International Biodeterioration & Biodegradation最新文献

A strain of Bacillus licheniformis T5 was isolated from soil contaminated with crude oil due to its efficient degradation of polycyclic aromatic hydrocarbons (PAHs). When subjected to stress metabolism using phenanthrene as a carbon source, significant changes were observed in T5 cells. Infrared spectrum analysis revealed the presence of -C=C- and Ph-O-C (aromatic) groups on the bacterial surface, facilitating the adsorption of PAHs on the phospholipid layer and causing damage to the cell membrane. Scanning electron microscope (SEM) analysis showed the changes of cell morphology, including a large number of folds on the lower surface and the folding of cell membrane. Transmission electron microscope (TEM) observation showed that non-stressed bacteria with adequate nutritional conditions accumulated more lipids. However, the stress group contained more protein. It was found that stress metabolism led to the increase of protein content in T5 cells by 16.4% and the activity of oxidoreductase more than doubled. These physiological and biochemical changes enhance the ability of stressed bacteria to degrade PAHs efficiently, thereby reducing the degradation cycle. The findings offer valuable insights for the remediation of PAHs pollution.

Acitretin is a primary treatment for moderate-to-severe psoriasis, however, the substantial side effects associated with its daily oral administration and relapse after withdrawal significantly restrict its clinical utility. To address this challenge, we designed a transdermal delivery system using hyaluronic acid-based dissolving microneedle patches containing poly (lactic-co-glycolic)-encapsulated acitretin nanoparticles for effective topical drug administration and prolonged therapeutic effects. This microneedle exhibited favorable mechanical properties, which could easily penetrate through the thickened epidermis for intralesional drug delivery. We showed that numbers of acitretin-loaded microspheres were uniformly compacted at the bottom of needle tips, giving the microneedle dense surface morphology required for effective skin penetration, prolonged retention, and sustained release of acitretin both in vitro and in an imiquimod-induced psoriasis in vivo model. A single dose of our transdermal treatment not only alleviated the psoriasis-like skin inflammation in acute phase, but also established a long-term therapeutic effect. Moreover, the transdermal approach proved more effective than daily oral administration of the same dose of free drug, demonstrating less systemic toxicity than oral drug intake or topical cortisol application. This new system offers an innovative way for drug delivery and disease treatment, and also provides an antimicrobial control strategy for a wide range of applications.

Bisphenol A (BPA) is the most extensively produced chemical in the world. With its growing demand, it has become a common emerging organic contaminant (EOC) in the environment. It is an endocrine-disrupting chemical (EDC) that can disrupt the endocrine system and induce negative impacts on human health and other biota. To detoxify or remove BPA from the contaminated environment, researchers have developed several physicochemical and biological methods. Biodegradation is usually considered economical and environmentally safe. In the last few decades, huge experiments have been conducted using bacteria and fungi to degrade BPA. Thus, the present review aims to better understand the current knowledge on BPA biodegradation with bacteria and fungi to discover the limitations of those studies. In the case of bacteria, researchers used direct environmental raw samples for enrichment, isolation and degradation. Pseudomonas sp. was the most common bacteria in those samples to degrade BPA. Whereas in the case of fungi, previously isolated pure fungal strains were used. Those fungi were either ascomycetes or basidiomycetes, and most of those fungi produced an extracellular enzyme, laccase, to degrade BPA. Literature review shows that two toxic metabolites for fungal-mediated degradation (p-isopropenyl phenol and 4-ethyl−2-methoxyphenol) and six toxic metabolites for bacterial-mediated degradation (p-hydroxybenzoic acid, p-hydroxybenzaldeyde, p-hydroxyacetophenone, hydroquinone, 2,3-bis(4-hydroxyphenyl)-1,2-propanediol, and p-hydroxyphenacylalcohol) were produced. Our review also reveals that most previous studies were conducted under non-extreme conditions, though extreme environments can be contaminated with BPA. Therefore, this review is certainly helpful in deeply revising the existing knowledge on BPA biodegradation to conduct novel research in the future to fill the research gaps in safer ways.

A significant quantity of microplastics (MPs) is concealed within biological sludge. Current research predominantly examines the effects of non-biodegradable MPs on traditional sludge. However, the influence of biodegradable MPs on the functional microbial activity of anaerobic ammonium oxidation granular sludge (AnGS) remains inadequately explored. This study specifically investigated the effects of non-biodegradable polypropylene (PP) MPs and biodegradable polylactic acid (PLA) MPs on AnGS under short-term stress. The study found that PP MPs inhibited nitrogen removal performance, reducing nitrogen removal efficiency by 1.14% (100 mesh) and 5.77% (1000 mesh) respectively, along with decreased hydrazine dehydrogenase (HDH) activity. Conversely, PLA promoted denitrification performance, increasing efficiency by 8.21% (100 mesh) and 6.54% (1000 mesh). In response to MPs-induced environmental stress, the secretion of extracellular polymeric substances (EPS) increased in all experimental groups. Additionally, non-targeted metabolomic analysis revealed a decrease in the abundance of KEGG pathways related to carbon and amino acid metabolism in the experimental groups, while the enrichment of terephthalate and benzamide in the PLA groups significantly impacted its process. These findings offered valuable insights into the impact of MPs on anaerobic ammonium oxidation (anammox) and could potentially enhance its application.

Bioremediation has garnered considerable interest due to its advantages of economy and no secondary pollution. However, the direct electron transfer rate between microorganisms and Cr(VI) is low. The bioreduction of Cr(VI) by Shewanella oneidensis MR-1 (S. oneidensis) in the presence of formylmethylflavin (FMF) was conducted to understand how FMF mediated the extracellular electron transfer process to improve Cr(VI) removal. In this study, FMF was firstly synthesized by modifing RF to increase its solubility and redox activity. The findings indicate that S. oneidensis/FMF exhibited better Cr(VI) removal performance compared to that of S. oneidensis. Under optimum conditions, 40 mg/L Cr(VI) could be completely removed by S. oneidensis/FMF within 120 h, while only 48.6% of Cr(VI) was removed by S. oneidensis, and the first order rate constant (k) for the Cr(VI) elimination by S. oneidensis/FMF (0.033 h⁻¹) was about 4.1-fold greater than that of S. oneidensis (0.008 h⁻¹). Moreover, the removal of Cr(VI) by S. oneidensis/FMF were dominated by reduction, and supplemented by adsorption and complexation. FMF enhance the extracellular electron transfer rate (EETR) was confirmed by electrochemical cyclic voltammetry (CV) and linear scanning voltammetry (LSV) experiments. This study emphasizes the potential important role of FMF in environmental bioremediation.

The degradation of cellulose-based materials by fungi represents a menace to the cultural heritage conservation. Carvacrol-based β-cyclodextrins and cocrystals proved effective antifungal remedies in vitro but their effects on paper structure and properties were not studied. The aim of this study was to investigate possible structural modifications and alterations of the mechanical, optical and chemical properties of artificially aged and unaged Whatman and Kraft paper subjected to the treatment with carvacrol-based β-ciclodextrins and cocrystals. The pH of the samples did not significantly change after the treatment, as well as no colour-related alterations were detected (1.00<ΔE<2.00). The tensile strength of both Whatman and Kraft paper was not affected by the vapours of carvacrol and spectroscopic analysis (FTIR and XRD) revealed no carvacrol-related damages of paper structure. The antifungal efficacy of the carvacrol-cocrystal was also proved on a book prototype made of Whatman and Kraft paper, kept under 98% of humidity for 28 days, and purposely inoculated with a mix of fungal species (A. alternata, Aspergillus sp. section Nigri, C. cladosporioides, and T. orientale). These results show the applicability of a carvacrol-releasing system, effective as antifungal remedy, and at the same time not harmful to Whatman and Kraft paper, as these materials did not show treatment-induced degradation.

The long-term exposure of cerium oxide nanoparticles (CeO₂ NPs) at 5, 20, and 50 mg/L to the biofilm and its impact on the treatment of synthetic wastewater, containing phenol, in a trickling bioreactor (TBR) were examined. An increase of 38.1 % in the reactive oxygen species (ROS) production and 29.0 % in the lactate dehydrogenase (LDH) release indicated that CeO₂ NPs were toxic to the microorganisms at 50 mg/L and disrupted the integrity of the microbial membrane within the community. Phenol biodegradation, total nitrogen (TN), and total phosphorus (TP) removal slightly changed from 98.6, 53.7, and 13.0 % in the absence of NPs to respectively 96.5, 49.7, and 9.0 % in the presence of 50 mg/L CeO₂ NPs. High-throughput sequencing after prolonged 30-day exposure to CeO₂ NPs showed that the microbial community could self-regulate the population by adjusting species composition in response to the presence of NPs. The relative abundance of some sensitive species such as Castellaniella defragrans declined from 39.5 to 0.6 % in the presence of NPs. However, other species such as Comamonadaceae bacterium thrived and became more prevalent. The TBR effectively removed phenol, TN, and TP in the presence of CeO₂ NPs, benefiting from the cells immobilization that limited the access of NPs to the deep layers of biofilm.

Due to its higher biochemical oxygen demand (BOD) and chemical oxygen demand (COD), the rice mill industry is considered a major polluting sector. The issue is becoming more serious due to the organic portions of the rice mill effluent, such as starch and other biodegradable constituents. The main objective of this review is to discuss the most commonly used methodologies (physico-chemical, phytoremediation, and biological) for treating rice mill effluent and highlight their effectiveness, with a greater emphasis on biological techniques. The study also included discussions on rice milling operations and the current status of rice mill effluent generation. The physico-chemical techniques effectively reduce BOD, COD, total suspended solids (TSS), and total dissolved solids (TDS) from the effluents. Still, it has limitations, such as the utilization of high-cost reagents and the requirement for external energy. Researchers have recognized biological techniques as the most economical choice for treating industrial effluents containing organic constituents. Phytoremediation ensures better aesthetics and a healthier environment while assisting industries to minimize toxic compounds and nutrients. The review also looked at the methodology, advantages, and limitations of the treatment technologies used in rice mill wastewater treatment. Furthermore, we update all of these treatment techniques with relevant data from the literature. At the end of the study, we include aspects related to the conclusions and future scope of the topic.

The inhibition of heterotrophic nitrification-aerobic denitrification (HN-AD) process and low efficiency of total nitrogen conversion under nitrite stress were overcome by strain EN-F2. Results demonstrated that nitrite addition increased total nitrogen conversion to 91.36% and 87.02% for ammonium and nitrate systems, respectively, representing improvements of 5.61% and 15.41%. This enhancement is likely due to the simultaneous acceleration of cell growth, and consumption of ammonium and nitrate. Furthermore, 10 mg/L of hydroxylamine could be almost completely oxidized in a wide range of environmental conditions in the presence of 50 mg/L nitrite, and 100% and 89.82% of nitrite and total nitrogen could be degraded under the conditions of 25 °C, sodium succinate, 7.40 mg/L of dissolved oxygen, C/N ratio 20, initial pH 7.40–7.80 and inoculation quantity of 0.5 × 10⁸ CFU/mL. Altogether, the HN-AD performance of strain EN-F2 can be promoted by nitrite, and no nitrate and hydroxylamine accumulation were found.

Termites are significant pests in many regions of the world, where they attack cellulose-based material in buildings, trees, and crops. The most significant economic losses occur to timber in structures, and a great deal of effort and money is spent to prevent damage to homes and public buildings. Termites may attack wood anywhere in a building, from below soil to the highest point on the roof. Detection of termites is often challenging due to the cryptic nature of termites, the complexity of the structure, the location of damage or termites in the structure, and available techniques. Several methods have been employed to detect and monitor the presence of termites in buildings, from simple visual searches to technology-based or technology-assisted approaches that vary in their invasiveness and destructiveness. This review examines the various techniques used to detect drywood and subterranean termites, explains the underlying termite biology connected with each detection method, and considers the benefits and drawbacks of each technique discussed. This will hopefully help professional pest inspectors and property owners select suitable termite detection methods. This review also highlights the need for continued research to develop and evaluate detection strategies and tools that may be utilized before implementing any termite control measures.