Search

This study is to understand and analyze the development history, research hotspots, and research trends in the study of microbial diseases of cultural heritage through bibliometric analyses in order to fill the current gap of no literature review in this research field and to make certain contributions to the research in this field and the protection of cultural heritage. Bibliometric and visual analyses of the literature on cultural heritage microbial diseases in the Web of Science (WoS) core collection were carried out using VOSviewer and R-bibliometrix, choosing the two main literature types of papers and reviews. The emphasis was placed on analyzing and summarizing core research strengths, hotspots, and trends. Six hundred sixty-seven documents (573 articles and 94 reviews) were retrieved. αIn the WoS core collection, the first literature on cultural heritage microbial disease research was published in January 2000, and the annual number of publications from 2000 to 2009 did not exceed one; the annual number of publications from 2010 onwards increased rapidly, and after 2018, the number of publications per year exceeded 60, reaching 94 in 2020, which indicates that cultural heritage microbial disease research is booming. Our research showed that Italy, the USA, and China were the leading research countries, and Univ Milan was the institution with the most publications. International Biodeterioration &Biodegradation was the most published and co-cited journal, and Gu JD was the most prolific author. The research hotspots in the study of microbial diseases of cultural heritage mainly include biological degradation of cultural heritage; identification of diseased microorganisms and disease mechanisms; cultural heritage microbial disease prevention and control methods; monitoring, prevention, and control of diseased microorganisms in indoor air; antibacterial agents, especially essential oils, nanoparticles, and other safe and efficient antibacterial products research and development; and exploration of the mechanisms of biofilm protection of cultural heritage on cultural heritage surfaces. Monitoring and identifying cultural heritage microbial communities, identifying disease mechanisms, and researching safe and efficient bacteriostatic products such as essential oils and nanoparticles will be the main research directions in the field of cultural heritage microbial disease prevention and control in the future. [ABSTRACT FROM AUTHOR]

The high consumption and emission of sulfonamide antibiotics (SAs) have a considerable threat to humans and ecosystems, so there is a need to develop safer and more effective methods than conventional strategies for the optimal removal of these compounds. In this study, four SAs with different substituents, sulfadiazine (SDZ), sulfamerazine (SMR), sulfamethoxazole (SMX), and sulfamethazine (SMZ) were removed by a pure culture of Paenarthrobacter ureafaciens YL1. The effect of the initial SAs concentration on the growth rate of strain YL1 was investigated. The results showed that the strain YL1 effectively removed various SAs in the concentration range of 0.05–2.4 mmol·L−1. The Haldane model was used to perform simulations of the experimental data, and the regression coefficient of the model indicated that the model had a good predictive ability. During SAs degradation, the maximum specific growth rate of strain YL1 was ranked as SMX > SDZ > SMR > SMZ with constants of 0.311, 0.304, 0.302, and 0.285 h−1, respectively. In addition, the biodegradation of sulfamethoxazole (SMX) with a five-membered substituent was the fastest, while the six-membered substituent of SMZ was the slowest based on the parameters of the kinetic equation. Also, density functional theory (DFT) calculations such as frontier molecular orbitals (FMOs), and molecular electrostatic potential map analysis were performed. It was evidenced that different substituents in SAs can affect the molecular orbital distribution and their stability, which led to the differences in the growth rate of strain YL1 and the degradation rate of SAs. Furthermore, the toxicity of P. ureafaciens is one of the crucial factors affecting the biodegradation rate: the more toxic the substrate and the degradation product are, the slower the microorganism grows. This study provides a theoretical basis for effective bioremediation using microorganisms in SAs-contaminated environments. [ABSTRACT FROM AUTHOR]

Indole, as a typical N-heterocyclic aromatic pollutant, poses risks to living things; however, indole-biotransformation mechanisms remain under-discussed, especially those related to its downstream biotransformation. Here, we systematically investigated the characteristics of indole degradation by strain Cupriavidus sp. IDO. We found that Cupriavidus sp. IDO could utilize 25 to 150 mg/L indole within 40 h and identified three intermediates (2-oxindole, indigo, and isatin). Additionally, integrated genomics and proteomics analysis of the indole biotransformation mechanism in strain IDO revealed 317 proteins showing significant changes (262 upregulated and 55 downregulated) in the presence of indole. Among these, three clusters containing indole oxidoreductase, CoA-thioester ligase, and gentisate 1,2-oxidoreductase were identified as potentially responsible for upstream and downstream indole metabolism. Moreover, HPLC-MS and -omics analysis offered insight into the indole-degradation pathway in strain IDO. Furthermore, the indole oxidoreductase IndAB, which initiates indole degradation, was heterologously expressed in Escherichia coli BL21(DE3). Optimization by the response surface methodology resulted in a maximal production of 135.0 mg/L indigo by the recombination strains in tryptophan medium. This work enriches our understanding of the indole-biodegradation process and provides new insights into multiple indole-degradation pathways in natural environments. [ABSTRACT FROM AUTHOR]

Microcystins (MCs) are toxic compounds produced by cyanobacteria in eutrophicate water environment and threaten the drinking water quality which often leads to serious sicknesses. MCs are difficult to be removed in water treatment when the concentration is very low but still harmful. When the MC concentration is low (μg/L), filter or some conventional chemical does not work, but UV can keep removing it to a lower level by some active groups. Herein, 185-nm UV irradiation in an immersing mode was used to remove MCs. Compared with the normal radiation mode, the immersing mode showed a remarkable degradation rate of MCs and a greater removal efficiency than the direct radiation. Radicals of ·H and ·OH were produced and strengthened the removal rate, after HO absorbed 185 nm photons. Three important factors of pH value, initial concentration, and aeration capacity were investigated. When pH was less than 7, a better removal rate by ·H was found, due to the main path of MC degradation and Adda strain removal. When the initial concentration increased, the MC removal ratio decreased because HO· formed near the lamp surface and degraded MC molecules fast. When the aeration capacity improved, the MC removal ratio for the presence of air enforced reaction of dissolved oxygen with hydrated electrons and hydrogen atoms produced in the radiolysis. [ABSTRACT FROM AUTHOR]

In the present study, microcalorimetry was used to monitor the non-growth metabolism of Nitrosomonas europaea ( N. europaea) cells, which could biodegrade the micropollutant (triclosan). The presence of triclosan promote non-growth metabolism and extend the life of N. europaea cells. However, at high concentration of triclosan (4 mg L), the acute toxicity was induced in cells. The addition of allylthiourea inhibited the non-growth metabolism of N. europaea, suggesting that ammonia monooxygenase is responsible for the biodegradation of triclosan. Scanning electron microscopy result showed the cell membrane damage induced by triclosan. It is concluded that triclosan would bind to ammonia monooxygenase on the cell membrane and cause acute toxicity. Triclosan (<1.0 mg L) is favor for the non-growth metabolism, while high concentration (4.0 mg L) is toxic to N. europaea cells. [ABSTRACT FROM AUTHOR]

Abstract: The lauryl benzene sulfonic acid sodium (LAS)-carbon nanotube (CNT)-modified PbO2 electrode was fabricated by thermal deposition and electrodeposition methods. Its morphology and composition were compared with those of PbO2, CNT-PbO2, and LAS-PbO2 electrodes. It was found that CNT could be doped into the PbO2 film in the presence of LAS. The [Fe(CN)6]4−/3− redox couple in 0.1M KCl was used for initial evaluation of the electro-catalytic activity of prepared electrodes. The results showed that LAS-CNT-PbO2 electrode exhibited the largest peak current and the smallest ΔE p in [Fe(CN)6]4−/3− redox process. The stability tests showed that the service life of LAS-CNT-PbO2 electrode was 1.8 times longer than that of PbO2 electrode. The electro-catalytic activity of the prepared electrodes was also examined for the electrochemical oxidation of 4-chlorophenol (4-CP) and the LAS-CNT-PbO2 electrode exhibited the highest activity for 4-CP degradation among the four PbO2-based electrodes. Besides, HPLC was employed to identify the products resulting from the electrochemical oxidation of 4-CP and the degradation mechanism of 4-CP was also discussed. [Copyright &y& Elsevier]

To obtain novel salt-tolerant phenol-degrading bacteria and amplify the corresponding genes, a bacterium named W1 was isolated from the active sludge samples. 16S rRNA sequence analysis was used to identify the bacterium, and characteristics for phenol biodegradation were also studied. The 5' - and 3' -flanking regions of gene encoding the phenol hydroxylase were amplified from strain W1 by TAIL-PCR method. 1 wt % -10 wt % was showed that strain W1 was identified as Arthrobacter sp. The strain was capable of growing in the medium with 1 wt % -10wt% NaCl and utilizing phenol as the sole carbon and energy source. And it could also degrade some other aromatic compounds such as p -methylphenol, salicylic acid and p -hydroquinone, etc. When concentration of NaCl was about 5 wt %, 1 000 mg · L-1 phenol could be degraded more than 90% by strain W1. The complete gene cluster was about 6 kb, of which the gene encoding the large subunit of phenol hydroxylase exhibited the highest similarity about 93% with the corresponding gene of Alcaligenes sp. [ABSTRACT FROM AUTHOR]

Biodegradation of 1,4-dioxane (dioxane) contamination has gained much attention for decades. In our previous work, we isolated a highly efficient dioxane degrader, Xanthobacter sp. YN2, but the underlying mechanisms of its extraordinary degradation performance remained unresolved. In this study, we performed a comparative transcriptome analysis of YN2 grown on dioxane and citrate to elucidate its genetic degradation mechanism and investigated the transcriptomes of different dioxane degradation stages (T0, T24, T48). We also analyzed the transcriptional response of YN2 over time during which the carbon source switched from citrate to dioxane. The results indicate that strain YN2 was a methylotroph, which provides YN2 a major advantage as a pollutant degrader. A large number of genes involved in dioxane metabolism were constitutively expressed prior to dioxane exposure. Multiple genes related to the catabolism of each intermediate were upregulated by treatment in response to dioxane. Glyoxylate metabolism was essential during dioxane degradation by YN2, and the key intermediate glyoxylate was metabolized through three routes: glyoxylate carboligase pathway, malate synthase pathway, and anaplerotic ethylmalonyl–CoA pathway. Genes related to quorum sensing and transporters were significantly upregulated during the early stages of degradation (T0, T24) prior to dioxane depletion, while the expression of genes encoding two-component systems was significantly increased at late degradation stages (T48) when total organic carbon in the culture was exhausted. This study is the first to report the participation of genes encoding glyoxalase, as well as methylotrophic genes xoxF and mox, in dioxane metabolism. The present study reveals multiple genetic and transcriptional strategies used by YN2 to rapidly increase biomass during growth on dioxane, achieve high degradation efficiency and tolerance, and adapt to dioxane exposure quickly, which provides useful information regarding the molecular basis for efficient dioxane biodegradation. [ABSTRACT FROM AUTHOR]

The microorganism Arthrobacter. ZXY-2 exhibits excellent degradation efficiency for atrazine in free cells. However, its poor fixability makes it hard to be kept and recycled in water. To conquer the problem, this work employed mycelial pellets of Aspergillus niger Y3 to immobilize ZXY-2, which formed a self-immobilized biomixture (SIB) to remove atrazine. SIB could completely degrade 57.3 mg/L atrazine within 10 h. The SIB exhibited the highest degradation efficiency at pH = 7 and 40 °C. Degradation of atrazine with initial concentrations of 57.3 mg/L and 17.5 mg/L was described well by zero and first-order reaction kinetics, respectively. The recycling experiments demonstrated that SIB could be recycled for 5 batches. The results of SEM, FT-IR, and zeta potential analysis showed that porous structure, functional groups, and electronegativity of SIB all contributed to its stable formation. Therefore, this study demonstrates that SIB could be formed stably and could remove atrazine efficiently. Unlabelled Image • Arthrobacter. sp. ZXY-2 was encapsulated by self-immobilized Aspergillus niger Y3 in water to form SIB. • SIB removed 57.3 mg/L atrazine rapidly within 10 h. • SIB could be recycled for 5 times. [ABSTRACT FROM AUTHOR]

Mycelial pellets, as a novel biomass material, can adsorb pollutants as a biosorbent, or combine other substances and organisms to form self‐immobilized biomixture (SIB) to remove pollutants from wastewater. The pellets are eco‐friendly, have a good self‐immobilization capacity, and are easy to filter. In addition, some mycelial fungi can remove the pollutants in water through biodegradation. This study reviewed biomixture based on mycelial pellets and the two ways, through which SIB remove pollutants in water: pure pellets and the pellets with other materials. The characteristics and functions of each part of SIB were discussed. The study also highlighted the shortcomings of the technology and provided recommendations for further development of this technology. [ABSTRACT FROM AUTHOR]

Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly to keep a safe environment. In the present study, a new atrazine-degrading strain ZXY-1, identified as Pseudomonas , was isolated. This new isolated strain has a strong ability to biodegrade atrazine with a high efficiency of 9.09 mg/L/hr. Temperature, pH, inoculum size and initial atrazine concentration were examined to further optimize the degradation of atrazine, and the synthetic effect of these factors were investigated by the response surface methodology. With a high quadratic polynomial mathematical model ( R 2 = 0.9821) being obtained, the highest biodegradation efficiency of 19.03 mg/L/hr was reached compared to previous reports under the optimal conditions (30.71°C, pH 7.14, 4.23% ( V/V ) inoculum size and 157.1 mg/L initial atrazine concentration). Overall, this study provided an efficient bacterium and approach that could be potentially useful for the bioremediation of wastewater containing atrazine. [ABSTRACT FROM AUTHOR]

• Self-immobilized biomixture was prepared for degradation of atrazine. • Adsorption of biochar by pellets followed pseudo-second-order kinetic model. • Biochar improved atrazine removal ability and reusability of biomixture. • Agrobacterium sp. WL-1 significantly enhanced ATZ degradation ability of Arthrobacter sp. ZXY-2 of ATZ. • ATZ intermediate metabolite were examined. A self-immobilization method for microorganisms was developed based on fungal pellets. Generally, pellets have some problems such as cell leakage, cell loading limitation and low mechanical strength. Therefore, biochar was applied to overcome these disadvantages. Atrazine degradable microorganism Arthrobacter sp. ZXY-2 was immobilized by Aspergillus niger Y3 pellets. After adding biochar with optimal dosage (0.006 g biochar for 0.3 g pellets with ZXY-2), the self-immobilized biomixture (SIB) removed 50 mg /L atrazine rapidly within 1 h, which was 61% higher compared to pellets without biochar. The kinetic adsorption results showed that the biosorption of biochar by pellets followed a pseudo-second-order kinetic model. The ATZ removal ability and reusability of SIB were significantly increased by biochar. The results showed that the addition of biochar could enhance the connection between ZXY-2 and pellets based carrier, and the favorable biodegradation pH of ZXY-2 changed to 6 and 10. Several analyses such as ζ-potential measurements, FTIR, XPS, SEM-EDS, and elemental analyses were performed to evaluate the mechanism of action of SIB. To enhance the ATZ degradation by single strain, Agrobacterium , sp WL-1 was isolated and added. The metabolic pathways and their function complementation were studied. Furthermore, a biomass integration model for wastewater treatment was proposed herein. [ABSTRACT FROM AUTHOR]

Highlights: [•] Three polysaccharides were obtained from the degradation of Poria cocos polysaccharide (PCP) by different concentrations of H2O2. [•] Each polysaccharide was a heteropolysaccharide composed of glucose and arabinose. [•] The antioxidant activities were investigated by various established in vitro systems. [•] All the samples had a certain capacity for DNA damage protection. [•] PCP-1 had a stronger capacity for DNA interaction. [ABSTRACT FROM AUTHOR]

Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature (10°C) from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions: pH 7.0, 10°C, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. V max and K s were found to be 0.0094 hr −1 and 32.5 mg/L, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A novel meta-fission product hydrolase gene (mfphA) located in the bphX gene region of Dyella ginsengisoli LA-4 was successfully cloned and heterologously expressed in this study. The deduced amino acid sequence of MfphA showed 75% identity with the sequence of 2-hydroxymuconic semialdehyde hydrolase from Pseudomonas putida UCC22. The results suggested that MfphA belonged to the α/β hydrolase family, which could hydrolyze the meta-fission products (MFPs) during the biodegradation process of monocyclic compounds. The His-Tag MfphA was purified, and the subunit molecular mass of MfphA was about 35.3kDa by SDS-PAGE analysis. According to the apparent kinetic parameters, the specificity of MfphA was determined in the following order: 6-methyl-HODA>HODA>5-methyl-HODA>6-phenyl-HODA>5-chloro-HODA (HODA, 2-hydroxy-6-oxohexa-2,4-dienoate). The activity of MfphA for HODA was higher than that for 6-methyl-HODA. It was shown that the maximum activity was at 70°C, and MfphA was stable for storage at low temperature for 30 days. [Copyright &y& Elsevier]

Abstract: The biodegradation of polycyclic aromatic hydrocarbons (PAHs) (8.15mg PAHskg−1 soil) in aged contaminated soil by isolated microbial consortium (five fungi and three bacteria) during the incubation of 64d is reported. The applied treatments were: (1) biodegradation by adding microbial consortium in sterile soils (BM); (2) biodegradation by adding microbial consortium in non-sterile soils (BMN); and (3) biodegradation by in situ “natural” microbes in non-sterile soils (BNN). The fungi in BM and BMN soils grew rapidly 0–4d during the incubation and then reached a relative equilibrium. In contrast the fungi in BNN soil remained at a constant level for the entire time. Comparison with the fungi, the bacteria in BNN soils grew rapidly during the incubation 0–2d and then reached a relative equilibrium, and those in BM and BMN soils grew slowly during the incubation of 64d. After 64d of incubation, the PAH biodegradations were 35%, 40.7% and 41.3% in BNN, BMN and BM, respectively. The significant release of sequestrated PAHs in aged contaminated soil was observed in this experiment, especially in the BM soil. Therefore, although bioaugmentation of introduced microbial consortium increased significantly the biodegradation of PAHs in aged contaminated soil with low PAH concentration, the creation of optimum of the environmental situation might be the best way to use bioremediation successfully in the field. [Copyright &y& Elsevier]

Chelatococcus sp. CO-6 is a crude-oil-degrading strain, which was isolated from Shengli Oilfield. However, little genetic information is known about this species. We present the complete genome sequence analysis of Chelatococcus sp. CO-6 in this study. It could provide further insight into its genetic basis for membrane transport and immune system against bacteriophage in strain CO-6. [ABSTRACT FROM AUTHOR]