Improved photocatalytic oxidation of micropollutant in wastewater by solar light: assisted palladium-doped graphitic carbon nitride.

The escalating global industrial expansion has led to the extensive release of organic compounds into water bodies, resulting in substantial pollution and posing severe threats to both human health and the ecosystem. Among common micropollutants, bisphenol A (MP-BA) has emerged as a significant endocrine-disrupting chemical with potential adverse effects on human health and the environment. This study aims to develop an efficient photocatalyst, specifically by incorporating palladium-doped graphitic carbon nitride (Pd@GCN), to eliminate MP-BA pollutants present in industrial wastewater. The examination of optical properties and photoluminescence indicates that incorporating Pd into GCN enhances the visible light absorption spectra, which extends beyond 570 nm, and accelerates the separation rate of electron-hole pairs. The photocatalytic degradation efficiency of MP-BA increases from 81.7 to 98.8% as the solution pH rises from 5.0 to 9.0. Moreover, Pd@GCN significantly improves the removal rate of MP-BA in wastewater samples, reaching an impressive 92.8% after 60 min of exposure to solar light. Furthermore, the Pd@GCN photocatalyst exhibits notable reusability over six cycles of MP-BA degradation, indicating its promising potential for the treatment of organic pollutants in wastewater under solar light conditions.

Synthesis of solar-driven Cu-doped graphitic carbon nitride photocatalyst for enhanced removal of caffeine in wastewater.

Caffeine (CaF), a widely consumed compound, has been associated with various harmful effects on human health, including metabolic, cardiovascular disease, and reproductive disorders. Moreover, it poses a signifincant threat to organisms and aquatic ecosystems, leading to water pollution concerns. Therefore, the removal of CaF from wastewater is crucial for mitigating water pollution and minimizing its detrimental impacts on both humans and the environment. In this study, a solar-driven Cu-doped graphitic carbon nitride (Cu/CN) photocatalyst was synthesized and evaluated for its effectiveness in oxidizing CaF in wastewater. The Cu/CN photocatalyst, with a low band gap energy of 2.58eV, exhibited superior performance in degrading CaF compared to pure graphitic carbon nitride (CN). Under solar light irradiation, CuCN achieved a remarkable CaF degradation efficiency of 98.7% CaF, surpassing CN's efficiency of 74.5% by 24.2%. The synthesized Cu/CN photocatalyst demonstrated excellent removal capability, achieving a removal rate of over 88% for CaF in wastewater. Moreover, the reusability test showed that Cu/CN could be successfully reused up to five cycles maintaining a high removal efficiency of 74% for CaF in the fifth cycle. Additionally, the study elucidated the oxidation mechanism of CaF using solar-driven Cu/CN photocatalyst and highlighted the environmental implications of the process.

Graphitic carbon nitride metal-free photocatalyst for the simultaneous removal of emerging pharmaceutical pollutants in wastewater.

The presence of pharmaceutical pollutants in water has emerged as a significant public health concern due to their potential adverse impacts, including the development of antibiotic resistance. Consequently, advanced oxidation processes based on photocatalysis have garnered considerable attention for treating pharmaceutical contaminants in wastewater. In this study, graphitic carbon nitride (g-CN), a metal-free photocatalyst, was synthesized by the polymerization of melamine and assessed as a potential candidate for the photodegradation of acetaminophen (AP) and carbamazepine (CZ) in wastewater. Under alkaline conditions, g-CN demonstrated high removal efficiencies of 98.6% and 89.5% for AP and CZ, respectively. The relationships between degradation efficiency and catalyst dosage, initial pharmaceutical concentration, and photodegradation kinetics were investigated. Increasing the catalyst dose facilitated the removal of antibiotic contaminants, with an optimum catalyst dose of 0.1 g, achieving a photodegradation efficiency of 90.2% and 82.7% for AP and CZ, respectively. The synthesized photocatalyst removed over 98% of AP (1 mg/L) within 120 min, with a rate constant of 0.0321 min-1, 2.14 times faster than that of CZ. Quenching experiments revealed that g-CN was active under solar light and generated highly reactive oxidants such as hydroxyl (•OH) and superoxide (•O2-). The reuse test confirmed the good stability of g-CN for treating pharmaceuticals during three repeated cycles. Finally, the photodegradation mechanism and environmental impacts were discussed. This study presents a promising approach for treating and mitigating pharmaceutical contaminants in wastewater.

Effect of antibiotics and sanitizers on Salmonella biofilms associated with seafood contact surfaces.

This study investigates the effect of antibiotics and sanitizers on biofilm forming Salmonella isolated from different seafood contact surfaces. Four Salmonella were isolated from 384 swab samples collected from various contact surfaces of fishing boats, fish landing centres and seafood processing plants. One out of four isolates was from the fishing boat (FB I -1) other three isolates were from the seafood processing plant (FPPII -4, FPPII- 5, FPPI-3). The ability of Salmonella to form biofilms on different contact surfaces (HDPE, stainless steel, wood, glass, tiles) was tested with the microbial load on different incubation days, and a higher count was observed on day five. The effect of sanitizer viz., sodium hypochlorite (20, 50, 100, 200 mg/l) and iodophor (2, 5, 10 mg/l) on the biofilm formed on different seafood contact surfaces were investigated. A reduction of 2-3 log was observed on surfaces of HDPE and stainless steel when they were treated with a minimum of 5 mg/l of iodophor or 20 mg/l of sodium hypochlorite after a contact time of 5 min. Antibiotic resistance of biofilm forming Salmonella was tested for different classes of antibiotics (penicillin, ß-lactams, quinolones, macrolides, aminoglycosides, phenol drugs, sulfonamides, cephalosporin). All four isolates showed intermediate resistance to ciprofloxacin, a quinolone drug. Only one isolate FB I -1 (fishing boat deck) expressed resistance to more drugs, viz., ßlactams (AMC, AMP, penicillin G), macrolides (AZM) and nitrofurantoin (NIT). These findings shall help the seafood processors to mitigate the formation of Salmonella biofilms on various seafood contact surfaces with different sanitizers and the antibiotic resistance of biofilm forming Salmonella shall give knowledge on human clinical treatments. With this study, we shall recommend the regulatory authorities control the contamination level of fish handling areas.

Enhanced photodegradation of tetracycline in wastewater and conversion of CO2 by solar light assisted ZnO/g-C3N4.

Synthesized graphitic carbon nitride-based (CN) heterojunction photocatalysts are considered as a promising material for photodegradation of organic compounds and CO2 conversion. In this work, ZnO-loaded g-C3N4 (ZnO/CN) heterojunction photocatalyst was investigated for the enhanced photooxidation of tetracycline (TC) and CO2 conversion . After modification, the photocatalysts showed an improvement in the light absorption range and the photogenerated separation rate of electron/hole due to the heterojunction structure of ZnO/CN. The degradation rate of TC was found to be 92.6% within 60 min, while CO production rate was 7.68 µmol/g/h. The rate constants of TC by using ZnO/CN were 0.0812, 0.0539, 0.0336, 0.0249, and 0.0185 min-1, corresponding to the TC level of 1, 10, 30, 50, and 100 mg/L, respectively. The photodegradation rate of TC by ZnO/CN was 5 times higher than that of CN, demonstrating the advantage of heterojunction photocatalyst. The modified ZnO/CN exhibited superior degradation performance of TC and higher CO2 conversion rate than those of unmodified CN. It also exhibited high stability with 82% removal efficiency of TC at the 6th run and the CO2 conversion rate of 71% after reused 5 times. The heterojunction ZnO/CN can be utilized as an efficient material for various photocatalytic applications.

Enhanced Room-Temperature Ethanol Detection by Quasi 2D Nanosheets of an Exfoliated Polymeric Graphitized Carbon Nitride Composite-Based Patterned Sensor.

A novel room-temperature gas sensor composed of polymeric graphitic carbon nitride composite was fabricated and used for the detection of ethanol vapor under ambient conditions. Polymeric carbon nitride (PCN) microstructures composed of fluffy nanosheets were synthesized via a thermal polycondensation mechanism using melamine as the precursor, followed by vigorous chemical exfoliation. These sheet-like microstructures were employed as active materials in the form of composites, along with carbon paste consisting of graphite nanoplatelets and carbon black. The active sensing layer was fabricated on a PET sheet and assembled on an interdigitated gold electrode. The as-fabricated sensor exhibited excellent sensing efficiency (>100% response at 10 ppm) along with high selectivity and stability. In particular, for ultralow concentrations such as 1 ppm (>10% response), this resistive-based sensor exhibited a swift response time provided under ambient conditions. The exfoliated PCN composite sensor was found to be working with appreciable efficiency at moderate relative humidity (%) with the least fluctuation in response signals also demonstrating long-term stability for 30 days with consistent response signals.

Synthesis and Corrosion Inhibition Potential of Cerium/Tetraethylenepentamine Dithiocarbamate Complex on AA2024-T3 in 3.5% NaCl.

In this work, a cerium/tetraethylenepentamine dithiocarbamate complex was synthesized and evaluated for the corrosion inhibition capability on an AA2024-T3 Al alloy in a 3.5% NaCl medium. The synthesized compounds were characterized via spectroscopic techniques. The corrosion inhibition behaviour of the complex was elucidated by electrochemical measurements and surface analysis techniques. Based on electrochemical test results, the corrosion inhibition efficiency of the complex increases with the immersion time of aluminium alloy in the test solution. The corrosion inhibition reaches 96.80% when the aluminium is immersed in a 3.5% NaCl solution containing a corrosion inhibitor for 120 h. The potentiodynamic polarization test results show that the complex acts as a mixed-type corrosion inhibitor and the passive range is widened. The surface analysis methods reveal that the corrosion inhibition ability of the complex originated from the formation of a protective layer on the Al surface. This film is created from the physisorption and chemisorption of cerium ions and organic parts simultaneously released from the complex molecules.

Photodegradation of ciprofloxacin antibiotic in water by using ZnO-doped g-C3N4 photocatalyst.

Ciprofloxacin antibiotic (CIP) is one of the antibiotics with the highest rate of antibiotic resistance, if used and managed improperly, can have a negative impact on the ecosystem. In this research, ZnO modified g-C3N4 photocatalyst was prepared and applied for the decomposition of CIP antibiotic compounds in water. The removal performance of CIP by using ZnO/g-C3N4 reached 93.8% under pH 8.0 and an increasing amount of catalyst could improve the degradation performance of the pollutant. The modified ZnO/g-C3N4 completely oxidized CIP at a low concentration of 1 mg L-1 and the CIP removal efficiency slightly decreases (around 13%) at a high level of pollutant (20 mg L-1). The degradation rate of CIP by doped sample ZnO/g-C3N4 was 4.9 times faster than that of undoped g-C3N4. The doped catalyst ZnO/g-C3N4 also displayed high reusability for decomposition of CIP with 89.8% efficiency remaining after 3 cycles. The radical species including ·OH, ·O2- and h+ are important in the CIP degradation process. In addition, the proposed mechanism for CIP degradation by visible light-assisted ZnO/g-C3N4 was claimed.

Alginate-modified biochar derived from rice husk waste for improvement uptake performance of lead in wastewater.

In this work, alginate-modified biochar derived from rice husk waste was synthesized using a simple process. The modified biochar (MBC) and rice husk biochar (RhBC) were investigated for removing Pb (II) ions in wastewater. The BET result displayed significantly improved specific surface area of MBC up to 120 m2/g along with a total pore volume of 0.653 cm3/g. FTIR spectrums presented the higher oxygen-contained functional groups of MBC as compared to RhBC, resulting in increasing adsorption capacity of Pb (II). MBC had higher adsorption capacity (112.3 mg/g) and faster removal rate (0.0081 g mg-1 min-1) than those of RhBC (41.2 mg/g and 0.00025 g mg-1 min-1). Modified RhBC can remove more than 99% of Pb (II) from wastewater and it could be utilized for three cycles with a removal performance of over 90%. In addition, the Pb adsorption mechanism by using MBC was proposed and the practical application of MBC for the treatment of wastewater in Vietnam was discussed.

TiO2 nanoparticles derived from egg shell waste: Eco synthesis, characterization, biological and photocatalytic applications.

Biosynthesis of metal oxide nanoparticles has attracted much attention in recent years owing to the increasing impact for improving hygienic substances, cost effective approaches, environment friendly solvents and reusable resources. The present study has shown the eco synthesis of TiO2 nanoparticles using the aqueous extract of egg shell waste. UV, XRD, FT-IR, and FE-SEM with EDX methods were implied for TiO2 nanoparticles. The agar well approach was used to investigate the antimicrobial properties of biosynthesized nanoparticles against pathogenic organisms. The cytotoxicity analysis was investigated by MTT assay method and photocatalytic activity was studied using methylene blue, methyl orange and Congo red dye. X-ray diffraction studies showed that the presence of tetragonal structure. The crystallite size of synthesized TiO2 nanoparticles is 27.3 nm. FE-SEM analysis indicates that the average grain size of the prepared sample was found to be in the range of 30-40 nm. Eco synthesis of TiO2 nanoparticles displayed amazing antimicrobial efficacies against human pathogenic organisms and obtained excellent cytotoxicity investigation was performed against Osteosarcoma cell lines (MG-63). Further it was also found that the expression of impressive catalytic efficiency, 91.1 percent decreased in 60 min for methylene blue. From the results, we found that eco synthesized TiO2 nanoparticles has promising utility in multidisciplinary like antimicrobial, anticancer and photocatalytic applications.

Study of synergistic effect of cobalt and carbon codoped with TiO2 photocatalyst for visible light induced degradation of phenol.

In this work, we reported synthesis of cobalt and carbon codoped TiO2 (Co-C-TiO2) nanoparticles were prepared using co-precipitation technique. The synthesized catalysts are analyzed by various methods. The powder XRD pattern confirmed that all the samples were polycrystalline of anatase phase and particle size of resultant nanoparticle was reduced correlated with bare TiO2 sample. FTIR measurements exhibit the identification of functional groups present at the surface of TiO2. FESEM micrograph showed that the shape of codoped TiO2 nanoparticles are approximately sphere. The attained energy gap of Co doped and C codoping of TiO2 modifies to a level below the energy gap of TiO2 anatase specifying a high capability to absorb visible light. The recombination rate of photo-induced electrons and holes for Co-C codoped TiO2 nanoparticles is significantly reduced. The synthesized samples are assessed in degradation of phenol by the illumination of visible light. The results confirmed that photocatalytic activity enhanced due to doping and codoping of Co and C. As a result, Co-C codoped TiO2 nanoparticles exhibited a higher visible-light photocatalytic activity in compared with Co-TiO2 and bare TiO2 with the maximum degradation efficiency of 98, 75 and 15%, respectively. And also, the reusability of the catalyst was proved when 95% degradation could be achieved after consecutive batches. It is predictable that this work will provide new insights to increase the visible light active photocatalysts for environmental problems.

Improved photodegradation of antibiotics pollutants in wastewaters by advanced oxidation process based on Ni-doped TiO2.

The number of antibiotic compounds in wastewaters has been growing globally due to the covid-19 problem. Using antibiotics to treat the patients would produce larger amounts of these compounds into the environment with negative impacts. Hence, finding out the method for the elimination of toxic organic pollutants as well as antibiotics in water is urgent (In this study, the treatment of antibiotic pollutants including cefalexin (CF) and tetracycline (TC) was investigated by applying the advanced oxidation process based on Ni-doped TiO2 (Ni-TiO2). The characterizations technologies such as XRD, XPS, UV-vis, PL, and PC indicated that Ni doping would improve the photocatalytic performance of TiO2. In the photodegradation experiments, the Ni-TiO2 possessed high photocatalytic degradation efficiencies with 93.6% for CF and 82.5% for TC. Besides, the removal rates of antibiotics after five cycles are higher than 75%, implying excellent stability of Ni-TiO2 photocatalyst. The result from the treatment of wastewater samples revealed that the Ni-TiO2 photocatalytic had good performance for removal of CF and TC at a high level of 88.6 and 80.2%, respectively.

Visible-light photocatalysis of Ag-doped graphitic carbon nitride for photodegradation of micropollutants in wastewater.

This work reports on graphitic carbon nitride (C3N4) modified with silver to investigate its visible-light-driven photocatalysis for decomposition of micropollutants in wastewater. Various characterization methods were conducted to examine the physico-chemical properties of Ag-doped C3N4 (Ag-C3N4) photocatalyst. The results from structural, morphological, and surface chemical analysis indicated that C3N4 was successfully doped with Ag. Photoluminescence and transient photocurrent density studies revealed that the recombination rate of electron-hole pairs was reduced, leading to the enhancement of photocatalytic activities of the photocatalyst. Ag-C3N4 showed high photocatalytic performance for photodegradation of our target micropollutant, bisphenol A (BA). It could completely remove BA in 1 h with kinetic constant 6.2 times higher than that of the undoped C3N4 photocatalyst. Recycling test and the assessment of the photocatalyst in wastewater further confirmed the excellent stability and applicability of the Ag-C3N4 photocatalyst. This work could provide a new solution to the practical application of photocatalyts for the degradation of micropollutants in wastewater.

Biosorbent derived from coffee husk for efficient removal of toxic heavy metals from wastewater.

In this study, we investigated the feasibility on the utilization of coffee husk as biosorbents for the removal of heavy metal ions such as Pb2+ and Cd2+ from wastewater. Biochar was produced from coffee wastes and modified with sodium hydroxide to create functional groups on the surface and increase the specificic surface area. The resultant products were characterized by using various analytical methods such as scanning electron microscopy, specific area, surface functional group and zeta potential analysis. The as-prepared materials were employed as adsorbent to remove Pb2+ and Cd2+ ions from wastewater. The maximum sorption capacities of biosorbents were measured to be 116.3 and 139.5 mg g-1 for Cd2+ and Pb2+, respectively, which is comparable to the conventional adsorbents. Kinetic studies showed that the sorption of Pb2+ and Cd2+ on biosorbents can be described by the Freundlich isotherm and second-order kinetic model. The coffee husk-derived biosorbent was capable of removing 89.6% of Pb2+ and 81.5% Cd2+ ions from wastewater, and therefore can be considered as low-cost and efficient adsorbent to remove heavy metal ions from wastewater.

Enhanced recovery of phosphate as a value-added product from wastewater by using lanthanum modified carbon-fiber.

The aim of this study is to present the potential of activated carbon fiber (CF) impregnated with lanthanum (La) as a novel adsorbent (La-CF) of phosphate-phosphorus (P) and to assess the value-added due to P-recovery from wastewater using La-CF. The CF were loaded with La and the loaded CF was then calcined at 500 °C. The La-CF adsorbent was used in a series of batch experiments to characterize the adsorption of P at pH of 6-10 and P concentrations of 1-200 mg/L. Physical-chemical properties such as surface morphology, surface charge, surface area, and surface chemistry were determined for the La-CF. The La-CF exhibited adsorption capacity of 196.5 mg/g, fast sorption kinetics and high selectivity for P removal from aqueous solution. La-CF removed 97.3% of P from wastewater and achieved P-level to below 2 mg/L. It was repetitively reused over 10 times in successive cycles to remove P from wastewater. The value-added by recovery of P from wastewater was calculated at around 0.12 US$/L, demonstrating economic benefits of La-CF. In conclusion, the successful removal, recycling, and recovery value-added of P using La-CF adsorbent displayed good potential for developing the technology for treatment of wastewaters to recover valuable compounds such as phosphorus.

Adsorptive removal and recovery of organic pollutants from wastewater using waste paper-derived carbon-based aerogel.

In this study, carbon-based aerogels derived from waste paper (CWP) were explored as an efficent adsorbent to remove organic pollutants including phenol (Ph) and 2-chlorophenol (2CP) from wastewater. CWP exhibited a highly porous structure and large specific surface area of 892 m2 g-1, which facilitated the adsorption of Ph and 2CP in wastewater. The adsorption behavior of Ph and 2CP on CWP could be well described by the pseudo-second-order kinetics and Langmuir isotherm models. Based on the Langmuir isotherm, the maximum adsorption capacities of CWP for Ph and 2CP were 238 and 278 mg g-1, respectively, and these values were much higher than those of other adsorbents. The removal of the organic pollutants mainly occurred through electrostatic attraction, pore-filling, hydrogen bonding, and π-π interactions. The CWP can be directly applied for the removal of Ph and 2CP at low concentration (<200 mg L-1) in the wastewater, while they can be used with additional pre-treatment for wastewater containing high concentration of organic pollutants. The adsorptive recovery of organic compounds and potential reuse of treated wastewater were also discussed. This work provides an efficient approach to produce effective adsorbent for the removal and recovery of chemicals from wastewater.

Hypothermia from a two-component mixture comprising Amoxicillin and Sulbactam.

Hypothermia might be an adverse effect of Amoxicillin and/or Sulbactam, and clinicians should be aware of this effect. Further clinical and laboratory investigations are also needed to confirm and clarify the underlying mechanism of this side effect.

Polygonum multiflorum root extract as a potential candidate for treatment of early graying hair.

Despite Polygonum multiflorum (PM) has been experiencely used as a drug to treat early graying hair phenomenon in Asian countries for a long time, there is limited study examined the real biological effects of PM on hair graying in vitro and in vivo. In this study, we investigated the effects of PM root extract (PM-RE) on melanin synthesis in human melanoma SKMEL-28 cells and embryos/larvae of wild-type strain AB zebrafish. We also preliminary revealed the molecular mechanism of early hair graying phenomenon in both in vitro and in vivo models. Our results showed that PM-RE significantly induced melanin synthesis in melanin-producing SKMEL-28 melanoma cells and also in zebrafish embryos/larvae at 4-day postfertilization through activation of MC1R/MITF/tyrosinase-signaling pathway. We also investigated the differences in genotype between graying hair follicle and black hair follicle of young peoples and found that early hair graying phenomenon may be related to downregulation of MC1R/MITF/tyrosinase pathway. Taken together, we suggested that PM-RE at safe doses could be used as a potential agent for the treatment of early hair graying and other loss pigmentation-related diseases.

Replenishing the cyclic-di-AMP pool: regulation of diadenylate cyclase activity in bacteria.

Bacteria can sense environmental cues and alter their physiology accordingly through the use of signal transduction pathways involving second messenger nucleotides. One broadly conserved second messenger is cyclic-di-AMP (c-di-AMP) which regulates a range of processes including cell wall homeostasis, potassium uptake, DNA repair, fatty acid synthesis, biofilm formation and central metabolism in bacteria. The intracellular pool of c-di-AMP is maintained by the activities of diadenylate cyclase (DAC) and phosphodiesterase (PDE) enzymes, as well as possibly via c-di-AMP export. Whilst extracellular stimuli regulating c-di-AMP levels in bacteria are poorly understood, recent work has identified effector proteins which directly interact and alter the activity of DACs. These include the membrane bound CdaR and the phosphoglucosamine mutase GlmM which both bind directly to the membrane bound CdaA DAC and the recombination protein RadA which binds directly to the DNA binding DisA DAC. The genes encoding these multiprotein complexes are co-localised in many bacteria providing further support for their functional connection. The roles of GlmM in peptidoglycan synthesis and RadA in Holliday junction intermediate processing suggest that c-di-AMP synthesis by DACs will be responsive to these cellular activities. In addition to these modulatory interactions, permanent dysregulation of DAC activity due to suppressor mutations can occur during selection to overcome growth defects, rapid cell lysis and osmosensitivity. DACs have also been investigated as targets for the development of new antibiotics and several small compound inhibitors have recently been identified. This review aims to provide an overview of how c-di-AMP synthesis by DACs can be regulated.

Cyclic-di-AMP synthesis by the diadenylate cyclase CdaA is modulated by the peptidoglycan biosynthesis enzyme GlmM in Lactococcus lactis.

The second messenger cyclic-di-adenosine monophosphate (c-di-AMP) plays important roles in growth, virulence, cell wall homeostasis, potassium transport and affects resistance to antibiotics, heat and osmotic stress. Most Firmicutes contain only one c-di-AMP synthesizing diadenylate cyclase (CdaA); however, little is known about signals and effectors controlling CdaA activity and c-di-AMP levels. In this study, a genetic screen was employed to identify components which affect the c-di-AMP level in Lactococcus. We characterized suppressor mutations that restored osmoresistance to spontaneous c-di-AMP phosphodiesterase gdpP mutants, which contain high c-di-AMP levels. Loss-of-function and gain-of-function mutations were identified in the cdaA and gdpP genes, respectively, which led to lower c-di-AMP levels. A mutation was also identified in the phosphoglucosamine mutase gene glmM, which is commonly located within the cdaA operon in bacteria. The glmM I154F mutation resulted in a lowering of the c-di-AMP level and a reduction in the key peptidoglycan precursor UDP-N-acetylglucosamine in L. lactis. C-di-AMP synthesis by CdaA was shown to be inhibited by GlmM(I154F) more than GlmM and GlmM(I154F) was found to bind more strongly to CdaA than GlmM. These findings identify GlmM as a c-di-AMP level modulating protein and provide a direct connection between c-di-AMP synthesis and peptidoglycan biosynthesis.