linear discriminant analysis and Student's t-tests were used to identify the genus-level bacteria differences between groups with different colorectal polyp phenotypes. Pearson's correlation coefficients were used to evaluate the correlation between intestinal bacteria at the genus level and clinical indicators. RESULTS: The results confirmed a decreased level of probiotics and an enrichment of pathogenic bacteria in patients with all types of polyps compared to healthy individuals. These changes were not restricted to the mucosa within 0.5 cm adjacent to the polyps, but also existed in histologically normal tissue 10 cm distal from the lesions. Significant differences in bacterial diversity were observed in the mucosa from individuals with normal conditions, Pol, and Ade. Increased abundance of Gram-negative bacteria, including Klebsiella, Plesiomonas, and Cronobacter, was observed in Pol group and Ade group, suggesting that resistance to antibiotics may be one risk factor for bacterium-related harmful environment. Meanwhile, age and gender were linked to bacteria changes, indicating the potential involvement of sex hormones. CONCLUSION: These preliminary results support intestinal dysbiosis as an important risk factor for recurrent polyps, especially adenoma. Targeting specific pathogenic bacteria may attenuate the recurrence of polyps.

Highly efficient degradation of ofloxacin and diclofenac by composite photocatalyst aloe-emodin/PMMA.

Photocatalysis is one of the most effective methods to remove pollutants from water. Photocatalyst is the core of photocatalysis. The composite photocatalyst combines the photosensitizer with the support and uses the photosensitivity of the photosensitizer and the stability and adsorption of the support to achieve efficient and rapid degradation of pharmaceuticals in water. In this study, natural aloe-emodin with π-conjugated structure was used as photosensitizer to react with macroporous resin polymethylmethacrylate (PMMA) under mild conditions to prepare composite photocatalysts AE/PMMAs. The photocatalyst underwent photogenerated electron migration under visible light to form •O2- and holes with high oxidation activity, which could realize efficient photocatalytic degradation of ofloxacin and diclofenac sodium and showed excellent stability, recyclability and industrial feasibility. This research has developed an efficient method of composite photocatalyst and realized the application of a natural photosensitizer in pharmaceutical degradations.

A novel approach to enhance methane production during anaerobic digestion of waste activated sludge by combined addition of trypsin, nano-zero-valent iron and activated carbon.

A novel approach with a combination of trypsin, nano-zero-valent iron (NZVI) and activated carbon (AC) was conducted to promote the methane production of waste activated sludge (WAS) during the anaerobic digestion (AD) processes. Results showed that the combined addition of trypsin-NZVI-AC exhibited the synergistic effect during different AD stages. Trypsin mainly facilitated the hydrolysis process and the acetic acid conversion, while NZVI-AC enhanced the substrate metabolism and the electronic transfer to subsequently produce methane. A dose of 1000 mg/L trypsin was optimal to maximize this synergistic effect. Metagenomic analysis showed that trypsin-NZVI-AC addition effectively improved the relative abundance of acetyl-CoA carboxylase, and then strengthened both acetoclastic methanogenesis (M00357) and hydrogenotrophic methanogenesis (M00567). Hydrogenotrophic methanogens such as Methanobacterium, Methanoculleus, and Methanosarcina were greatly enriched with trypsin-NZVI-AC compared with trypsin or NZVI-AC addition. Moreover, electroactive bacteria G. sulfurreducens and G. metallireducens were also enriched by this method to conduct direct interspecies electron transfer among methanogens, leading to the better improvement of methane production. These findings supply a promising way to optimize the enzyme pretreatment technology and elevate the methanogenic efficiency of WAS.

Co-digestion of sulfur-rich vegetable waste with waste activated sludge enhanced phosphorus release and hydrogenotrophic methanogenesis.

Anaerobic co-digestion of sulfur-rich vegetable waste (SVW) with waste activated sludge (WAS) and the underlying mechanisms associated with methane production and phosphorus (P) release were investigated. Four types of SVW (Chinese cabbage, cabbage, rapeseed cake, and garlic) were utilized for co-digestion with WAS, and the methane yield increased by 7.3%-35.3%; in the meantime, the P release amount from WAS was enhanced by 9.8%-24.9%. The organic carbon in SVW promoted methane production, while organic sulfur and the formation of FeS facilitated P release. Among the four types of SVW, rapeseed cake was identified as the most suitable co-digestion substrate for enhancing both methane production and P release due to its balanced nutrients and relatively high sulfur content. Syntrophic bacteria working with hydrogenotrophic methanogens, iron-reducing bacteria, sulfate-reducing bacteria, and hydrogenotrophic methanogens were enriched. Metabolic pathways related to sulfate reduction and methanogenesis were facilitated, especially hydrogenotrophic methanogenesis. Enzymes involved in hydrogenotrophic methanogenesis were promoted by 76.05%-407.98% with the addition of Chinese cabbage, cabbage, or rapeseed cake. This study provides an eco-friendly technology for promoting P resource and energy recovery from WAS and an in-depth understanding of the corresponding microbial mechanisms.

Evaluating effects of biochar on anaerobic digestion of dewatered waste activated sludge: Digester performance, microbial co-metabolism and underlying mechanism.

Biochar has been proven to be capable of improving the performance of anaerobic digestion (AD). However, the effect of biochar on microbial communities remains ambiguous. In this study, the influence of pH was excluded in a semi-continuous anaerobic digestor for the treatment of dewatered waste activated sludge (WAS) to determine the effect of biochar on microbes. Compared with the control group, the average methane production increased by 24.5% and 23.2% at the organic loading rates (OLRs) of 1.56 and 3.00 gTS/L/d, respectively, in the presence of biochar. This study innovatively found biochar accelerated the enrichment of Methanofastidiosaceae, which competed with Methanobacteriaceae for H2, and its abundance increased from 0.99% at the OLR of 1.56 g TS/L/d to 16.57% and 38.11% at the OLR of 3.00 and 5.60 gTS/L/d, respectively. The efficient metabolic network of f__norank_o__Aminicenantales, syntrophic bacteria, Methanofastidiosaceae and Methanosaetaceae promoted the conversion of WAS to CH4 in the biochar group. In addition, metagenome analysis revealed that biochar optimized the metabolites related to energy conservation and electron transfer, particularly for hydrogenase (frhABG, mbhLHK and hndA-D), confirming that biochar changed the way H2 was involved in methanogenesis. These findings provide novel insights into the direct effect of biochar on microbial evolution and facilitate the reduction of WAS to achieve higher economic benefits in biogas production.

Speciation analysis and formation mechanism of iron-phosphorus compounds during chemical phosphorus removal process.

Iron (Fe) salt was applied extensively to remove phosphorus (P) in wastewater treatment plants (WWTPs). Exploring the formation mechanism of iron-phosphorus compounds (FePs) during the chemical P removal (CPR) process is beneficial to P recovery. In this study, the performance of P removal, FePs speciation analysis and the kinetics of P removal under different conditions (pH, Fe/P molar ratio (Fe/Pmol), type of Fe salt, dissolved organic matters) were comprehensively investigated. More than 95% of P was removed under the optimal conditions with pH = 4.7, Fe/Pmol = 2, FeCl3 or polymeric ferric sulfate (PFS) as the coagulant. The FePs formation mechanism was considerably influenced by reaction conditions. Iron-phosphate compounds were the dominant FePs species (>76%) at pH < 6.2, while more iron oxides were formed at pH ≥ 6.2 with decreased P removal efficiency. When the initial Fe/Pmol was 2, iron-phosphate compound was the only product that was formed by the reaction between PO43- and Fe(III) or Fe(II) ions directly. More iron oxides were generated when the initial Fe/Pmol was 1 or 3. At Fe/Pmol = 1, the Fe(III) was hydrolyzed to form iron oxides and trapped PO43-, while at Fe/Pmol = 3, iron-phosphate compounds were produced firstly and the remaining Fe(III) was hydrolyzed to form iron oxides. The pseudo-second-order kinetic model simulated the chemical P removal process well. The reaction rate of P with Fe(II) was slower than that with Fe(III), but complete removal was still achieved when the reaction time was more than 30 min. Poly-Fe salt exhibited a fast P removal rate, while the removal efficiency depended on its iron content. Organic matters in wastewater with large molecular weight and multiple functional groups (such as humic acids) inhibited P removal rate but hardly affect the removal amount. This study provides an insight into CPR by Fe salts and is beneficial for P recovery in WWTPs.

Simultaneous removal of antibiotics and antibiotic resistance genes in wastewater by a novel nonthermal plasma/peracetic acid combination system: Synergistic performance and mechanism.

In this study, a novel and green method combining plasma with peracetic acid (plasma/PAA) was developed to simultaneously remove antibiotics and antibiotic resistance genes (ARGs) in wastewater, which achieves significant synergistic effects in the removal efficiencies and energy yield. At a plasma current of 2.6 A and PAA dosage of 10 mg/L, the removal efficiencies of most detected antibiotics in real wastewater exceeded 90 % in 2 min, with the ARG removal efficiencies ranging from 6.3 % to 75.2 %. The synergistic effects of plasma and PAA could be associated with the motivated production of reactive species (including •OH, •CH3, 1O2, ONOO-, •O2- and NO•), which decomposed antibiotics, killed host bacteria, and inhibited ARG conjugative transfer. In addition, plasma/PAA also changed the contributions and abundances of ARG host bacteria and downregulated the corresponding genes of two-component regulatory systems, thus reducing ARG propagation. Moreover, the weak correlations between the removal of antibiotics and ARGs highlights the commendable performance of plasma/PAA in the simultaneous removal of antibiotics and ARGs. Therefore, this study affords an innovative and effective avenue to remove antibiotics and ARGs, which relies on the synergistic mechanisms of plasma and PAA and the simultaneous removal mechanisms of antibiotics and ARGs in wastewater.

Highly efficient synthesis of mono-ß-1,6-Glucosylated Rebaudioside A derivative catalyzed by glycosyltransferase YjiC.

Steviol glycosides have attracted great interest because of their high levels of sweetness and safety, and absence of calories. Improvement of their sensory qualities via glycosylation modification by glycosyltransferase is a research hotspot. In this study, YjiC, a uridine diphosphate-dependent glycosyltransferase from Bacillus subtilis 168, was found with the ability to glycosylate rebaudioside A (Reb A) to produce a novel mono ß-1, 6-glycosylated Reb A derivative rebaudioside L2 (Reb L2). It has an improved sweetness compared with Reb A. Next, a cascade reaction was established by combining YjiC with sucrose synthase AtSuSy from Arabidopsis thaliana for scale-up preparation of Reb L2. It shows that Reb L2 (30.94 mg/mL) could be efficiently synthesized with an excellent yield of 91.34% within 12 h. Therefore, this study provides a potential approach for the production and application of new steviol glycoside Reb L2, expanding the scope of steviol glycosides.

Understanding roles of humic substance and protein on iron phosphate transformation during anaerobic fermentation of waste activated sludge.

Effects of fulvic acid (FA) and bovine serum albumin (BSA) on the transformation of ferric phosphate (FePO4) during anaerobic fermentation of waste activated sludge were investigated. Both FA and BSA promoted phosphorus (P) release from FePO4. A higher P release efficiency was achieved with FA addition compared with BSA at the same dose although BSA promoted iron (Fe) reduction more effectively. Both FA and BSA contributed to the enrichment of vivianite but hindered P re-precipitation with other ions, and FA affected more significantly. Microbial analysis revealed that FA contributed to the enrichment of iron-reducing bacteria (IRB) transporting electrons indirectly and increased the bioavailable Fe(III) via siderophores; BSA provided more electron donors, thereby enriched IRB transferring electrons directly to Fe(III). This study provides an in-depth understanding of Fe and P transformations in sludge bearing iron-phosphorus compounds and it is of practical value for P recovery as vivianite.