Bioremediation Process Research Articles

Safety attributes of Pseudomonas sp. P26, an environmental microorganism with potential application in contaminated environments

Currently, the selection of non-pathogenic microorganisms that lack clinically relevant antimicrobial resistance is crucial to bioaugmentation strategies. Pseudomonas sp. P26 (P26) is an environmental bacterium of interest due to its ability to remove aromatic compounds from petroleum, but its safety characteristics are still unknown. The study aimed to: a) determine P26 sensitivity to antimicrobials, b) investigate the presence of quinolone and β-lactam resistance genes, c) determine the presence of virulence factors, and d) evaluate the effect of P26 on the viability of Galleria mellonella (an invertebrate animal model). P26 antimicrobial sensitivity was determined in vitro using the Kirby-Bauer agar diffusion method and the VITEK 2 automated system (BioMerieux®). Polymerase Chain Reaction was employed for the investigation of genes associated with quinolone resistance, extended-spectrum β-lactamases, and carbapenemases. Hemolysin and protease production was determined in human blood agar and skimmed-milk agar, respectively. In the in vivo assay, different doses of P26 were injected into Galleria mellonella larvae and their survival was monitored daily. Control larvae injected with Pseudomonas putida KT2440 (a strain considered as safe) and Pseudomonas aeruginosa PA14 (a pathogenic strain) were included. Pseudomonas sp. P26 was susceptible to most evaluated antimicrobials, except for trimethoprim-sulfamethoxazole. No epidemiologically relevant genes associated with quinolone and β-lactam resistance were identified. Hemolysin and protease production was only evidenced in the virulent strain (PA14). Furthermore, the results obtained in the in vivo experiment demonstrated that inocula less than 108 CFU/mL of P26 and P. putida KT2440 did not significantly affect larval survival, whereas larvae injected with the lowest dose of the pathogenic strain P. aeruginosa PA14 experienced instant mortality. The results suggest that Pseudomonas sp. P26 is a safe strain for its application in environmental bioremediation processes. Additional studies will be conducted to ensure the safety of this bacterium against other organisms.

An update on Glycerophosphodiester Phosphodiesterases; From Bacteria to Human.

The hydrolysis of deacylated glycerophospholipids into sn-glycerol 3-phosphate and alcohol is facilitated by evolutionarily conserved proteins known as glycerophosphodiester phosphodiesterases (GDPDs). These proteins are crucial for the pathogenicity of bacteria and for bioremediation processes aimed at degrading organophosphorus esters that pose a hazard to both humans and the environment. Additionally, GDPDs are enzymes that respond to multiple nutrients and could potentially serve as candidate genes for addressing deficiencies in zinc, iron, potassium, and especially phosphate in important plants like rice. In mammals, glycerophosphodiesterases (GDEs) play a role in regulating osmolytes, facilitating the biosynthesis of anandamine, contributing to the development of skeletal muscle, promoting the differentiation of neurons and osteoblasts, and influencing pathological states. Due to their capacity to enhance a plant's ability to tolerate various nutrient deficiencies and their potential as pharmaceutical targets in humans, GDPDs have received increased attention in recent times. This review provides an overview of the functions of GDPD families as vital and resilient enzymes that regulate various pathways in bacteria, plants, and humans.

Isolation, characterization and identification of Klebsiella sp. dor_27f isolated from textile effluents

This research study aimed to isolate and characterize a new bacterial strain from textile effluents. To do this, bacteria were cultured using the MSM medium, where a colony was isolated through six successive pickings. It then underwent a DNA extraction process using the phenol-chloroform-isoamyl alcohol methodology, and an electrophoresis was carried out to confirm the extraction. In addition, the isolated colony was identified as Klebsiella sp. by sequencing the 16S rRNA gene using bioinformatics tools. To observe its biotechnological potential, the bacterial strain was grown in an MSM broth enriched with Golden Yellow K2R azoic dye at a concentration of 50 mg/L, showing a percentage of decolorization of 74 % after 72 hours at 37 °C, indicating the potential of the isolated colony for the development of bio-remediation processes for effluents containing azoic dyes. Keywords: Bacterial strain, Klebsiella sp., DNA extraction, decolorization, effluents.

Exploring macrophytes’ microbial populations dynamics to enhance bioremediation in constructed wetlands for industrial pollutants removal in sustainable wastewater treatment

AbstractToxic contaminants from intense industrial operations are entering wetlands, harming human health and biodiversity. Macrophytes serve as principal producers in aquatic environments including natural wetlands, providing shelter, food, and, most crucially, intricate relationships with the surrounding microbial assemblage for support and microorganisms attachment. Wetlands have been nature's kidneys, for filtering water. Recent research has examined macrophytes' phytoremediation abilities. With recent improvements focused on engineered wetland technology, microbiological characterization, and genetic engineering, phytoremediation strategies have also benefited. However, little research has examined the role surrounding microbial population play on macrophyte efficiency in pollutant degradation, the extent and even mechanisms of these interactions, and their potential utility in wastewater treatment of diverse industrial effluents. Our bid for greener solutions implies that macrophyte-microorganisms’ interspecific interactions for in situ treatment of effluents should be optimised to remove contaminants before discharge in natural waterbodies or for recycle water usage. This review provides for the varied types of plants and microbial interspecific interactions beneficial to effective phytoremediation processes in artificial wetland design as well as considerations and modifications in constructed wetland designs necessary to improve the bioremediation processes. Additionally, the review discusses the latest advancements in genetic engineering techniques that can enhance the effectiveness of phyto-assisted wastewater treatment. We will also explore the potential utilisation of invasive species for their demonstrated ability to remove pollutants in the controlled setting of constructed wetlands.

Constructed wetland as a green remediation technology for the treatment of wastewater from underground coal gasification process.

The wastewater from underground coal gasification (UCG) process has extremely complex composition and high concentrations of toxic and refractory compounds including phenolics, aliphatic and aromatic hydrocarbons, ammonia, cyanides, hazardous metals and metalloids. So, the development of biological processes for treating UCG wastewater poses a serious challenge in the sustainable coal industry. The aim of the study was to develop an innovative and efficient wetland construction technology suitable for a treatment of UCG wastewater using available and low-cost media. During the bioremediation process the toxicity of the raw wastewater decreased significantly between 74%-99%. The toxicity units (TU) ranged from values corresponding to very high acute toxic for raw wastewater to non-toxic for effluents from wetland columns after 60 days of the experiment. The toxicity results correlated with the decrease of some organic and inorganic compounds such as phenols, aromatic hydrocarbons, cyanides, metals and ammonia observed during the bioremediation process. The removal percentage of organic compounds like BTEX, PAHs and phenol was around 99% just after 14 days of treatment. A similar removal rate was indicated for cyanide and metals (Zn, Cr, Cd and Pb). Concluded, in order to effectively assess remediation technologies, it is desirable to consider combination of physicochemical parameters with ecotoxicity measurements. The present findings show that wetland remediation technology can be used to clean-up the heavily contaminated waters from the UCG process. Wetland technology as a nature-based solution has the potential to turn coal gasification wastewater into usable recycled water. It is economically and environmentally alternative treatment method.

Exploring the Role of Plants in Bio-remediation: Harnessing Nature's Clean-up Agents

The study investigates the vital role of plants in bio-remediation processes, capitalizing on their inherent ability to act as nature's clean-up agents. As industries continue to generate pollutants, there is a growing need for sustainable and eco-friendly approaches to mitigate environmental damage. This research delves into the diverse mechanisms by which plants contribute to bioremediation, including phytoremediation, rhizofiltration, and phytoextraction. The exploration encompasses the interactions between plant roots and soil microorganisms, as well as the potential for genetic modifications to enhance bio-remediation efficiency. By comprehensively analysing the scientific literature, this study aims to provide insights into harnessing the natural capabilities of plants for effective and environmentally friendly remediation strategies. The findings contribute to the on-going discourse on sustainable environmental management, offering promising avenues for the integration of plant-based solutions into mainstream bio-remediation practices.

Using Fungi in Artificial Microbial Consortia to Solve Bioremediation Problems.

There is currently growing interest in the creation of artificial microbial consortia, especially in the field of developing and applying various bioremediation processes. Heavy metals, dyes, synthetic polymers (microplastics), pesticides, polycyclic aromatic hydrocarbons and pharmaceutical agents are among the pollutants that have been mainly targeted by bioremediation based on various consortia containing fungi (mycelial types and yeasts). Such consortia can be designed both for the treatment of soil and water. This review is aimed at analyzing the recent achievements in the research of the artificial microbial consortia that are useful for environmental and bioremediation technologies, where various fungal cells are applied. The main tendencies in the formation of certain microbial combinations, and preferences in their forms for usage (suspended or immobilized), are evaluated using current publications, and the place of genetically modified cells in artificial consortia with fungi is assessed. The effect of multicomponence of the artificial consortia containing various fungal cells is estimated, as well as the influence of this factor on the functioning efficiency of the consortia and the pollutant removal efficacy. The conclusions of the review can be useful for the development of new mixed microbial biocatalysts and eco-compatible remediation processes that implement fungal cells.

A plant-wide modelling framework to describe microalgae growth on liquid digestate in agro-zootechnical biomethane plants

Microalgae cultivation on liquid digestate from the anaerobic co-digestion of agricultural feedstocks is an interesting option for digestate nutrient removal and resource recovery coupled to biomass generation. Both the reactors considered in such a biorefinery system involve complex bioprocesses. Although different pilot-scale systems coupling anaerobic digestion and algae-based bioremediation processes have been described, no previous attempts to model the entire system are available to date. In this work, a plant-wide model, named ADAB (anaerobic digestion algae-bacteria), is presented, coupling two well-established models for anaerobic digestion (IWA – ADM1) and algae-based bioremediation processes (ALBA). The models were modified with necessary equations and extensions to develop a dedicated model interface. Phosphorous dynamics were integrated, including activity corrections and precipitation processes. The ALBA model was also integrated with thermal modelling to simulate outdoor raceway ponds and greenhouse-covered systems. Solid/liquid separation units for digestate pre-treatment were also included. The prediction consistency of the adopted physicochemical sub-model (PCM) was verified with results from both reference literature and Visual MINTEQ. The reduced complexity of the PCM limits the model field of application, but it results in better computational performance and seems to be particularly suitable to simulate agro-zootechnical digesters. A scenario analysis including different co-digester design and operating conditions was carried out to assess the impacts on microalgae cultivation. It highlighted the importance of a proper biorefinery design and yet a noteworthy robustness of the system performance. The use of the ADAB model can facilitate a more realistic assessment of the technical, environmental, and economic feasibility of full-scale microalgal biorefineries based on digestate.

Bioremediation of petroleum hydrocarbon contaminated soil: a review on principles, degradation mechanisms, and advancements

Petroleum hydrocarbons (PHCs) are key energy sources for several industries and daily life. Soil contamination from oily PHC spills is commonly detected in cities and industrial facilities where crude oil is used. The release of PHC pollutants into the environment, whether accidentally from petroleum industries or human activities, has become a leading source of soil pollution. Consequently, the mineralization of PHC-polluted sites has become a central issue worldwide. Although bioremediation is imperative for environmental safety and management, several approaches have been developed for PHC bioremediation. However, much remains to be explored in this regard. This review explores bioremediation of PHC-contaminated soil and provides a comprehensive examination of the principles, degradation mechanisms, and recent advancements in the field. Several microbial species have been used to study the bioremediation of PHCs, emphasizing the pivotal roles of diverse microbial communities. Aspergillus spp., Proteobacteria, and Firmicutes groups of microorganisms were the most efficient in remediating PHC-contaminated soil. The fundamental concepts behind the bioremediation of PHC and the complex mechanisms that govern degradation were elucidated. Limiting factors in the bioremediation process and recent innovations propelling the field were also discussed. Therefore, understanding the degradation pathway, ensuring complete degradation of contaminants, and flexible legislation for the proper use of genetically engineered microbes can make bioremediation more sustainable and cost-effective.

Utility of metagenomics for bioremediation: a comprehensive review on bioremediation mechanisms and microbial dynamics of river ecosystem.

Global industrialization has contributed substantial amounts of chemical pollutants in rivers, resulting in an uninhabitable state and impacting different life forms. Moreover, water macrophytes, such as water hyacinths, are abundantly present in polluted rivers, significantly affecting the overall water biogeochemistry. Bioremediation involves utilizing microbial metabolic machinery and is one of the most viable approaches for removing toxic pollutants. Conventional techniques generate limited information on the indigenous microbial population and their xenobiotic metabolism, failing the bioremediation process. Metagenomics can overcome these limitations by providing in-depth details of microbial taxa and functionality-related information required for successful biostimulation and augmentation. An in-depth summary of the findings related to pollutant metabolizing genes and enzymes in rivers still needs to be collated. The present study details bioremediation genes and enzymes functionally mined from polluted river ecosystems worldwide using a metagenomic approach. Several studies reported a wide variety of pollutant-degrading enzymes involved in the metabolism of dyes, plastics, persistent organic pollutants, and aromatic hydrocarbons. Additionally, few studies also noted a shift in the microbiome of the rivers upon exposure to contaminants, crucially affecting the ecological determinant processes. Furthermore, minimal studies have focused on the role of water-hyacinth-associated microbes in the bioremediation potentials, suggesting the need for the bioprospecting of these lesser-studied microbes. Overall, our study summarizes the prospects and utilities of the metagenomic approach and proposes the need to employ it for efficient bioremediation.

Bioremediation potential of the Chlorella and Scenedesmus microalgae in explosives production effluents

This study explores microalgae-based bioremediation for treating black gunpowder production effluents, an understudied yet environmentally significant stream. Two native microalgae, Chlorella sp. MC18 (CH) and Scenedesmus sp. MJ23-R (SC), were assessed for growth kinetics and nutrient removal capabilities in culture media containing different proportions of untreated raw wastewater. Results show both species thrived in 100 % raw wastewater, displaying robust growth and substantial biomass production in parallelepiped-shaped photobioreactors. SC showed superior performance, with higher maximum specific growth rate (0.549 d−1), biomass yield (454.57 mg L−1) and biomass productivity (64.94 mg L−1 d−1) compared to CH (0.524 d−1, 380.60 mg L−1, 54.37 mg L−1 d−1, respectively). The use of 100 % raw wastewater as a culture medium eliminated the need for additional freshwater input, thus reducing the water footprint. The bioremediation process also resulted in a high removal efficiency in turbidity (>95 % CH, >76 % SC), total suspended solids (>93 % CH, >74 % SC), biochemical oxygen demand (BOD5) (>62 % CH, >93 % SC) and chemical oxygen demand (COD) (>63 % CH, >87 % SC), bringing the effluent into compliance with environmental regulations. Although nitrogen (>45 % CH, >57 % SC) and sulphate (>43 % CH, >35 % SC) removal efficiencies was high, potassium bioremediation was limited (<6 %). The proximate chemical composition of the microalgal biomass revealed different allocations to carbohydrates, lipids and proteins. The results suggest promising applications for biofuel production and aquaculture. This research highlights the potential of microalgae-based bioremediation for sustainable wastewater management in the explosives industry, contributing to the UN Sustainable Development Goals and promoting green industrial practices.

Mycoremediation Approach to Green Air: Phenanthrene and Anthracene Degrading Ability by Fusarium solani Isolate P11M-46

There are many health issues associated with air pollution that are rapidly increasing with time across the globe. Among many air pollutants, polycyclic aromatic hydrocarbons (PAHs) are of particular concern because of their carcinogenicity, genotoxicity, and long persistence in the environment. The majority of these PAHs release into the air through anthropogenic activities and natural sources. After releasing into the air, PAHs usually return to the ground due to their high molecular weight. These hydrocarbon depositions can be categorized as wet or dry depositions. One of the most prominent deposition surfaces of these pollutants is the phyllosphere. Microorganisms such as fungi perform a key role in PAHs elimination through bioremediation processes. Epiphytic fungi such as Fusarium solani isolate P11M-46 utilizes the deposited phenanthrene and anthracene on the phyllosphere and convert those PAHs in to non-toxic levels. The aim of this study was to evaluate the ability of F. solani isolate P11M-46 to degrade phenanthrene and anthracene, through a mycoremediation approach. Leaf samples were collected from Panchikawatta, Orugodawatta, Pettah, Maradana, Colombo Fort, and Sapugaskanda urban areas in Sri Lanka. Furthermore, PAH degradation ability of isolated F. solani isolate P11M-46 was confirmed through High Performance Liquid Chromatography (HPLC). The effects of by-products produced from the biodegradation process on living beings were evaluated using Artemia salina and the by-products were identified using Gas Chromatography and Mass Spectrometry (GCMS). According to HPLC results, F. solani isolate P11M-46 showed 68% of degradation percentage in phenanthrene while exhibiting 76% degradation in anthracene within 6 days. The GCMS analysis confirmed that the by-products were Phenol, 2-(phenylmethyl) from phenanthrene and 9, 10-anthracenedione from anthracene. Toxicity assay with A. salina confirmed that these byproducts were not toxic to the phyllosphere. The findings of the present study revealed the potential use of phyllosphere F. solani isolate P11M-46 in the remediation of environmental pollutants phenanthrene and anthracene. And also the by-products produced during their degradation mechanism were also confirmed as nontoxic compounds. Therefore, F. solani isolate P11M-46 could be effectively used in the bioremediation of phenanthrene and anthracene in polluted environments as a bioremediator. &#x0D; Keywords: Polycyclic aromatic hydrocarbons, Bioremediation, HPLC, GCMS, Toxicity

Upaya Pengelolaan Lingkungan Akibat Bencana Banjir di Kecamatan Empang, Kabupaten Sumbawa

Indonesia is a country that is prone to natural disasters from a geological perspective. Based on information from the Head of the Information Data Center and Public Relations of the National Disaster Management Agency, natural disaster trends have increased by 350% in the last three decades. A significant increase is hydrometeorological disasters which are influenced by weather aspects, such as floods, landslides, tornadoes, and droughts. Sumbawa Regency is one of the areas in Indonesia that is being hit by an increasing trend of natural disasters. The most recent natural disaster that hit one of the Sumbawa Regency areas was the flood disaster in Empang District. The cause of flooding itself can occur due to various things both natural and human. Floods can be caused by natural events such as rainfall over a long period of time, soil flooding leaving only rocks, and no water absorption. Therefore it is essential to analyze the flood disaster that occurred in Empang District so that a good environmental management strategy can be carried out. The management carried out is to restore environmental functions that have been lost due to damage caused by the disaster. Installing drainage and implementing the Internet of Things in overcoming flooding is considered to be quite effective. The relocation and reclamation activities of corn plantation areas carried out by bioremediation and revegetation processes can improve land conditions.

Isolation and Influence of Carbon Source on the Production of Extracellular Polymeric Substance by Bacteria for the Bioremediation of Heavy Metals in Santo Amaro City

The city of Santo Amaro (Bahia, Brazil) gained visibility among the scientific community due to the contamination of the Subaé River by lead and cadmium from the PLUMBUM Mineração e Metalurgia Ltda industry, on the banks of the river in 1956, which produced lead ingots The present work aimed to investigate the adsorption capacity of heavy metals (Pb and Cd) of EPS produced by bacterial species from the Subaé River, for possible future application of these biopolymers in bioremediation processes in areas impacted by the aforementioned heavy metals. Subaé river water was collected for physical-chemical analysis and bacterial isolation. It was verified that all isolated bacteria produced an expressive amount of Exopolysaccharide (EPS). Thus, the optimization of this production in different sugars (sucrose, glucose, and mannitol) and in three different pHs: 5.5; 6.5, and 7.5. All bacteria produced EPS in large quantities and the best sugar was sucrose at pH 7.5. In order to use the EPS for the bioremediation area, the adsorption test of lead and cadmium was carried out by the isolated EPS. 0.5 g of the EPS was dissolved in 50 ml of deionized water, then the solutions of metals, lead acetate, and cadmium sulfate (procedure performed separately) were incubated at 28 °C for 16 h after that period, and were centrifuged. Samples were filtered to separate the insoluble EPS and the filtrates obtained were used in the quantification of the metals by atomic absorption (FAAS- Flame Atomic Absorption Spectrometry). Bacillus spp., Bacillus cereus, Staphylococcus spp., and Serratiamarcescens, all showed tolerance to the tested metals, due to the efficiency in the adsorption capacity of the EPS, and it was possible to distinguish seven genera, Klebsiella pneumonia, Pseudomonas aeruginosa, Lysinibacillus spp. to be used in the bioremediation of environments contaminated with heavy metals.

Characterization of a biosurfactant produced by Peruvian strain Pseudomonas aeruginosa 6K‐11

AbstractBACKGROUNDThe oil industry has a big impact on the environment by itself and by using chemically synthesized surfactants. Biosurfactants are an ecofriendly alternative, especially rhamnolipids produced by Pseudomonas aeruginosa. Rhamnolipids in a determined concentration decrease the liquid surface tension, and this allows access oil hydrocarbon to be degraded. The objective of this research is to characterize the biosurfactant produced by the native strain P. aeruginosa 6K‐11 by determining its critical micelle concentration (CMC), Krafft point, and emulsifying activity.RESULTSExperiments were initially performed with rhamnolipid produced by P. aeruginosa 6K‐11 growing on Siegmund‐Wagner medium with 1% of waste oil as carbon source and at 31.26 °C, 186 rpm after 42 h of incubation. After that, the biosurfactant was purified according to acid precipitation methodology. The first conductivity measurement, 34 μS/cm, was obtained with 12.5 g/L of rhamnolipid by using an APERA conductivity meter. The rhamnolipid CMC was 5.86 g/L due to the conductivity measurements graph and 0.49 was the dissociation degree. The equations of both lines were found by the method of least squares. The rhamnolipid has produced 1.97 Units of Emulsifying Activity (UEA) and 50% stability was observed based on the E24 Index. The highest conductivity achieved under 39 °C, as calculated from a conductivity against temperature graph, was the Krafft point.CONCLUSIONThese findings give important parameters to characterize the P. aeruginosa 6K‐11 biosurfactant activity that can be used to accelerate oil biodegradation in bioremediation processes. © 2024 Society of Chemical Industry (SCI).

Optimization of mineral nutrients to improve rhamnolipid production by Pseudomonas aeruginosa6 K‐11

AbstractBACKGROUNDRhamnolipids are biosurfactants that have their main application in bioremediation processes. They are able to increase the biodegradation and detoxification rates from industrial effluents. The north of Peru and Iquitos have been not only major oil producers but also have been responsible for oil spills. This study therefore focused on the optimization of mineral nutrients such as nitrogen, phosphorous, calcium and iron to improve rhamnolipids production by Pseudomonas aeruginosa 6 K‐11, which was isolated from oil soil in Peru.RESULTSPseudomonas aeruginosa 6 K‐11 was reactivated in Trypticase Soy Broth by scaling from 5 to 200 mL of culture medium for 8 h at each stage. The culture was centrifuged and placed in 100 mL Siegmund–Wagner medium for 36 h in a 500 mL Erlenmeyer flask. First, it was determined that sodium nitrate, monopotassium phosphate, calcium chloride and iron sulfate were the best sources of mineral nutrients. Then, by using corn oil as carbon source, the ratios obtained for carbon‐to‐nitrogen and carbon‐to‐phosphorous were 21.172 and 16.279, respectively. In addition, it was found that the optimal concentration for calcium was 0.046 g L−1 and for iron was 0.003 g L−1. The most influential variables were carbon‐to‐nitrogen and carbon‐to‐phosphorus ratio. Finally, 35.124 g L−1 rhamnolipids was produced after 168 h of fermentation with the optimal parameters.CONCLUSIONThe optimization of mineral nutrients was an important achieved goal for rhamnolipid production. In addition, this optimization can be used for modifying the culture medium to grow the biosurfactant producer strain. © 2024 Society of Chemical Industry (SCI).

Biotransformation of diclofenac by isolated super-degrader Pseudomonas sp. DCα4: Postulated pathways, and attenuated ecotoxicological effects

Significant concentrations of emerging xenobiotics, like diclofenac (DCF), possessing severe irreversible eco-toxicological threats, has been detected in aquatic systems worldwide, raising the concerns. This present investigation is intended to explore an efficient solution to support the existing wastewater treatment policies to handle DCF contamination by bacteria-mediated biotransformation. DCF-tolerant bacterial strains were isolated from pharmaceutical wastewater and selected based on their non-virulence nature and degradation ability. Among those, Pseudomonas sp. DCα4 was found to be the most dominant DCF degrader exhibiting 99.82% removal of DCF confirmed by HPLC after optimization of temperature at 30.02 °C, pH at 6.9, inoculum of 4.94%, and time 68.02 h. The degradation kinetics exhibited the process of DCF degradation followed a first-order kinetics with k of 0.108/h and specific degradation rate of 0.013/h. Moreover, the enzyme activity study indicated predominant hydrolase activity in the DCF treatment broth of DCα4, implying hydrolysis as the main force behind DCF biotransformation. HRMS analysis confirmed the presence of 2-hydroxyphenylacetic acid, 1,3-dichloro,2-amino, 5-hydroxybenzene, and benzylacetic acid as major intermediates of DCF biodegradation indicating non-specific hydrolysis of DCF. Whole genome analysis of most related strains which were confirmed by near full 16S rRNA gene sequence homology study, predicted involvement of different N–C bond hydrolase producing genes like puud, atzF, astB, nit1, and nylB. The ecotoxicological study using Aliivibrio fischeri exhibited 47.51% bioluminescence inhibition by DCF-containing broth which was comparable to the same caused by 1 mg/mL of K2Cr2O7 whereas remediated broth exhibited only 0.51% inhibition implying reduction of the ecotoxic load caused by DCF contamination. Cost analysis revealed that possible integration of the process with existing ones would increase per litre expense by $0.45. These results indicated that the described process of DCF biodegradation using the super-degrader DCα4 would be an advancement of existing pharmaceutical wastewater treatment processes for DCF bioremediation.

Coupling pathway prediction and fluorescence spectroscopy to assess the impact of auxiliary substrates on micropollutant biodegradation.

Some bacteria can degrade organic micropollutants (OMPs) as primary carbon sources. Due to typically low OMP concentrations, these bacteria may benefit from supplemental assimilation of natural substrates present in the pool of dissolved organic matter (DOM). The biodegradability of such auxiliary substrates and the impacts on OMP removal are tightly linked to biotransformation pathways. Here, we aimed to elucidate the biodegradability and effect of different DOM constituents for the carbofuran degrader Novosphingobium sp. KN65.2, using a novel approach that combines pathway prediction, laboratory experiments,and fluorescence spectroscopy. Pathway prediction suggested that ring hydroxylation reactions catalysed by Rieske-type dioxygenases and flavin-dependent monooxygenases determine the transformability of the 11 aromatic compounds used as model DOM constituents. Our approach further identified two groups with distinct transformation mechanisms amongst the four growth-supporting compounds selected for mixed substrate biodegradation experiments with the pesticide carbofuran (Group 1: 4-hydroxybenzoic acid, 4-hydroxybenzaldehyde; Group 2: p-coumaric acid, ferulic acid). Carbofuran biodegradation kinetics were stable in the presence of both Group 1 and Group 2 auxiliary substrates. However, Group 2 substrates would be preferable for bioremediation processes, as they showed constant biodegradation kinetics under different experimental conditions (pre-growing KN65.2 on carbofuran vs. DOM constituent). Furthermore, Group 2 substrates were utilisable by KN65.2 in the presence of a competitor (Pseudomonas fluorescens sp. P17). Our study thus presents a simple and cost-efficient approach that reveals mechanistic insights into OMP-DOM biodegradation.

Biotechnological Potential of Oil-Tolerant Strains for Possible Use in Bioremediation

The release of oil into the environment represents a pervasive problem stemming from oil exploration, accidents, transportation and releases from landfills, storage facilities or industrial plants. Compared to conventional and costly techniques, bioremediation is an attractive and promising alternative, as it can selectively degrade pollution without affecting the natural features of the site and the flora and fauna living there. In this study, the isolation, identification and characterization of autochthonous bacterial strains from a crude oil-contaminated soil sample was carried out under batch conditions over a period of 28 days. The initial colony forming units value for bacteria was 1.15 × 109/g of soil. The results show that the activity of bacteria was highest at a pH of 7.25. Based on morphology, biochemical tests and an analysis of MALDI TOF, isolated autochthonous bacterial species were identified as Bacillus megaterium, Bacillus licheniformis, Bacillus cereus and Pseudomonas chlororaphis. Since allochthonous bacteria are not highly efficient in a new environment due to their low adaptability and competition with indigenous microorganisms, these autochthonous microorganisms play a pivotal role in enhancing the bioremediation process on an applicable, industrial scale. This advancement aligns with the principles of sustainable development and the green economy, as purified soil is suitable for rational reuse in the environment.

Anaerobic bioremediation of acid phosphogypsum stacks leachates: Assessment of leachate’s biochemical changes and microbial community dynamics

Phosphogypsum (PG) is the largest by-product of the phosphate industry. Nearly 300 M tons of PG are annually discarded, of which 58% is dry stacked. The exposure of PG stacks to rainwater and processed waters moisture creates hydraulic pressure, generating acidic PG leachates into nearby aquifer systems. Because of its elevated levels of sulfates, phosphorus (P) and metals, the PG water leachate can negatively affect the surrounding environments. This work investigates the effect of water activity on the PG leaching, by studying the effect of different PG:Water ratios on the leaching process, followed by the anaerobic bioremediation of PG leachate through biological sulfate removal activity (BSRA). This later involves using sulfate-reducing bacteria consortium within an anaerobic bioreactor, allowing a simultaneous monitoring of the leachate’s biochemical changes, impurities removal, and microbial community dynamics. The results determined the highest sulfates and impurities leaching from PG with a PG:Water ratio of 1:200 (w:v). Subsequently, the biological treatment of the leachate exhibited an efficient removal of sulfates (79%), P (99%) and chemical oxygen demand (93%), with a substantial decline in metal concentrations (Cd, As and Al by 99%, and Zn by 70%) from the leachate. Moreover, the acidity of the leachate was also neutralized through the BSRA process by increasing the pH from 4 to 7.52. Furthermore, the microbial community dynamics unveiled a significant correlation between the leachate’s biochemical changes and co-existence of specific sulfate-reducing bacteria within various bacterial phyla, including Desulfobacterota, Firmicutes, and Proteobacteria, allowing efficient and eco-friendly bioremediation process of PG leachate.