International Biodeterioration & Biodegradation最新文献

In this study, the composite activator was introduced to enhance the biodegradation of recalcitrant anthraquinone dyestuff (reactive blue 19, RB19) by Burkholderia sp. DDMZ1-1. The strain was found to decolorize 100 mg/L RB19 maximally (78% for 48 h cultivation) at the optimal conditions: static incubation, pH 6, 37 °C and 1% NaCl concentration. Further, the upgraded composite activator comprised of epigallocatechin gallate (2.5 mg/L), theanine (2.5 mg/L) and FeCl₃ (4.5 mg/L) manifested its favorable facilitative potential. An intensified secretion and activities of extracellular ligninolytic enzymes (MnP and LiP) took place via the induction of composite activator. Also, the composite activator somewhat reduced the phytotoxicity level of RB19 degraded metabolites. Proteomic profiling revealed that multiple functional proteins including pyruvate dehydrogenase, NADH-quinone oxidoreductase, superoxide dismutase, glutathione S-transferase, peroxidase, etc., were induced to be up-regulated in carbohydrate metabolism, oxidative phosphorylation, antioxidant system, glutathione metabolism and extracellular complexation with siderophores on account of composite activator. Elevated reducing force (NADH, H⁺), extracellular peroxidases (MnP, LiP, DyP) in concert with H₂O₂, and the cellular homeostasis maintenance jointly facilitated RB19 decomposition. Collectively, this study will give insights into the underlying bioaugmentation mechanism of composite activator reinforcing the bioremediation of refractory textile wastewater by an indigenous Burkholderia strain.

Using labelled-free proteomics, this study elucidates that the Enterobacter cloacae ECsp1 strain's response to tetrabromobisphenol A (TBBPA) exposure, revealing the degradation of the compound via cometabolism, which remodels the bacterial proteome. TBBPA is the dominant brominated flame retardant worldwide, but its degradation in wastewater plants remains poorly understood. Among the 531 identified proteins, 43 were up-regulated and 23 were down-regulated. Overexpressed proteins indicate that exposing this microorganism to the toxicant involves both up- and downregulation of enzymes involved in carbohydrate metabolism, genetic information processing, biosynthesis, cell maintenance, and xenobiotic degradation pathways. Evaluating the variation in protein abundance suggests degradation pathways related to: 1) the final steps of the glycolysis and alcohol fermentation in a cometabolism with glucose by phosphoglycerate mutase (PPM) and alcohol dehydrogenase (ADH) and 2) cleavage of the aromatic ring by carboxymuconolactone decarboxylase (CMD), specifically targeting benzoate and phenolic groups. The group of enzymes showing the widest variety of significantly upregulated proteins is related to xenobiotic transport elements (ABC transporters). Additionally, oxidative stress and envelope stress response are suggested by the upregulation of peroxidases and NlpE enzymes. Understanding dynamic changes in the protein expression sheds light on the metabolic mechanisms underlying TBBPA degradation during acidogenesis.

Gut microbes of Tenebrio molitor larvae are crucial in plastic degradation. However, microbial responses to the plastic feeding remains unclear. This study aimed to analyze the changes of microbial community and function feeding PE and PS. It found that after 72 h, the larvae survival rate was 92.2% and 82.2% and the plastic weight loss (consumption rate) was 8.8% (0.44 g, p < 0.01) and 6.9% (0.09 g) for PS and PE, respectively. More interestingly, plastic structure changes and the relative microbial responses happened after 6 h. CO and C–O stretching, hydrogen bonding, and a significant decrease in [M_n] (p < 0.05) and [M_W] (p < 0.001) were found; Furthermore, the time-similar microbial diversity obviously clustered and the composition significantly changed. The dominant phylum were Firmicutes and Proteobacteria. At genus level, the dominant PS-degrading taxa were unclassified Enterobacteriaceae, Acinetobacter and Sediminibacterium, and were unclassified Enterobacteriaceae, Acinetobacter and Delftia in PE samples; Additionally, difference of carbohydrate metabolism was found, and plastic degrading gene S-formyl glutathione hydrolase significantly high-expressed (PS-3500 fold and PE-5 fold); Moreover, PS-degrading pathways, such as styrene, benzoate, ethylbenzene and xylene degradation pathways were identified. Those illustrated the plastic degrading occurred just within 6 h and the plastic chemistry determined its’ degradability.

Spent mushroom substrate (SMS) from Pleurotus ostreatus is high in salinity, susceptible to deterioration caused by mold, and not suitable for direct application in soil. Its high C/N ratio and low pH inhibit the humification process during composting. Pig manure (PM) possesses high density and low porosity, impeding microbial metabolism. Co-composting SMS and PM can overcome these challenges. A 120-day composting experiment was conducted with varying mass ratios of SMS and PM, supplemented with calcium bentonite and microbial inoculum. After composting, there was observed a significant rise in the N and K₂O contents, ranging from 11.1% to 84.1% and 55.1%–296.8%, respectively. Additionally, there was a decrease in the C/N ratio by a range of 18.9%–60.1%. The total nutrient content of SMS post-composting solely was a mere 4.9%, failing to meet the 5% required by China's Professional Standard outlined for organic fertilizers (NY/T525-2021). Composting PM alone simplified the molecular structure of humic-extracted acid (HE) and reduced the C content of humic acid (HA) by up to 18.1%. In contrast, co-composting SMS and PM in equal proportions stimulated microbial consumption of water-soluble substances, resulting in increase in C contents of HE and HA by 11.5% and 18.7%, respectively, along with a 15.4% rise in the polymerization level of the composted materials. Furthermore, this combination facilitated the conversion of inert humic component, reducing C content of humin by 79.3%, lowering the electrical conductivity (EC) value by 23.0%, and boosting GI value by 154.1%. Increasing the proportion of SMS in co-compost proved advantageous in enriching its organic matter content. The composting process involved bio-degradation of O-containing functional groups like phenols and alcohols, utilization of polysaccharides by microorganisms, and development of carboxyl groups in the HA. Based on the above index analysis, the most effective compost ratio to achieve higher humification level and compost quality was determined to be a mass ratio of SMS to PM of 5:5, followed by 6:4.

Cadmium (Cd), a widely distributed and highly toxic heavy metal, poses a severe threat to soil fertility and plant growth. Citric acid (CA), a small organic acid molecule, plays a crucial role in alleviating heavy metal toxicity in plants. However, the specific mechanism underlying how CA organizes and mitigates the damage caused by heavy metals to plant cells remains unclear. Therefore, we studied the impact of exogenous CA on Cd-induced stress in Iris tectorum. The results showed that the addition of exogenous CA significantly increased the activity of antioxidant enzymes and altered the content of mineral elements including Fe, Zn, Ca, and Mn. Notably, compared to the Cd-only treatment, the proportion of Cd in the root cell walls increased by 14% in the presence of CA, and this increase was due to the ability of CA to regulate the amount of polysaccharide components in the root cell walls. CA affected the activity of pectinesterase (PME), changed the degree of pectinesterification (PMD), and enhanced the root cell walls’ ability to bind Cd, thereby reducing the Cd content in the above-ground tissues and alleviating heavy metal toxicity in plants. In summary, this study provides robust evidence that supports the use of CA to improve the efficiency of urban soil remediation.

The primary motivation of this study is the lack of knowledge regarding the shift in microbial community and functional compositions in lignocellulosic waste-based composting and vermicomposting systems. To date, the next-generation sequencing approaches have scantily been made for the isolation of plant-growth-promoting microorganisms from vermicomposting systems. Therefore, two types of lignocellulosic waste (paddy straw and food waste) are mixed with and without cow dung in different ratios and vermicomposted with Eisenia fetida, while using a series of aerobic composting as a control. Significant decreases in pH, organic C (∼3 fold), and XRD-derived crystallinity are seen most evidently in the paddy straw-food waste (1:1) mixtures upon vermicomposting (compared to composting) along with a concurrent increment of nutrients (NPK) (∼2–3.5 fold). Significant augmentation (P < 0.01) in microbial activity (biomass and respiration) and growth (bacteria and fungus) is observed under vermicomposting. A considerable shift in taxonomic diversity, accompanied by differential functional diversity of the microbial communities, is detected between paddy straw-food waste (1:1) vermicompost and compost after 60 days of incubation. The overall gene volume is greater in the vermibed than in the compost, and genes of a few well-known microbial communities with good plant growth promoting traits (e.g., Beijerinckiaceae and Propionibacteriaceae) are exclusive to the vermicompost. Additionally, genes associated with beneficial microbial activities, such as amino acid transport, nuclear structure development, and lipid transport, are found to be more abundant in vermicompost than in compost. These data are helpful in identifying suitable feedstock for isolating scalable microbial species with beneficial traits. Subsequently, six multi-dimensional plant-growth-promoting endophytic bacterial species are isolated from both the vermibed and earthworm guts. Interestingly, close genetic resemblances are found for a few of these isolates with the metagenomically detected genes. In conclusion, this is the first study to identify the practical utility of next-generation sequencing-based metagenomic analyses for the meaningful isolation of economically viable microbial species from vermicomposting systems that might replace a sizeable portion of the chemical fertilizers used in agriculture.

In lignocellulosic biomass, reducing structural recalcitrance and enhancing hydrolysis efficiency are crucial factors for increasing fermentable sugars and the production of valuable products. This biomass substrate comprises lignin, hemicellulose, and cellulose. In this study, response surface methodology was employed to optimise alkaline pre-treatment followed by enzymatic hydrolysis, aiming to enhance the saccharification of Pistia stratiotes. The NaOH concentration during pre-treatment significantly influenced the delignification process, resulting in increased cellulose content. The highest cellulose content was achieved with 2.47% NaOH at 120 °C for 60 min, leading to enhanced cell porosity and facilitating greater enzyme saccharification accessibility. Under these optimized conditions, the sample exhibited a 51.66% cellulose content. The physicochemical characteristics of the cellulose obtained after pre-treatment were analysed using SEM, FTIR, and TGA. After enzymatic hydrolysis of the cellulose with a commercially available cellulase enzyme, 31.06 g/L of reduced sugar was produced after 72 h. This study demonstrates that alkaline pre-treatment of Pistia stratiotes significantly increased its cellulose content, leading to a higher sugar yield during enzymatic hydrolysis.

Biofouling in aquaculture cages is a potential problem and its management become major concern to the planners and farmers. The study aimed to modify the surface of polyethylene aquaculture cage nets using organo silane and to evaluate the effectiveness of a nano CuO:TiO2-carbon dot biocide treatment in inhibiting marine biofouling through photocatalytic action. Polyethylene aquaculture cage net surface modified using organo silane and the surface embedded with biocide of nano CuO:TiO₂ and carbon dot (CD) derived from fish eye. The biocide-treated surface was characterized using UV–Visible and Fourier Transform Infrared spectrometry. The organo silane interacts with polyethylene via hydrogen bonding, CuO:TiO₂ interacts with the silane's Si, and the carbon dots' conjugated CC bonds interact with the transition metal and silane through van der Waals electrostatic forces and hydrogen bonding. Varied concentrations of CuO:TiO₂ and CD was coated sequentially over silane surface modified polyethylene, exposed in the marine environment to evaluate biofouling inhibition efficiency and found 0.05% each of CuO:TiO₂ and CD was optimum. The CuO:TiO₂–CD coated polyethylene cage net tested for its biofouling inhibition for 8 months in marine environment and exhibited excellent biofouling inhibition. The inhibition of biofouling was attributed to the enhanced photocatalytic action, resulting from increased electron-hole recombination, thus generating ROS, O₂٠, and OH٠ radicals. This led to the highest electronic activity around the cage net and also the formation of an acidic environment deterred microorganisms. The study highlighted the use of organo silane for surface modification of polyalkenes to load the biocide and also CuO:TiO₂–CD is a potential biocide for biofouling inhibition in aquaculture cages.

The historic libraries of Austria are often elegant classical spaces. The collections are sensitive to damage by insects, such as silverfish (Lepismatidae), biscuit beetles (Stegobium paniceum), spider beetle (Ptinus fur) and the furniture beetle (Anobium punctatum) and a range of other beetles e.g. Dermestidae, which attack carpets and museum objects. Warmer conditions and changes in humidity might encourage new species to appear at these locations. Historic libraries represent a useful group to study, because they have similar collections, with only limited addition of new material and sometimes very few visitors, thus representing a stable indoor ecosystem. The five monastic libraries in the study occupy a range of settings, from rural to urban. Additionally, there were three research libraries in Vienna. Insects were caught over several years (up to 10) from the eastern parts of Austria using sticky blunder and pheromone (webbing clothes moth) traps. Higher annual catch rates were found in more rural monastic settings and revealed a less even spread of species (a high Gini coefficient) than at urban sites. The Shannon diversity was higher in the urban research libraries. Species within the same family can show differences in preference: silverfish Lepisma saccharinum (rural), Ctenolepisma longicaudatum (urban) or C. calvum (urban), carpet beetles Anthrenus museorum (rural) and A. verbasci (urban). The differences may be a function of the land use, climate, air pollution or human activities. The work suggests that managing insects in these libraries need to account for differences between rural and urban locations.

Arsenic (As) pollution in croplands is a significant global environmental issue. Being the dominant irrigated crop, rice is the main focus for research related to arsenic toxicity, however, wheat being the basic staple food has not been studied well. Therefore, the present study sought to investigate the potential of arsenic-tolerant rhizobacteria for its mitigation in wheat. Ten As tolerant bacterial strains were characterized for abiotic stress tolerance, antibiotic resistance, and plant growth-promoting traits. Methyltransferase containing Pseudomonas oleovorans (NBRI-B4.10) with a better arsenic tolerance index (151.74%) in wheat outperformed the other strains. In vitro study, showed the highest phosphate solubilization ability (40.17 μgmL⁻¹) under As⁺⁵ (250 μgmL⁻¹) stressed condition in NBRI-P media, accompanied with more As biosorption (72.9%) in culture pellet, confers the As detoxification ability of B4.10 during arsenic-phosphate (As–P) interaction too. Organic acid production studied during the process of P-solubilization by methyltransferase bacteria, NBRI-B4.10 reveals the production of higher concentrations of gluconic and tartaric acid at As⁺⁵ (25 μgmL⁻¹) stress. Furthermore, NBRI-B4.10 inoculation increased the plant growth and nutrient content (Se) while decreasing As content in grain (∼53.3%) leading to arsenic abatement in wheat.