Genome-wide analysis of in vivo-evolved Candida auris reveals multidrug-resistance mechanisms.

Candida auris, an emerging and multidrug-resistant fungal pathogen, has led to numerous outbreaks in China. While the resistance mechanisms against azole and amphotericin B have been studied, the development of drug resistance in this pathogen remains poorly understood, particularly in in vivo-generated drug-resistant strains. This study employed pathogen whole-genome sequencing to investigate the epidemiology and drug-resistance mutations of C. auris using 16 strains isolated from two patients. Identification was conducted through Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and antimicrobial susceptibilities were assessed using broth microdilution and Sensititre YeastOne YO10. Whole-genome sequencing revealed that all isolates belonged to the South Asian lineage, displaying genetic heterogeneity. Despite low genetic variability among patient isolates, notable mutations were identified, including Y132F in ERG11 and A585S in TAC1b, likely linked to increased fluconazole resistance. Strains from patient B also carried F214L in TAC1b, resulting in a consistent voriconazole minimum inhibitory concentration of 4 µg/mL across all isolates. Furthermore, a novel frameshift mutation in the SNG1 gene was observed in amphotericin B-resistant isolates compared to susceptible ones. Our findings suggest the potential transmission of C. auris and emphasize the need to explore variations related to antifungal resistance. This involves analyzing genomic mutations and karyotypes, especially in vivo, to compare sensitive and resistant strains. Further monitoring and validation efforts are crucial for a comprehensive understanding of the mechanisms of drug resistance in C. auris.

Emergence and clonal expansion of Aeromonas hydrophila ST1172 that simultaneously produces MOX-13 and OXA-724.

BACKGROUND: Aeromonas hydrophila infections can cause gastrointestinal symptoms such as diarrhea; however, deep infections are rarely reported. Outbreaks of A. hydrophila are reported more frequently in fish, poultry, and snakes than in humans. This study aimed to track clonal relatedness of deep infections caused by A. hydrophila using whole genome sequencing (WGS). METHODS: We collected three isolates of A. hydrophila in July 19 to August 29, 2019, from patients that underwent spine surgery. Accurate species identification was performed using whole-genome average nucleotide identity (ANI). Antimicrobial susceptibility testing was performed using a VITEK 2 automated AST-N334 Gram-negative susceptibility card system. Antimicrobial resistance and virulence genes were identified using the Comprehensive Antibiotic Resistance Database and Virulence Factor Database VFanalyzer. RESULTS: All three isolates were identified as A. hydrophila based on ANI and multilocus sequence typing analysis revealed that A. hydrophila belonged to a novel sequence type (ST1172). All three isolates were susceptible to amikacin and levofloxacin; however, they were resistant to piperacillin/tazobactam, ceftriaxone, cefuroxime, cefoxitin, and imipenem. Isolate 19W05620 (patient 3) showed increased ceftazidime resistance (minimum inhibitory concentration ≥ 64 µg/mL). All three isolates possessed the same chromosomally encoded ß-lactamases, including blaOXA-724 (ß-lactamase), imiH (metallo-ß-lactamase), and blaMOX-13 (AmpC) in plasmids. CONCLUSIONS: Our study validated the transmission of a novel carbapenem-resistant A. hydrophila sequence type (ST1172) in patients that underwent spine surgery. Control measures should be developed to prevent dissemination of A. hydrophila in the hospital setting.

Multicenter comparative genomic study of Klebsiella oxytoca complex reveals a highly antibiotic-resistant subspecies of Klebsiellamichiganensis.

BACKGROUND: The Klebsiella oxytoca complex is an opportunistic pathogen that has been recently identified as an actual complex. However, the characteristics of each species remain largely unknown. We aimed to study the clinical prevalence, antimicrobial profiles, genetic differences, and interaction with the host of each species of this complex. METHODS: One hundred and three clinical isolates of the K. oxytoca complex were collected from 33 hospitals belonging to 19 areas in China from 2020 to 2021. Species were identified using whole genome sequencing based on average nucleotide identity. Clinical infection characteristics of the species were analyzed. Comparative genomics and pan-genome analyses were performed on these isolates and an augmented dataset, including 622 assemblies from the National Center for Biotechnology Information. In vitro assays evaluating the adhesion ability of human respiratory epithelial cells and survivability against macrophages were performed on randomly selected isolates. RESULTS: Klebsiella michiganensis (46.6%, 48/103) and K. oxytoca (35.92%, 37/103) were the major species of the complex causing human infections. K. michiganensis had a higher genomic diversity and larger pan-genome size than did K. oxytoca. K. michiganensis isolates with blaoxy-5 had a higher resistance rate to various antibiotics, antimicrobial gene carriage rate, adhesion ability to human respiratory epithelial cells, and survival rate against macrophages than isolates of other species. CONCLUSION: Our study revealed the genetic diversity of K. michiganensis and firstly identified the highly antimicrobial-resistant profile of K. michiganensis carrying blaoxy-5.

Antifungal susceptibility profile and local epidemiological cut-off values of Yarrowia (Candida) lipolytica: an emergent and rare opportunistic yeast.

IMPORTANCE: Yarrowia lipolytica, also known as Candida lipolytica, is an emerging opportunistic "rare pathogenic yeast". Due to the limited data on its antifungal susceptibility, the clinical treatments become challenging. Based on the China Hospital Invasive Fungal Surveillance Network (2009-2022), we conducted a comprehensive multi-method study on clinical isolates from various central hospitals. This study is currently the largest study carried out to assess the antifungal susceptibility of Y. lipolytica. It is also the first to establish local epidemiological cut-off values (L-ECOFFs), identify its ERG11 mutations, and assess the consistency between the three prevalent commercial antifungal susceptibility testing methods and the broth microdilution method. We recommend the Sensititre YeastOne as the best option for antifungal susceptibility testing for Y. lipolytica, followed by the ATB FUNGUS 3. Nevertheless, practitioners should use the MIC test strip with discretion.

The first established microsatellite markers to distinguish Candida orthopsilosis isolates and detection of a nosocomial outbreak in China.

The infection proportion of Candida orthopsilosis, a member of the C. parapsilosis complex, has increased globally in recent years, and nosocomial outbreaks have been reported in several countries. This study aimed to establish microsatellite loci-based typing method that was able to effectively distinguish among C. orthopsilosis isolates. Three reference C. orthopsilosis genome sequences were analyzed to identify repeat loci. DNA sequences containing over eight bi- or more nucleotide repeats were selected. A total of 51 loci were initially identified, and locus-specific primers were designed and tested with 20 epidemiologically unrelated isolates. Four loci with excellent reproducibility, specificity, and resolution for molecular typing purposes were identified, and the combined discriminatory power (DP, based on 20 epidemiologically unrelated isolates) of these four loci was 1.0. Reproducibility was demonstrated by consistently testing three strains each in triplicate, and stability, demonstrated by testing 10 successive passages. Then, we collected 48 C. orthopsilosis non-duplicate clinical isolates from the China Hospital Invasive Fungal Surveillance Net study to compare the DP of the microsatellite-based typing with internal transcribed spacer (ITS) and amplified fragment length polymorphism (AFLP) typing analyses, using ATCC 96139 as a reference strain. These 49 isolates were subdivided into 12 microsatellite types (COMT1-12), six AFLP types, and three ITS types, while all the isolates with the same COMT belonged to consistent AFLP and ITS type, demonstrating the high DP of our microsatellite-type method. According to our results, COMT12 was found to be the predominant type in China, and COMT5 was the second largest and responsible for causing a nosocomial outbreak. This microsatellite-type method is a valuable tool for the differentiation of C. orthopsilosis and could be vital for epidemiological studies to determine strain relatedness and monitor transmission.

Clonal Dissemination of Antifungal-Resistant Candida haemulonii, China.

Candida haemulonii, a relative of C. auris, frequently shows antifungal resistance and is transmissible. However, molecular tools for genotyping and investigating outbreaks are not yet established. We performed genome-based population analysis on 94 C. haemulonii strains, including 58 isolates from China and 36 other published strains. Phylogenetic analysis revealed that C. haemulonii can be divided into 4 clades. Clade 1 comprised strains from China and other global strains; clades 2-4 contained only isolates from China, were more recently evolved, and showed higher antifungal resistance. Four regional epidemic clusters (A, B, C, and D) were identified in China, each comprising ≥5 cases (largest intracluster pairwise single-nucleotide polymorphism differences <50 bp). Cluster A was identified in 2 hospitals located in the same city, suggesting potential intracity transmissions. Cluster D was resistant to 3 classes of antifungals. The emergence of more resistant phylogenetic clades and regional dissemination of antifungal-resistant C. haemulonii warrants further monitoring.

Emergence of Antifungal Resistant Subclades in the Global Predominant Phylogenetic Population of Candida albicans.

Candida albicans remains the most common species causing invasive candidiasis. In this study, we present the population structure of 551 global C. albicans strains. Of these, the antifungal susceptibilities of 370 strains were tested. Specifically, 66.6% of the azole-nonsusceptible (NS)/non-wild-type (NWT) strains that were tested belonged to Clade 1. A phylogenetic analysis, a principal components analysis, the population structure, and a loss of heterozygosity events revealed two nested subclades in Clade 1, namely, Clade 1-R and Clade 1-R-α, that exhibited higher azole-NS/NWT rates (75.0% and 100%, respectively). In contrast, 6.4% (21/326) of the non-Clade 1-R isolates were NS/NWT to at least 1 of 4 azoles. Notably, all of the Clade 1-R-α isolates were pan-azole-NS/NWT that carried unique A114S and Y257H double substitutions in Erg11p and had the overexpression of ABC-type efflux pumps introduced by the substitution A736V in transcript factor Tac1p. It is worth noting that the Clade 1-R and Clade 1-R-α isolates were from different cities that are distributed over a large geographic span. Our study demonstrated the presence of specific phylogenetic subclades that are associated with antifungal resistance among C. albicans Clade 1, which calls for public attention on the monitoring of the future spread of these clones. IMPORTANCE Invasive candidiasis is the most common human fungal disease among hospitalized patients, and Candida albicans is the predominant pathogen. Considering the large number of infected cases and the limited alternative therapies, the azole-resistance of C. albicans brings a huge clinical threat. Here, our study suggested that antifungal resistance in C. albicans could also be associated with phylogenetic lineages. Specifically, it was revealed that more than half of the azole-resistant C. albicans strains belonged to the same clade. Furthermore, two nested subclades of the clade exhibited extremely high azole-resistance. It is worth noting that the isolates of two subclades were from different cities that are distributed over a large geographic span in China. This indicates that the azole-resistant C. albicans subclades may develop into serious public health concerns.

First two fungemia cases caused by Candida haemulonii var. vulnera in China with emerged antifungal resistance.

Candida haemulonii var. vulnera is a rare variant of C. haemulonii, which has been previously reported to cause human infections. Owing to the close kinship between C. haemulonii sensu stricto and C. haemulonii var. vulnera, accurate identification of C. haemulonii var. vulnera relied on DNA sequencing assay targeting, for example, rDNA internal transcribed spacer (ITS) region. In this work, two strains of C. haemulonii var. vulnera were collected from the China Hospital Invasive Fungal Surveillance Net (CHIF-NET). The identification capacity of three matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and VITEK 2 YST ID biochemical methods were evaluated against ITS sequencing. In addition, antifungal susceptibility testing was performed using Sensititre YeastOne. Moreover, we comprehensively screened drug-resistant related genes by whole-genome sequencing. The two strains were not correctly identified to species variant level using MALDI-TOF MS and YST ID cards. Both strains were resistant to amphotericin B (minimum inhibitory concentration [MIC] > 2 µg/ml). Moreover, strain F4564 and F4584 exhibited high MIC to fluconazole (>256 µg/ml) and 5-flucytosine (>64 µg/ml), respectively, which were supposed to result from key amino acid substitutions Y132F and G307A in Erg11p and V58fs and G60K substitutions in Fur1p. The rare species C. haemulonii var. vulnera has emerged in China, and such drug-resistant fungal species that can cause invasive diseases require further close attention.

Antifungal susceptibility profiles and drug resistance mechanisms of clinical Candida duobushaemulonii isolates from China.

Candida duobushaemulonii, type II Candida haemulonii complex, is closely related to Candida auris and capable of causing invasive and non-invasive infections in humans. Eleven strains of C. duobushaemulonii were collected from China Hospital Invasive Fungal Surveillance Net (CHIF-NET) and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF), VITEK 2 Yeast Identification Card (YST), and internal transcribed spacer (ITS) sequencing. Whole genome sequencing of C. duobushaemulonii was done to determine their genotypes. Furthermore, C. duobushaemulonii strains were tested by Sensititre YeastOne™ and Clinical and Laboratory Institute (CLSI) broth microdilution panel for antifungal susceptibility. Three C. duobushaemulonii could not be identified by VITEK 2. All 11 isolates had high minimum inhibitory concentrations (MICs) to amphotericin B more than 2 µg/ml. One isolate showed a high MIC value of ≥64 µg/ml to 5-flucytosine. All isolates were wild type (WT) for triazoles and echinocandins. FUR1 variation may result in C. duobushaemulonii with high MIC to 5-flucytosine. Candida duobushaemulonii mainly infects patients with weakened immunity, and the amphotericin B resistance of these isolates might represent a challenge to clinical treatment.

Persistence of an epidemic cluster of Rhodotorula mucilaginosa in multiple geographic regions in China and the emergence of a 5-flucytosine resistant clone.

Rhodotorula mucilaginosa, an environmental yeast widely used in industry and agriculture, is also an opportunistic pathogen resistant to multi-antifungals. During the national surveillance in China, R. mucilaginosa has been documented from various hospitals and regions. At present, the molecular epidemiology of invasive infections caused by R. mucilaginosa and their resistance profiles to antifungals were unknown. Here we collected 49 strains from four hospitals located in different geographic regions from 2009 to 2019 in China, determined their genotypes using different molecular markers and quantified susceptibilities to various antifungals. Sequencing of ITS and D1/D2 regions in rDNA indicated that 73.5% (36/49) of clinical strains belong to same sequence type (rDNA type 2). Microsatellite (MT) genotyping with 15 (recently developed) tandem repeat loci identified 5 epidemic MT types, which accounted for 44.9% (22/49) of clinical strains, as well as 27 sporadic MT types. Microsatellite data indicated that the presence of an epidemic cluster including 35 strains (71.4%) repeatedly isolated in four hospitals for eight years. Single nucleotide variants (SNVs) from the whole genome sequence data also supported the clustering of these epidemic strains due to low pairwise distance. In addition, phylogenetic analysis of SNVs from these clinical strains, together with environmental and animal strains showed that the closely related epidemic cluster strains may be opportunistic, zoonotic pathogens. Also, molecular data indicated a possible clonal transmission of pan echinocandins-azoles-5-flucytosine resistant R. mucilaginosa strains in hospital H01. Our study demonstrated that R. mucilaginosa is a multi-drug resistant pathogen with the ability to cause nosocomial infection.

Antifungal Susceptibility Profiles and Resistance Mechanisms of Clinical Diutina catenulata Isolates With High MIC Values.

Diutina catenulata (Candida catenulata) is an ascomycete yeast species widely used in environmental and industrial research and capable of causing infections in humans and animals. At present, there are only a few studies on D. catenulata, and further research is required for its more in-depth characterization and analysis. Eleven strains of D. catenulata collected from China Hospital Invasive Fungal Surveillance Net (CHIF-NET) and the CHIF-NET North China Program were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry and internal transcribed spacer sequencing. The antifungal susceptibility of the Diutina catenulata strains was tested using the Clinical and Laboratory Standards Institute broth microdilution method and Sensititre YeastOne™. Furthermore, ERG11 and FKS1 were sequenced to determine any mutations related to azole and echinocandin resistance in D. catenulata. All isolates exhibited low minimum inhibitory concentration (MIC) values for itraconazole (0.06-0.12 µg/ml), posaconazole (0.06-0.12 µg/ml), amphotericin B (0.25-1 µg/ml), and 5-flucytosine (range, <0.06-0.12 µg/ml), whereas four isolates showed high MICs (≥4 µg/ml) for echinocandins. Strains with high MIC values for azoles showed common ERG11 mutations, namely, F126L/K143R. In addition, L139R mutations may be linked to high MICs of fluconazole. Two amino acid alterations reported to correspond to high MIC values of echinocandin, namely, F621I (F641) and S625L (S645), were found in the hot spot 1 region of FKS1. In addition, one new amino acid alteration, I1348S (I1368), was found outside of the FKS1 hot spot 2 region, and its contribution to echinocandin resistance requires future investigation. Diutina catenulata mainly infects patients with a weak immune system, and the high MIC values for various antifungals exhibited by these isolates may represent a challenge to clinical treatment.

Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) Analysis for the Identification of Pathogenic Microorganisms: A Review.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used in the field of clinical microbiology since 2010. Compared with the traditional technique of biochemical identification, MALDI-TOF MS has many advantages, including convenience, speed, accuracy, and low cost. The accuracy and speed of identification using MALDI-TOF MS have been increasing with the development of sample preparation, database enrichment, and algorithm optimization. MALDI-TOF MS has shown promising results in identifying cultured colonies and rapidly detecting samples. MALDI-TOF MS has critical research applications for the rapid detection of highly virulent and drug-resistant pathogens. Here we present a scientific review that evaluates the performance of MALDI-TOF MS in identifying clinical pathogenic microorganisms. MALDI-TOF MS is a promising tool in identifying clinical microorganisms, although some aspects still require improvement.

Evaluation of Autof MS 1000 and Vitek MS MALDI-TOF MS System in Identification of Closely-Related Yeasts Causing Invasive Fungal Diseases.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been accepted as a rapid, accurate, and less labor-intensive method in the identification of microorganisms in clinical laboratories. However, there is limited data on systematic evaluation of its effectiveness in the identification of phylogenetically closely-related yeast species. In this study, we evaluated two commercially available MALDI-TOF systems, Autof MS 1000 and Vitek MS, for the identification of yeasts within closely-related species complexes. A total of 1,228 yeast isolates, representing 14 different species of five species complexes, including 479 of Candida parapsilosis complex, 323 of Candida albicans complex, 95 of Candida glabrata complex, 16 of Candida haemulonii complex (including two Candida auris), and 315 of Cryptococcus neoformans complex, collected under the National China Hospital Invasive Fungal Surveillance Net (CHIF-NET) program, were studied. Autof MS 1000 and Vitek MS systems correctly identified 99.2% and 89.2% of the isolates, with major error rate of 0.4% versus 1.6%, and minor error rate of 0.1% versus 3.5%, respectively. The proportion of isolates accurately identified by Autof MS 1000 and Vitek MS per each yeast complex, respectively, was as follows; C. albicans complex, 99.4% vs 96.3%; C. parapsilosis complex, 99.0% vs 79.1%; C glabrata complex, 98.9% vs 94.7%; C. haemulonii complex, 100% vs 93.8%; and C. neoformans, 99.4% vs 95.2%. Overall, Autof MS 1000 exhibited good capacity in yeast identification while Vitek MS had lower identification accuracy, especially in the identification of less common species within phylogenetically closely-related species complexes.

BioAIEgens derived from rosin: how does molecular motion affect their photophysical processes in solid state?

The exploration of artificial luminogens with bright emission has been fully developed with the advancement of synthetic chemistry. However, many of them face problems like weakened emission in the aggregated state as well as poor renewability and sustainability. Therefore, the development of renewable and sustainable luminogens with anti-quenching function in the solid state, as well as to unveil the key factors that influence their luminescence behavior become highly significant. Herein, a new class of natural rosin-derived luminogens with aggregation-induced emission property (AIEgens) have been facilely obtained with good biocompatibility and targeted organelle imaging capability as well as photochromic behavior in the solid state. Mechanistic study indicates that the introduction of the alicyclic moiety helps suppress the excited-state molecular motion to enhance the solid-state emission. The current work fundamentally elucidates the role of alicyclic moiety in luminogen design and practically demonstrates a new source to large-scalely obtain biocompatible AIEgens.

Investigation of Mannich reaction during co-liquefaction of microalgae and sweet potato waste: Combustion performance of bio-oil and bio-char.

Microalgae (MA) was co-liquefied with sweet potato waste (SPW) to improve bio-oil and bio-char qualities via Mannich reaction. The influence of Mannich reaction on combustion performances of bio-oil and bio-char were investigated. Results suggested that the addition of SPW decrease the ignition temperature of bio-oil from 186.6 °C to 165.0 °C. In addition, the denitrification effect of Mannich reaction can decrease the HCN and NO emission of bio-oil, contributing to reducing pollutant emission. As for bio-char, Mannich reaction improved the combustible material content in bio-char, which decreased the risk of slagging problem. The comprehensive combustion indexes of bio-oil (1.23 × 10-6 × min-2×°C-3) and bio-char (4.79 × 10-8 × min-2×°C-3) from co-liquefaction were higher than those from liquefaction of MA (0.91 × 10-6 × min-2×°C-3 for bio-oil and 1.24 × 10-8 × min-2×°C-3 for bio-char), indicating that the combustion performance was promoted by adding SPW. Overall, Mannich reaction can be applied to improve the combustion performance of bio-oil and bio-char.

Hydrothermal liquefaction of Chlorella pyrenoidosa and effect of emulsification on upgrading the bio-oil.

This work studied the hydrothermal liquefaction of Chlorella pyrenoidosa and effect of emulsification on upgrading the bio-oil. The fuel properties and storage stability characteristics of emulsion fuels were explored. The combustion characteristic analysis showed that the ignition temperatures of emulsion fuels (139.6-151.3 °C) were lower than that of bio-oil (176.9 °C). Besides, emulsion fuels had higher comprehensive combustion indexes (7.24-14.08 × 10-6 × min-2 × C-3) than bio-oil (1.51 × 10-6 × min-2 × C-3), indicating that emulsion fuels had better combustion performance. The kinetic analysis showed that emulsification could effectively reduce the activation energy, resulting in less energy input for combustion. Based on chemical composition evolution during the storage process, a possible stability mechanism was proposed. The storage stability analysis indicated that the diesel-solvable fractions in bio-oil had better stability. Overall, this work provides a feasible way for bio-oil upgrading through emulsification. In addition, a better understanding of the stability property of emulsion fuel was provided.

Comparison of catalytic effect on upgrading bio-oil derived from co-pyrolysis of water hyacinth and scrap tire over multilamellar MFI nanosheets and HZSM-5.

Catalytic co-pyrolysis of water hyacinth and scrap tire experiments were performed to evaluate the feasibility of improving the monocyclic aromatic hydrocarbons production. The production of monocyclic aromatic hydrocarbons increased from 5.31% (sole pyrolysis of water hyacinth) to 13.11% (co-pyrolysis with scrap tire). With use of zeolites, the highest production of monocyclic aromatic hydrocarbons can reach up to 69.18%. Comprehensive comparison on catalytic effects of HZSM-5 and multilamellar MFI nanosheets were provided. With the material to multilamellar MFI nanosheets ratios changes from 2:1 to 1:4, the production of monocyclic aromatic hydrocarbons increases significantly from 37.15-69.18%. The average production of monocyclic aromatic hydrocarbons produced by using multilamellar MFI nanosheets were 12.07% higher than that using HZSM-5, indicating the better performance of multilamellar MFI nanosheets in producing monocyclic aromatic hydrocarbons. This work provided a reference for the reuse of water hyacinth and scrap tire over multilamellar MFI nanosheets in energy field.

A luminescent cellulose ether with a regenerated crystal form obtained in tetra(n-butyl)ammonium hydroxide/dimethyl sulfoxide.

Cellulose-based luminescent materials are usually formed via either covalent attachment or combination with luminogens. In this work, three luminescent cellulose ethers without conventional luminophores have been homogeneously synthesized in a mixed solvent of tetra(n-butyl)ammonium hydroxide (TBAH)/dimethyl sulfoxide (DMSO). The one obtained by etherifying microcrystalline cellulose (MCC) with 4-bromomethylbenzoic acid (BBA), i.e., MCC-BBA, exhibits a regenerated crystal form of IVII, whereas the other two are amorphous. The large difference of crystalline properties might be due to the formation of a new hydrogen bond network in MCC-BBA derived from the intermolecular interactions of COOH and their adjacent C2/C3OH groups. Such structural deviations might result in luminescence variations. Indeed, MCC-BBA can give brighter luminescence, which might be derived from crystallization-induced luminescence as well as photo-induced charge transfer effect. The presented work provides new insights into the rational synthesis of cellulose ethers, paving the way toward the design of non-conventional cellulose-based luminescent materials.

Co-hydrothermal carbonization of polyvinyl chloride and corncob for clean solid fuel production.

The improvement of dechlorination efficiency remains an important challenge during co-hydrothermal carbonization (co-HTC) of polyvinyl chloride (PVC). In this work, co-HTC of biomass and PVC at different mixing ratios (30%-70%) and feed-water pH (3-11) was proposed to further improve the dechlorination efficiency. In terms of water solvent, the dechlorination efficiency of co-HTC process (87.83%-93.63%) was higher than that of individual HTC of polyvinyl chloride (87.44%). In case of organic acid/alkali solvents, the dechlorination efficiency further increased to 95.20% at pH = 5. Particularly, the hydrochars derived from co-HTC showed high fuel ratio (0.71-0.99) and their higher heating value reached approximately 29.16-32.83 MJ/kg. The TGA results showed that the combustion behaviors of hydrochars derived from co-HTC got better compared with that of hydrochar derived from PVC. Therefore, co-HTC can realize sustainable utilization of PVC towards clean solid fuels. This work also sheds light on the potential of organic acid in dechlorination treatment.

A study on catalytic co-pyrolysis of kitchen waste with tire waste over ZSM-5 using TG-FTIR and Py-GC/MS.

Co-pyrolysis characteristics of kitchen waste (KW) with tire waste (TW) were studied by TGA-FTIR and Py-GC/MS. The kinetic parameters were calculated by Ozawa-Flynn-Wall (OFW) and the Kissinger-Akahira-Sunose (KAS) methods. TGA-FTIR results indicated that CO2, CO, NO, NH3, SO2, CH and CC groups were the main gases released from the pyrolysis process, finding that a certain coupling synergistic interaction occurred between KW and TW. Co-pyrolysis of KW and TW displayed positive synergy in pyrolysis kinetics, especially at the ratio of 5:5 whose apparent activation energy declined 16.78% (by FWO) and 17.54% (by KAS). The Py-GC/MS results found that co-pyrolysis could increase the total peak area of volatile matters (10.92-15.34%). Moreover, co-pyrolysis could increase hydrocarbons (especially for olefins (13.25-37.42%)) and inhibit non-hydrocarbon compounds (about 63%) of volatile products. In brief, co-pyrolysis of KW and TW could be a potential way for improving quality of pyrolysis oil.