Exploring biodegradative efficiency: a systematic review on the main microplastic-degrading bacteria.

Introduction: Microplastics (MPs) are widely distributed in the environment, causing damage to biota and human health. Due to their physicochemical characteristics, they become resistant particles to environmental degradation, leading to their accumulation in large quantities in the terrestrial ecosystem. Thus, there is an urgent need for measures to mitigate such pollution, with biological degradation being a viable alternative, where bacteria play a crucial role, demonstrating high efficiency in degrading various types of MPs. Therefore, the study aimed to identify bacteria with the potential for MP biodegradation and the enzymes produced during the process. Methods: The methodology used followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Results and Discussion: The research yielded 68 eligible studies, highlighting bacteria from the genera Bacillus, Pseudomonas, Stenotrophomonas, and Rhodococcus as the main organisms involved in MP biodegradation. Additionally, enzymes such as hydrolases and alkane hydroxylases were emphasized for their involvement in this process. Thus, the potential of bacterial biodegradation is emphasized as a promising pathway to mitigate the environmental impact of MPs, highlighting the relevance of identifying bacteria with biotechnological potential for large-scale applications in reducing MP pollution.

Valorization of sugarcane bagasse for high-yield production of laccase through Aspergillus terreus for effective azo dye decolourization.

Synthetic dyes such as azo dyes are significant pollutants in the wastewater released from various textile industries. The low biodegradability and production from synthetic sources with high shelf life make azo dyes a challenging material for degradation. This study used chemically mutated Aspergillus terrus in the laccase production under solid-state fermentation using sugarcane bagasse. Initially, the wild-type strain produced a laccase activity of 4.12 U/mL. Later, the alkaline pretreatment of sugarcane bagasse showed a significant increase in laccase activity by 38.9%. Further, random mutagenesis treatment with 100 mM EMS generated a hyper laccase-producing strain with a 2.3-fold increment in laccase activity compared to the wild-type strain. The enzyme displayed optimal activity at pH 6.5 and 35 °C. The metal ions such as Fe3+ (29.4 U/mL), Fe2+ (20.8 U/mL) and Cu2+ (18.05 U/mL) showed positive effects on laccase activity. The crude laccase was used to bioremediate Congo red, a prominent azo dye used in textile and pharmaceutical industries. The preliminary studies with a crude enzyme displayed 68.86% dye decolourization after 24 h of incubation. Additionally, with Taguchi orthogonal array optimization experiments, the maximal dye decolorization of 78.24% was achieved by maintaining crude enzyme concentration (20 U), dye concentration (25 mg/L) and pH 4.5.

Improved, reference quality genome sequence of the plastic-degrading greater wax moth, Galleria mellonella.

Galleria mellonella is a pest of honeybees in many countries because its larvae feed on beeswax. However, G. mellonella larvae can also eat various plastics, including polyethylene, polystyrene and polypropylene, so the species is garnering increasing interest as a tool for plastic biodegradation research. This paper presents an improved genome (99.3% completed lepidoptera_odb10 BUSCO; genome mode) for G. mellonella. This 472 Mb genome is in 221 contigs with an N50 of 6.4 MB and contains 13,604 protein-coding genes. Genes that code for known and putative polyethylene-degrading enzymes and their similarity to proteins found in other Lepidoptera are highlighted. An analysis of secretory proteins more likely to be involved in the plastic catabolic process has also been carried out.

Characterization and removal mechanism of fluoroquinolone-bioremediation by fungus Cladosporium cladosporioides 11 isolated from aquacultural sediments.

Antibiotics have been widely detected in aquatic environments, and fungal biotransformation receives considerable attention for antibiotic bioremediation. Here, a fungus designated Cladosporium cladosporioides 11 (CC11) with effective capacity to biotransform fluoroquinolones was isolated from aquaculture pond sediments. Enrofloxacin (ENR), ciprofloxacin (CIP) and ofloxacin (OFL) were considerably abated by CC11, and the antibacterial activities of the fluoroquinolones reduced significantly after CC11 treatment. Transcriptome analysis showed the removal of ENR, CIP and OFL by CC11 is a process of enzymatic degradation and biosorption which consists well with ligninolytic enzyme activities and sorption experiments under the same conditions. Additionally, CC11 significantly removed ENR in zebrafish culture water and reduced the residue of ENR in zebrafish. All these results evidenced the potential of CC11 as a novel environmentally friendly process for the removal of fluoroquinolones from aqueous systems and reduce fluoroquinolone residues in aquatic organisms.

Biogeochemical modelling to assess the effect of bioclogging on multiple electron acceptor-mediated petroleum hydrocarbon bioremediation in vadose zone.

Bioremediation is an economically viable and sustainable clean-up strategy. Hydrodynamic, as well as transport characteristics of the porous medium, can evolve over the period as a result of biological clean-up activities. The present study proposes a 2-D numerical framework to simulate the effect of bioclogging on multiple electron acceptor-mediated petroleum hydrocarbon bioremediation in the vadose zone. For modelling, a spill of BTEX (benzene, toluene, ethylbenzene and xylene) is assumed near source zone. The developed model results are validated using three previously published datasets on flow, transport and biodegradation in the vadose zone. Simulations are performed for three types of soil, including clay, sand and loam. The analysis shows that sand has a maximum infiltration rate and clay has a minimum. Hydraulic conductivity and saturation profile peaks reach their minimal value at a shallower depth (around four times) when bioclogging is present compared to when it is absent. The migration depth and concentration of BTEX are observed to be restricted to a shallower depth in aquifers with the presence of microbial clogging. The outcome shows that electron acceptor consumption is more (around sevenfold for oxygen, fourfold for nitrate and threefold for sulphate) in the presence of bioclogging at the shallower zone. Zeroth order spatial moment and sensitivity analyses show that biological clogging, number of electron acceptors and inhibition constant substantially affect BTEX bioremediation in the vadose zone.

Treatment of low-pH rubber wastewater using ureolytic bacteria and the production of calcium carbonate precipitate for soil stabilization.

Rubber wastewater contains variable low pH with a high load of nutrients such as nitrogen, phosphorous, suspended solids, high biological oxygen demand (BOD), and chemical oxygen demand (COD). Ureolytic and biofilm-forming bacterial strains Bacillus sp. OS26, Bacillus cereus OS36, Lysinibacillus macroides ST13, and Burkholderia multivorans DF12 were isolated from rubber processing centres showed high urease activity. Microscopic analyses evaluated the structural organization of biofilm. Extracellular polymeric substances (EPS) matrix of the biofilm of the strains showed the higher abundance of polysaccharides and lipids which help in the attachment and absorption of nutrients. The functional groups of polysaccharides, proteins, and lipids present in EPS were revealed by ATR-FTIR and 1H NMR. A consortium composed of B. cereus OS36, L. macroides ST13, and B. multivorans DF12 showed the highest biofilm formation, and efficiently reduced 62% NH3, 72% total nitrogen, and 66% PO43-. This consortium also reduced 76% BOD, 61% COD, and 68% TDS. After bioremediation, the pH of the remediated wastewater increased to 11.19. To reduce the alkalinity of discharged wastewater, CaCl2 and urea were added for calcite reaction. The highest CaCO3 precipitate was obtained at 24.6 mM of CaCl2, 2% urea, and 0.0852 mM of nickel (Ni2+) as a co-factor which reduced the pH to 7.4. The elemental composition of CaCO3 precipitate was analyzed by SEM-EDX. XRD analysis of the bacterially-induced precipitate revealed a crystallinity index of 0.66. The resulting CaCO3 precipitate was used as soil stabilizer. The precipitate filled the void spaces of the treated soil, reduced the permeability by 80 times, and increased the compression by 8.56 times than untreated soil. Thus, CaCO3 precipitated by ureolytic and biofilm-forming bacterial consortium through ureolysis can be considered a promising approach for neutralization of rubber wastewater and soil stabilization.

Eggshell waste bioprocessing for sustainable acid phosphatase production and minimizing environmental hazards.

BACKGROUND: The Environmental Protection Agency has listed eggshell waste as the 15th most significant food industry pollution hazard. Using eggshell waste as a renewable energy source has been a hot topic recently. Therefore, finding a sustainable solution for the recycling and valorization of eggshell waste by investigating its potential to produce acid phosphatase (ACP) and organic acids by the newly-discovered B. sonorensis was the target of the current investigation. RESULTS: Drawing on both molecular and morphological characterizations, the most potent ACP-producing B. sonorensis strain ACP2, was identified as a local bacterial strain obtained from the effluent of the paper and pulp industries. The use of consecutive statistical experimental approaches of Plackett-Burman Design (PBD) and Orthogonal Central Composite Design (OCCD), followed by pH-uncontrolled cultivation conditions in a 7 L bench-top bioreactor, revealed an innovative medium formulation that substantially improved ACP production, reaching 216 U L-1 with an ACP yield coefficient Yp/x of 18.2 and a specific growth rate (µ) of 0.1 h-1. The metals Ag+, Sn+, and Cr+ were the most efficiently released from eggshells during the solubilization process by B. sonorensis. The uncontrolled pH culture condition is the most suitable and favoured setting for improving ACP and organic acids production. Quantitative and qualitative analyses of the produced organic acids were carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lactic acid, citric acid, and hydroxybenzoic acid isomer were the most common organic acids produced throughout the cultivation process. The findings of TGA, DSC, SEM, EDS, FTIR, and XRD analysis emphasize the significant influence of organic acids and ACP activity on the solubilization of eggshell particles. CONCLUSIONS: This study emphasized robust microbial engineering approaches for the large-scale production of a newly discovered acid phosphatase, accompanied by organic acids production from B. sonorensis. The biovalorization of the eggshell waste and the production of cost-effective ACP and organic acids were integrated into the current study, and this was done through the implementation of a unique and innovative medium formulation design for eggshell waste management, as well as scaling up ACP production on a bench-top scale.

Enzymatic and non-enzymatic removal of organic micropollutants with spent mushroom substrate of Agaricus bisporus.

Water bodies are increasingly contaminated with a diversity of organic micropollutants (OMPs). This impacts the quality of ecosystems due to their recalcitrant nature. In this study, we assessed the removal of OMPs by spent mushroom substrate (SMS) of the white button mushroom (Agaricus bisporus) and by its aqueous tea extract. Removal of acesulfame K, antipyrine, bentazon, caffeine, carbamazepine, chloridazon, clofibric acid, and N, N-diethyl-meta-toluamide (DEET) by SMS and its tea was between 10 and 90% and 0-26%, respectively, in a 7-day period. Sorption to SMS particles was between 0 and 29%, which can thus not explain the removal difference between SMS and its tea, the latter lacking these particles. Carbamazepine was removed most efficiently by both SMS and its tea. Removal of OMPs (except caffeine) by SMS tea was not affected by heat treatment. By contrast, heat-treatment of SMS reduced OMP removal to < 10% except for carbamazepine with a removal of 90%. These results indicate that OMP removal by SMS and its tea is mediated by both enzymatic and non-enzymatic activities. The presence of copper, manganese, and iron (0.03, 0.88, and 0.33 µg L-1, respectively) as well as H2O2 (1.5 µM) in SMS tea indicated that the Fenton reaction represents (part of) the non-enzymatic activity. Indeed, the in vitro reconstituted Fenton reaction removed OMPs > 50% better than the teas. From these data it is concluded that spent mushroom substrate of the white button mushroom, which is widely available as a waste-stream, can be used to purify water from OMPs.

Vermicomposting technology as a dynamic strategy to mitigate environmental crisis: a bibliometric study of last three decades.

Efficient recycling of resources forms the cornerstone of sustainable development. Among multiple options in stock for waste recycling, vermicomposting technology is regarded as a futuristic strategy, being tested in every part of the globe due to easy accessibility. Hence, a bibliometric study was planned to set a sight on global scientific trends encompassing vermicomposting research in last three decades. The data were retrieved from Google Scholar, Scopus and PubMed. Publications from different search engines were filtered out and 2064 unique documents were collected and illustrated in MS Excel and Vos-viewer. Inferences were drawn on significant aspects, such as publication growth trend, journal analysis and co-occurrence of keywords. The study revealed that the number of publications increased from 3 in 1992 to 166 in 2021. The number of citations also increased and peaked at 4314 in 2015. Following this, we clustered keywords using principle component analysis and worked out links between domains of vermicomposting. Vermicomposting conjoined to words substrate manipulation, quality improvement, heavy metal adsorption, and yield parameters. This implies that vermicompost is being explored for many alternate uses in addition to its use as a fertiliser. We concluded that vermicomposting is one of the promising technologies for waste recycling. It modulates plant growth and subdues stress in plants. Additionally, being an efficient adsorbent, it serves bioremediation of contaminated sites. Therefore, the future of this technology lies in synthesising nano-formulations, integrating into biosensor technology, simulating for predicting timelines under different conditions and making efforts to improve their adsorption.

Bioprospecting of extremophilic perchlorate-reducing bacteria: report of promising Bacillus spp. isolated from sediments of the bay of Cartagena, Colombia.

Three extremophile bacterial strains (BBCOL-009, BBCOL-014 and BBCOL-015), capable of degrading high concentrations of perchlorate at a range of pH (6.5 to 10.0), were isolated from Colombian Caribbean Coast sediments. Morphological features included Gram negative strain bacilli with sizes averaged of 1.75 × 0.95, 2.32 × 0.65 and 3.08 × 0.70 µm, respectively. The reported strains tolerate a wide range of pH (6.5 to 10.0); concentrations of NaCl (3.5 to 7.5% w/v) and KClO4- (250 to 10000 mg/L), reduction of KClO4- from 10 to 25%. LB broth with NaCl (3.5-30% w/v) and KClO4- (250-10000 mg/L) were used in independent trials to evaluate susceptibility to salinity and perchlorate, respectively. Isolates increased their biomass at 7.5 % (w/v) NaCl with optimal development at 3.5 % NaCl. Subsequently, ClO4- reduction was assessed using LB medium with 3.5% NaCl and 10000 mg/L ClO4-. BBCOL-009, BBCOL-014 and BBCOL-015 achieved 10%, 17%, and 25% reduction of ClO4-, respectively. The 16 S rRNA gene sequence grouped them as Bacillus flexus T6186-2, Bacillus marisflavi TF-11 (T), and Bacillus vietnamensis 15 - 1 (T) respectively, with < 97.5% homology. In addition, antimicrobial resistance to ertapenem, vancomycine, amoxicillin clavulanate, penicillin, and erythromycin was present in all the isolates, indicating their high adaptability to stressful environments. The isolated strains from marine sediments in Cartagena Bay, Colombia are suitable candidates to reduce perchlorate contamination in different environments. Although the primary focus of the study of perchlorate-reducing and resistant bacteria is in the ecological and agricultural realms, from an astrobiological perspective, perchlorate-resistant bacteria serve as models for astrobiological investigations.

Microorganism-mediated biodegradation for effective management and/or removal of micro-plastics from the environment: a comprehensive review.

Micro- plastics (MPs) pose significant global threats, requiring an environment-friendly mode of decomposition. Microbial-mediated biodegradation and biodeterioration of micro-plastics (MPs) have been widely known for their cost-effectiveness, and environment-friendly techniques for removing MPs. MPs resistance to various biocidal microbes has also been reported by various studies. The biocidal resistance degree of biodegradability and/or microbiological susceptibility of MPs can be determined by defacement, structural deformation, erosion, degree of plasticizer degradation, metabolization, and/or solubilization of MPs. The degradation of microplastics involves microbial organisms like bacteria, mold, yeast, algae, and associated enzymes. Analytical and microbiological techniques monitor microplastic biodegradation, but no microbial organism can eliminate microplastics. MPs can pose environmental risks to aquatic and human life. Micro-plastic biodegradation involves fragmentation, assimilation, and mineralization, influenced by abiotic and biotic factors. Environmental factors and pre-treatment agents can naturally degrade large polymers or induce bio-fragmentation, which may impact their efficiency. A clear understanding of MPs pollution and the microbial degradation process is crucial for mitigating its effects. The study aimed to identify deteriogenic microorganism species that contribute to the biodegradation of micro-plastics (MPs). This knowledge is crucial for designing novel biodeterioration and biodegradation formulations, both lab-scale and industrial, that exhibit MPs-cidal actions, potentially predicting MPs-free aquatic and atmospheric environments. The study emphasizes the urgent need for global cooperation, research advancements, and public involvement to reduce micro-plastic contamination through policy proposals and improved waste management practices.

Harnessing the potential of microalgae-based systems for mitigating pesticide pollution and its impact on their metabolism.

Due to increased pesticide usage in agriculture, a significant concentration of pesticides is reported in the environment that can directly impact humans, aquatic flora, and fauna. Utilizing microalgae-based systems for pesticide removal is becoming more popular because of their environmentally friendly nature, ability to degrade pesticide molecules into simpler, nontoxic molecules, and cost-effectiveness of the technology. Thus, this review focused on the efficiency, mechanisms, and factors governing pesticide removal using microalgae-based systems and their effect on microalgal metabolism. A wide range of pesticides, like atrazine, cypermethrin, malathion, trichlorfon, thiacloprid, etc., can be effectively removed by different microalgal strains. Some species of Chlorella, Chlamydomonas, Scenedesmus, Nostoc, etc., are documented for >90% removal of different pesticides, mainly through the biodegradation mechanism. The antioxidant enzymes such as ascorbate peroxidase, superoxide dismutase, and catalase, as well as the complex structure of microalgae cell walls, are mainly involved in eliminating pesticides and are also crucial for the defense mechanism of microalgae against reactive oxygen species. However, higher pesticide concentrations may alter the biochemical composition and gene expression associated with microalgal growth and metabolism, which may vary depending on the type of strain, the pesticide type, and the concentration. The final section of this review discussed the challenges and prospects of how microalgae can become a successful tool to remediate pesticides.

Bioremediation and bioscavenging for elimination of organophosphorus threats: An approach using enzymatic advancements.

Organophosphorus compounds (OP) are highly toxic pesticides and nerve agents widely used in agriculture and chemical warfare. The extensive use of these chemicals has severe environmental implications, such as contamination of soil, water bodies, and food chains, thus endangering ecosystems and biodiversity. Plants absorb pesticide residues, which then enter the food chain and accumulate in the body fat of both humans and animals. Numerous human cases of OP poisoning have been linked to both acute and long-term exposure to these toxic OP compounds. These compounds inhibit the action of the acetylcholinesterase enzyme (AChE) by phosphorylation, which prevents the breakdown of acetylcholine (ACh) neurotransmitter into choline and acetate. Thus, it becomes vital to cleanse the environment from these chemicals utilizing various physical, chemical, and biological methods. Biological methods encompassing bioremediation using immobilized microbes and enzymes have emerged as environment-friendly and cost-effective approaches for pesticide removal. Cell/enzyme immobilized systems offer higher stability, reusability, and ease of product recovery, making them ideal tools for OP bioremediation. Interestingly, enzymatic bioscavengers (stoichiometric, pseudo-catalytic, and catalytic) play a vital role in detoxifying pesticides from the human body. Catalytic bioscavenging enzymes such as Organophosphate Hydrolase, Organophosphorus acid anhydrolase, and Paraoxonase 1 show high degradation efficiency within the animal body as well as in the environment. Moreover, these enzymes can also be employed to decontaminate pesticides from food, ensuring food safety and thus minimizing human exposure. This review aims to provide insights to potential collaborators in research organizations, government bodies, and industries to bring advancements in the field of bioremediation and bioscavenging technologies for the mitigation of OP-induced health hazards.

Isolation and characterization of novel cadmium-resistant Escherichia fergusonii ZSF-15 from industrial effluent for flocculant production and antioxidant enzyme activity.

Cadmium (Cd) is a highly toxic metal that frequently contaminates our environment. In this study, the bioflocculant-producing, cadmium-resistant Escherichia fergusonii ZSF-15 was characterized from Paharang drain, Bawa Chak, Faisalabad, Pakistan. The Cd-resistant E. fergusonii was used to determine the bioflocculant production using yeast-peptone-glycerol medium (pH 6.5) supplemented with 50 mg L-1 of Cd. The culture was incubated for 3 days at 37 °C in a rotary shaker at 120 rpm. The fermentation broth was centrifuged at 4000 g for 10 min after the incubation period. The maximum flocculating activity by isolate ZSF-15 was found to be 71.4% after 48 h of incubation. According to the Fourier transform infrared spectroscopy analysis, the bioflocculant produced by strain ZSF-15 was comprised of typical polysaccharide and protein, i.e. hydroxyl, carboxyl, and amino groups. The strain ZSF-15 exhibited bioflocculant activity at range of pH (6-8) and temperature (35-50℃). Maximum flocculation activity (i.e. 71%) was observed at 47℃, whereas 63% flocculation production was observed at pH 8. In the present study, antioxidant enzyme profile of ZSF-15 was also evaluated under cadmium stress. A significant increase in antioxidant enzymes including superoxide dismutase (118%) and ascorbate peroxidase (28%) was observed, whereas contents of catalase (86%), glutathione transferase (13%), and peroxidase (8%) were decreased as compared to control.

Exogenous compound bacteria enhance the nutrient removal efficiency of integrated bioremediation systems: Functional genes and microorganisms play key roles.

With the continuous development of intensive mariculture, the application of the integrated bioremediation system of aquaculture wastewater (IBSAW) is increasingly promoted. However, the process and nutrients removal performance of the IBSAW need to be further optimized due to its immature technologies. In this study, exogenous compound bacteria (ECB) were added to IBSAW to investigate its pollutants removal efficiency and the relevant mechanisms. High-throughput sequencing and Geochip gene array were used to analyze the correlation between nutrients and bacteria, and the abundance of N and P cycling genes were quantified. Multivariable statistics, dimensionality reduction analysis, and network analysis were applied to explore the mechanisms of IBSAW operation. The results showed that the nutrients decreased significantly after adding ECB, with the brush treatment group significantly outperforming the ceramsite in removing NO3- and PO43-. Ceramsite has an advantage in removing NO2--N. The addition of ECB and different substrates significantly affected the composition of bacterial communities. The contents of nosZ and nirKS related to denitrification in the treatment groups were significantly higher than those in the control group, and the contents in the brush treatment group were significantly higher than that of ceramsite. The biomarkers Psychroserpens and Ruegeria on the biofilm of the brush treatment group were positively correlated with nirKS, while Mycobacterium, Erythrobacter and Paracoccus, Pseudohaliea in the ceramsite group were positively correlated with nirS and nirK, respectively. Therefore, it is speculated that the ECB significantly promoted the increase of denitrification bacteria by affecting the composition of bacterial communities, and the ECB combined with functional genera improved the efficiency of nutrients removal in the system. This study provided a reference for understanding the process and mechanism of nutrients removal, optimizing the wastewater purification technology of the IBSAW and improving the performance of the system.

Heterologous expression, biochemical characterization and prospects for insecticide biosensing potential of carboxylesterase Ha006a from Helicoverpa armigera.

Enzymes have attracted considerable scientific attention for their crucial role in detoxifying a wide range of harmful compounds. In today's global context, the extensive use of insecticides has emerged as a significant threat to the environment, sparking substantial concern. Insects, including economically important pests like Helicoverpa armigera, have developed resistance to conventional pest control methods through enzymes like carboxyl/cholinesterases. This study specifically focuses on a notable carboxyl/cholinesterase enzyme from Helicoverpa armigera (Ha006a), with the goal of harnessing its potential to combat environmental toxins. A total of six insecticides belonging to two different classes displayed varying inhibitory responses towards Ha006a, thereby rendering it effective in detoxifying a broader spectrum of insecticides. The significance of this research lies in discovering the bioremediation property of Ha006a, as it hydrolyzes synthetic pyrethroids (fenvalerate, λ-cyhalothrin and deltamethrin) and sequesters organophosphate (paraoxon ethyl, profenofos, and chlorpyrifos) insecticides. Additionally, the interaction studies between organophosphate insecticides and Ha006a helped in the fabrication of a novel electroanalytical sensor using a modified carbon paste electrode (MCPE). This sensor boasts impressive sensitivity, with detection limits of 0.019 µM, 0.15 µM, and 0.025 µM for paraoxon ethyl, profenofos, and chlorpyrifos, respectively. This study provides a comprehensive biochemical and biophysical characterization of the purified esterase Ha006a, showcasing its potential to remediate different classes of insecticides.

Trends in Antarctic soil fungal research in the context of environmental changes.

Antarctic soils represent one of the most pristine environments on Earth, where highly adapted and often endemic microbial species withstand multiple extremes. Specifically, fungal diversity is extremely low in Antarctic soils and species distribution and diversity are still not fully characterized in the continent. Despite the unique features of this environment and the international interest in its preservation, several factors pose severe threats to the conservation of inhabiting ecosystems. In this light, we aimed to provide an overview of the effects on fungal communities of the main changes endangering the soils of the continent. Among these, the increasing human presence, both for touristic and scientific purposes, has led to increased use of fuels for transport and energy supply, which has been linked to an increase in unintentional environmental contamination. It has been reported that several fungal species have evolved cellular processes in response to these soil contamination episodes, which may be exploited for restoring contaminated areas at low temperatures. Additionally, the effects of climate change are another significant threat to Antarctic ecosystems, with the expected merging of previously isolated ecosystems and their homogenization. A possible reduction of biodiversity due to the disappearance of well-adapted, often endemic species, as well as an increase of biodiversity, due to the spreading of non-native, more competitive species have been suggested. Despite some studies describing the specialization of fungal communities and their correlation with environmental parameters, our comprehension of how soil communities may respond to these changes remains limited. The majority of studies attempting to precisely define the effects of climate change, including in situ and laboratory simulations, have mainly focused on the bacterial components of these soils, and further studies are necessary, including the other biotic components.

Comprehensive bioremediation effect of phosphorus-mineralized bacterium Enterobacter sp. PMB-5 on cadmium contaminated soil-crop system.

Phosphate-mineralizing bacteria (PMBs) have been widely studied by inducing phosphate heavy metal precipitation, but current researches neglect to study their effects on soil-microbe-crop systems on cadmium (Cd) contaminated. Based on this, a strain PMB, Enterobacter sp. PMB-5, was inoculated into Cd contaminated pots to detect soil characteristics, Cd occurrence forms, soil biological activities, plant physiological and biochemical indicators. The results showed that the inoculation of strain PMB-5 significantly increased the available phosphorus content (85.97%-138.64%), Cd-residual fraction (11.04%-29.73%), soil enzyme activities (31.94%-304.63%), plant biomass (6.10%-59.81%), while decreased the state of Cd-HOAc (11.50%-31.17%) and plant bioconcentration factor (23.76%-44.24%). These findings indicated that strain PMB-5 could perform the function of phosphorus solubilization to realize the immobilization of Cd in the complex soil environment. Moreover, SEM-EDS, FTIR, XPS, and XRD analysis revealed that strain PMB-5 does not significantly alter the soil morphology, structure, elemental distribution, and chemical composition, which suggested that remediation of Cd contamination using strain PMB-5 would not further burden the soil. This research implies that PMB-5 could be a safe and effective bioinoculant for remediating Cd-contaminated soils, contributing to the sustainable management of soil health in contaminated environments.

Enhancement of benzo[a]pyrene mineralization: symbiotic biodegradation by Acinetobacter sp. strain HAP1 in Association with Cyanobacteriota sp. S66.

The ability of Acinetobacter sp. strain HAP1, isolated from petroleum refinery effluent, to eliminate different concentrations (20, 40, 60, 80 and 100 mg/L) of Benzo[a]Pyrene degradation (BaP) was studied. A test to improve this degradation capacity was carried out by culturing the bacterial strain in association with a cyanobacteria. The results show a highly significant effect of the concentration of (BaP) and a very highly significant effect of the symbiosis between the bacterial strain and the cyanobacteria. This combination was able to significantly improve the (BaP) degradation rate by up to 18%. This degradation and especially in association leads to a complete mineralization of (BaP) and there is a difference in yield that can go up to 15%. Through molecular identification based on 16S rRNA gene sequence analysis, strains HAP1 and S66 were recognized as Acinetobacter sp. strain HAP1 and Cyanobacteriota sp. S66, respectively. Comparison of the retrieved sequences with the NCBI GenBank database was done, and the closest matches were found to be Acinetobacter pittii strain JD-10 for bacteria and Pseudochroococcus couteii strain PMC 885.14 for cyanobacteria.

Insights into the differential proteome landscape of a newly isolated Paramecium multimicronucleatum in response to cadmium stress.

Employing microbial systems for the bioremediation of contaminated waters represent a potential option, however, limited understanding of the underlying mechanisms hampers the implication of microbial-mediated bioremediation. The omics tools offer a promising approach to explore the molecular basis of the bioremediation process. Here, a mass spectrometry-based quantitative proteome profiling approach was conducted to explore the differential protein levels in cadmium-treated Paramecium multimicronucleatum. The Proteome Discoverer software was used for the identification and quantification of the differentially abundant proteins. The proteome profiling generated 7416 peptide spectral matches, yielding 2824 total peptides, corresponding to 989 proteins. The analysis revealed 29 proteins exhibited significant (p ≤ 0.05) differential levels, including higher abundance of 6 proteins and reduced levels of 23 proteins in Cd2+ treated samples. These differentially abundant proteins were found to be associated with stress response, energy metabolism, protein degradation, cell growth, and hormone processing. Briefly, a comprehensive proteome profile in response to cadmium stress of a newly isolated Paramecium has been established that will be useful in future studies identifying critical proteins involved in the bioremediation of metals in ciliates. SIGNIFICANCE: Ciliates are considered a good biological indicator of chemical pollution and relatively sensitive to heavy metal contamination. A prominent ciliate, Paramecium is a promising candidate for the bioremediation of polluted water. The proteins related to metal resistance in Paramecium species are still largely unknown and need further exploration. In order to identify and reveal the proteins related to metal resistance in Paramecia, we have reported differential protein expressions in Paramecium multimicronucleatum in response to cadmium stress. The proteins found in our study play essential roles during stress response, hormone processing, protein degradation, energy metabolism, and cell growth. It seems likely that Paramecia are not a simple sponge for metals but they could also transform them into less toxic derivatives or by detoxification by protein binding. This data will be helpful in future studies to identify critical proteins along with their detailed mechanisms involved in the bioremediation and detoxification of metal ions in Paramecium species.