Bioremediation Potential Research Articles

Characterization of three rapidly growing novel Mycobacterium species with significant polycyclic aromatic hydrocarbon bioremediation potential.

Mycobacterium species exhibit high bioremediation potential for the degradation of polycyclic aromatic hydrocarbons (PAHs) that are significant environmental pollutants. In this study, three Gram-positive, rapidly growing strains (YC-RL4T, MB418T, and HX176T) were isolated from petroleum-contaminated soils and were classified as Mycobacterium within the family Mycobacteriaceae. Genomic average nucleotide identity (ANI; < 95%) and digital DNA-DNA hybridization (dDDH; < 70%) values relative to other Mycobacterium spp. indicated that the strains represented novel species. The morphological, physiological, and chemotaxonomic characteristics of the isolates also supported their affiliation with Mycobacterium and their delineation as novel species. The strains were identified as Mycobacterium adipatum sp. nov. (type strain YC-RL4T = CPCC 205684T = CGMCC 1.62027T), Mycobacterium deserti sp. nov. (type strain MB418T = CPCC 205710T = KCTC 49782T), and Mycobacterium hippophais sp. nov. (type strain HX176T = CPCC 205372T = KCTC 49413T). Genes encoding enzymes involved in PAH degradation and metal resistance were present in the genomes of all three strains. Specifically, genes encoding alpha subunits of aromatic ring-hydroxylating dioxygenases were encoded by the genomes. The genes were also identified as core genes in a pangenomic analysis of the three strains along with 70 phylogenetically related mycobacterial strains that were previously classified as Mycolicibacterium. Notably, strain YC-RL4T could not only utilize phthalates as their sole carbon source for growth, but also convert di-(2-ethylhexyl) phthalate into phthalic acid. These results indicated that strains YC-RL4T, MB418T, and HX176T were important resources with significant bioremediation potential in soils contaminated by PAHs and heavy metals.

Bioremediation potential of rhizosphere bacterial consortium in lead (Pb) contaminated rice plants

Abstract. Ubaidillah M, Thamrin N, Cahyani FI, Fitriyah D. 2023. Bioremediation potential of rhizosphere bacterial consortium in lead (Pb) contaminated rice plants. Biodiversitas 24: 4566-4571. Lead (Pb) is one of the toxic heavy metals detected in various chemical fertilizers and pesticides used in Indonesia. These chemicals can increase plant lead (Pb) accumulation and affect other organisms through its circulation with food chain. Excess amounts of Pb in soil may be remediated using different approaches such as bioremediation. Rhizosphere bacteria can be used as bioremediation agents to reduce Pb accumulation in plants and also increase plant growth. Actinomycetes, Azotobacter sp., Azospirillum sp., Rhizobium sp., Pseudomonas sp., Lactobacillus sp., Bacillus sp., and Streptomyces sp. are some of the several bacteria that can reduce lead (Pb) accumulation in plants by the ability to sequester Pb, change its oxidation state, or enable Pb to precipitate. This research was conducted to determine the ability of the rhizosphere bacterial consortium to prevent lead (Pb) accumulation in rice plants. This study confirmed that the application of rhizosphere bacterial consortium to rice plants contaminated with lead (Pb) can reduce the plant's lead (Pb) content by up to 45%. The use of a bacterial consortium did not significantly affect the growth parameters of the plant but increased root length by 41%, fresh weight by 32%, dry weight by 26%, and chlorophyll content by 25%, in rice plants contaminated with Pb.

Biosorption of Heavy Metal (Mn2+) by Thermophilic Bacterial Strains Isolated from Surya Kund Hot Spring, Yamunotri, Uttarakhand.

This investigation aimed to identify the bioremediation potential of Mn2+-resistant bacterial strains cultured from the Surya Kund hot spring, Yamunotri, Uttarakhand. In this study, eight heavy metal-resistant isolates belonging to two phyla, i.e., Firmicutes and Proteobacteria, were investigated for their Mn2+ biosorption potential. The metal tolerance potential of all the thermophilic bacterial strains was determined by MIC. Bioremediation assay of these metal-resistant strains was performed for Mn2+ through the live and dead biomass of the bacterial cell. The evaluation of the bioremediation rate of metal ions through bacteria was done by AAS. All the selected bacterial strains were evaluated with effective biosorption rates for Mn2+. Acinetobacter sp. LSN-10 (YII-1) has been showing the highest potential for the removal of Mn2+ in both live (41.202%) and dead biomass (64.721%) conditions. The bioremediation rate of dead biomass was observed quite higher in comparison to bioremediation through live bacterial cells in the maximum number of isolates. This study may provide a new eco-friendly and cost-effective approach to dealing with metal toxicity. However, further investigation is needed to identify the most effective applications and potential limitations of this method.

Detailed genomic and biochemical characterization and plant growth promoting properties of an arsenic-tolerant isolate of Bacillus pacificus from contaminated groundwater of West Bengal, India

In this study, arsenic tolerating bacteria Bacillus pacificus (AKS1a) was isolated from arsenic contaminated groundwater of Purbasthali, Purba Bardhaman, West Bengal, India and its bioremediation potential was preliminary screened. This multimetal resistant strain was able to grow against more than 20 mM arsenate and 10 mM arsenite salts. The genome was more than 5.16 Mb in length, with an average of around 35.2% GC content, bearing 5403 protein coding genes. Arsenic resistant genes like arsC, arsB, arsR, etc. were also identified. Rapid Annotation using Subsystem Technology (RAST) identified 328 subsystems within the genome. Presence of six Genomic Islands (GIs) and five phage virus genomic parts indicated its ecological adaptations to overcome environmental stresses. The production of about 415 μg mL−1 indole acetic acid (IAA), 258.0 μg mL−1 gibberellic acid (GA), and 183 μg mL−1 proline by the bacterium, along with nitrogen fixation ability under in-vitro conditions, indicate its plant growth promoting potential. This was further confirmed through rice seedling growth enhancement under arsenic stress. Beside arsenite oxidation to arsenate, its arsenic adsorption property was confirmed through X-ray Fluorescence spectroscopy (XRF), Fourier Transform Infrared spectroscopy (FTIR), and Energy Dispersive X-ray spectroscopic (EDS) analysis. Genomic comparisons among 25 different strains of B. pacificus showed that there are tremendous genetic differences in respect to their accessory genome content. In future, this strain can be applied as biofertilizer or biostimulant for improving rice plant growth.

Synthesis, characterization, and reusability of novel nanobiocomposite of endophytic fungus Aspergillus flavus and magnetic nanoparticles (Fe3O4) with dye bioremediation potential

The incorrect disposal of textile dyes, such as Reactive Black 5 (RB5), causes several problems for living beings and the quality of the environment. Nanobiocomposites (NBC) produced from endophytic fungi (potentially remediation dyes-agents) and magnetic nanoparticles have high biotechnological potential due to their superparamagnetic behavior, which would allow their recovery through the magnetic field after the bioremediation process. This work aimed to obtain a new nanobiocomposite from the interaction of magnetite nanoparticles (Fe3O4) with the endophyte Aspergillus flavus (Af-CL-7) to evaluate its bioremediation capacity and to reduce the toxicity of RB5 and its reuse. Before obtaining the NBC, Af-CL-7 showed discoloration of RB5 and it was tolerant to all tested concentrations of this dye. The discovery of the nanobiocomposite textile dye bioremediator product presents a significant environmental advantage by addressing the issue of water pollution caused by textile dyes. The NBC called Af-Fe3O4 was successfully obtained with the magnetized endophyte, and their magnetic properties were verified by VSM analysis and by action of magnetic fields generated by Nd-Fe-B magnets SEM analyzes showed that the nanoparticles did not cause any damage to the hypha morphology, and TEM analyzes confirmed the presence of nanoparticles in the fungus wall and also inside the cell. The NBC Af-Fe3O4 and Af-CL-7 showed, respectively, 96.1% and 92.2% of RB5 discoloration in the first use, 91.1% e 86.2% of discoloration in the validation test, and 89.0% in NBC reuse. In the toxicological bioassay with Lactuca sativa seeds, NBC showed a positive reduction in the toxicity of RB5 after treatment, allowing the hypocotyl growth to be statistically similar to the control with water. Thus, we highlight the promising obtaining process of NBC that could be applied in bioremediation of contaminated waters, wherein the industrial economic cost will depend on the fermentation efficiency, biomass production and nanoparticle synthesis.

Exploring a unique water ecosystem under long-term exposure to hexavalent chromium – An in situ study of natural diatom (Bacillariophyceae) communities

This paper reports the third in a series of three studies of a unique aquatic phytobial consortium that developed in a polluted ditch situated near an old chromium waste landfill. The ditch is a specific ecological niche having increased loads of several chemical compounds, including extreme hexavalent chromium concentrations up to two thousand times the allowed limit (0.02 mg dm−3 in Poland) in the more polluted section B; the moderate concentrations in section A are twice the limit. We focus on the microscopic algae group of diatoms, one of the most important components of the phytobial consortium, and continue our novel attempt to analyze the bioremediation potential of the entire consortium under those environmental conditions. We used numerical methods to analyze differences in diatom biodiversity between sections A and B, and assessed the relations between diatoms and selected water chemistry properties, including hexavalent chromium, chlorides and sulphates, the latter two known to positively influence the resistance of algae to the impact of hexavalent chromium. We noted 37 diatom taxa in section A of the ditch and 30 in section B. The most frequently observed diatoms were cosmopolitan taxa and/or characteristic taxa of saline waters. Sulphates were the most important factor influencing the diatom composition in the ditch, explaining 52% of the total variability, followed by chlorides (30%) and hexavalent chromium (9%). Gomphonema acuminatum, Melosira varians and Nitzschia frustulum var. frustulum were found to be most resistant to hexavalent chromium and were selected for further experimental studies on their biotechnological usefulness.

Evaluation of Bioremediation Potentiality of Bacillus mojavensis Isolated from Wastewater for the Elimination of Reactive Yellow 145 and Methyl Orange.

Textile industry waste has become one of the largest polluters in the world. In recent years, there has been a growing awareness of the need for sustainable and eco-friendly practices for the treatment of dye-laden effluents. Overall, this study highlights the potential of bioremediation as a sustainable solution for wastewater treatment. The Bacillus mojavensis isolated from wastewater and identified using 16S rRNA degraded reactive yellow 145 and methyl orange in 36h of incubation, this decolorization was affected by pH, temperature, dye concentration, glucose concentration, source of nitrogen, type of dye, and agitation. Our study found that the optimal conditions for total decolorization of dyes were achieved by incubating B. mojavensis at 46°C, pH 9, with 1g/L of glucose and 2g/L of peptone. The azoreductase activity, FT-IR analysis, and UV-visible spectrum before and after total decolorization indicated that it was a dye degradation rather than biosorption in surface Celle. In addition, the study of phytotoxicity show the metabolites of degradation are not phytotoxic in Lens esculenta seeds. In conclusion, our results suggest the use of this bacterium as an environmentally friendly and also cost-effective method, making it an attractive option for industries looking to reduce their environmental impact.

Bioremediation Potential of Cr(VI) by Lysinibacillus cavernae CR-2 Isolated from Chromite-Polluted Soil: A Promising Approach for Cr(VI) Detoxification

The present study focuses on an efficient Cr(VI)-reducing bacterial strain (CR-2) isolated from an abandoned chromate plant in Qinghai Province, China. CR-2 was confirmed as Lysinibacillus cavernae using 16S rRNA gene sequencing. CR-2 could survive at 500 mg L−1 Cr(VI) and effectively reduce Cr(VI) at concentrations of <50 mg L−1, a pH of 5–9, a temperature of 20–40 °C, and a salinity of 5–15 g L−1. According to the Box–Behnken experimental design, the maximum Cr(VI) removal efficiency by L. cavernae CR-2 was 76.21% under optimum conditions, which comprised a pH of 6.68, a temperature of 28.90 °C, and a salinity of 9.85 g L−1. With regard to Cr(VI) reduction mediated by L. cavernae CR-2, enhancement in efficiency was observed in the presence of Cu2+ and Ca2+, while significant inhibition in the reduction capacity occurred upon exposure to Mg2+, Ba2+, Ni2+, Pb2+, or Cd2+. Moreover, L. cavernae CR-2 tends to use glucose as an electron donor for the reduction of Cr(VI). Results of cell fraction separation and degeneration indicated that the Cr(VI) removal was primarily due to the reduction of Cr(VI) via chromium reductase in the cytoplasm. In addition, bioanalysis of L. cavernae CR-2 by SEM-EDS and TEM-EDS suggested that Cr was distributed both on the surface and in the cell cytoplasm. FT-IR analyses established that multiple functional groups (hydroxyl, carbonyl, amide, amino, and aldehyde groups) participated in the Cr(VI) biosorption on the cell surface. XPS and HPLC also showed that the Cr(III) end-products could be present as Cr(III) hydroxides or as organic–Cr(III) complexes. This study yields insights into the Cr(VI) bioreduction mechanism of L. cavernae CR-2.

Efficient biodegradation of the recalcitrant organochlorine pesticide chlordecone under methanogenic conditions

Anaerobic digestion (AD) has long been studied as an effective environmental and economic strategy for treating matrices contaminated with recalcitrant pollutants. In the present work, we investigated the bioremediation potential of AD on organic waste contaminated with chlordecone (CLD), an organochlorine pesticide extensively used in the French West Indies and classified among the most persistent organic pollutants. Digestates from animal and plant origins were supplemented with CLD and incubated under methanogenic conditions for over 40 days. The redox potential and pH monitoring showed that methanogenic conditions were preserved during the entire incubation period despite the presence of CLD. In addition, the comparison of the total biogas generated from digestates with and without CLD demonstrated no adverse effects of CLD on biogas production. For the first time, a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction method, followed by GC–MS and LC-HRMS analyses, was developed to quantify CLD and its main known transformation products (TPs) in AD experiments. A decrease in CLD concentrations was evident to a greater extent under thermophilic conditions (55 °C) compared to mesophilic conditions (37.5 °C) (CLD removal of 85 % and 42 %, respectively, after 40 days of incubation). CLD degradation was confirmed by the detection and quantification of several TPs: 10-monohydroCLD (A1), two dihydroCLDs different from 2,8-dihydroCLD (A3), pentachloroindene (B1), tetrachloroindenes (B2, B3/B4), tetra- and tri-chloroindenecarboxylic acids (C1/C2, C3/C4). Determining TPs concentrations using the QuEChERS method provided an overview of CLD fate in AD. Overall, these results reveal that AD processes can efficiently degrade CLD into several TPs from A, B, and C families while maintaining satisfactory biogas production. They pave the way to developing a scaled-up AD process capable of treating CLD-contaminated organic wastes produced by farming, thus stopping any further transfer of CLD.

Systematic screening strategy for fungal laccase activity of endophytes from Otoba gracilipes with bioremediation potential

Fungal laccases are promising for biotechnological applications, including bioremediation and dye biotransformation, due to their high redox potential and broad substrate specificity. However, current bioprospecting methods for identifying laccase-producing fungi can be challenging and time-consuming. For early detection, it was developed a three-step, multi-criteria weighting system that evaluates fungal strains based on: First, the biotransformation capacity of three dyes (i.e., Congo red, brilliant blue G-250, and malachite green), at three different pH values, and with a relative weighting supported for the redox potential of each colorant. The relative decolorization coefficient (RDC), used as th2e first classification criterion, expressed their potential performance. Second, under the same conditions, laccase activity was estimated by observing the different degrees of oxidation of a given substrate. The selection criterion was the relative oxidation coefficient (ROC). Finally, laccase activity was quantified in submerged fermentations using three inducers (i.e., loofah sponge, Tween 80, and veratyl alcohol). This multicriteria screening strategy evaluated sixteen isolated endophytic fungal strains from Otoba gracilipes. The system identified Beltraniopsis sp. ET-17 (at pH values of 5.00 and 5.50) as a promising strain for dye biotransformation, and Phlebia floridensis as the best laccase producer, achieving a high activity of 116 μmol min−1 L−1 with loofah sponge as an inducer. In-vitro testing confirmed the efficacy of P. floridensis, with 53.61 % decolorization of a dye mixture (brilliant blue-Congo red. ratio 1:1) after 15 days of incubation. Thus, with the proposed screening strategy it was possible to highlight two species of interest at an early bioprospecting stage on a Colombian native tree poorly explored.

Unveiling the draft genome sequence of diesel-degrading Paenibacillus sp. strain d9, a surfactant producer isolated from diesel-contaminated soil

Introduction: Gram-positive bacteria, particularly Bacillus and Paenibacillus spp., have gained significant attention for their potential in environmental bioremediation (biosurfactant production) and diverse biotechnological applications. Among these, Paenibacillus sp. D9, isolated from oil-contaminated soil, has shown diesel and engine oil degradation capabilities and biosurfactant production. However, its role in alkane degradation remains unexplored. Methodology and Result: To shed light on its unique attributes, we conducted whole-genome sequencing of Paenibacillus sp. D9 using the Illumina HiSeq 2000 platform. The draft genome comprised 56 contigs and 7 scaffolds, with a size of 5,645,302 bp at 157.94× coverage and a G + C content of 58.13%. A total of 9,950 Coding Sequences (CDSs) were predicted, and functional annotation revealed 3,283 (43.19%) and 3,155 (58.8%) putative genes based on Bacterial Annotation System (BASys) and Rapid Annotation using the Subsystems Technology (RAST) subsystem categorization, respectively. Furthermore, 93 tRNA and 23 rRNA genes were identified. Conclusion: This genome announcement provides valuable insights into the genetic potential of Paenibacillus sp. D9 and paves the way for future research in its biotechnological applications.

Mechanisms of Mucor sp. CM3 isolated from the aquatic macrophyte Eichhornia crassipes (Mart.) Solms to increase cadmium bioremediation.

Bioremediation of toxic metals is a feasible and low-cost remediation tool to reduce metal contamination. Plant-fungus interactions can improve this technique. Eichhornia crassipes (Mart.) Solms is a macrophyte reported to bioremediate contaminated water. Thus, the present study aimed to isolate endophytic fungi from E. crassipes, select a highly cadmium (Cd) tolerant isolate and evaluate its bioremediation potential. This was evaluated by (1) the fungus tolerance and capacity to accumulate Cd; (2) Cd effects on cell morphology (using SEM and TEM) and on the fungal antioxidant defense system, as well as (3) the effect on model plant Solanum lycopersicum L. cultivar Calabash Rouge, inoculated with the endophyte fungus and exposed to Cd. Our results selected the endophyte Mucor sp. CM3, which was able to tolerate up to 1000g/L of Cd and to accumulate 900mg of Cd/g of biomass. Significant changes in Mucor sp. CM3 morphology were observed when exposed to high Cd concentrations, retaining this metal both in its cytoplasm and in its cell wall, which may be linked to detoxification and metal sequestration mechanisms related to the formation of Cd-GSH complexes. In addition, Cd stress induced the activation of all tested antioxidant enzymes - superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) - in this endophytic fungus. Moreover, when inoculated in tomato plants, this fungus promoted plant growth (in treatments without Cd) and induced an increased metal translocation to plant shoot, showing its potential to increase metal bioremediation. Therefore, this study indicates that the isolated endophyte Mucor sp. CM3 can be applied as a tool in different plant conditions, improving plant bioremediation and reducing the environmental damage caused by Cd, while also promoting plant growth in the absence of contaminants.

Heavy Metal Bioremediation Potential of Autochthonous Lactic Acid Bacteria for Use in Edible Leafy Vegetables

Heavy metals are well-known as destructive environmental pollutants that cause serious health problems. The use of bacterial biological biosorption has been proposed as a practical and environmentally friendly solution for the removal of heavy metals. The current study was conducted in in vitro and in situ conditions. Initially, seven strains of lactic acid bacteria with probiotic properties (Lacticaseibacillus casei, Lacticaseibacillus rhamnosus, Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Enterococcus faecium, Lactobacillus helveticus, and Lactobacillus acidophilus) were screened for their ability to bind cadmium, lead, and nickel in an aqueous solution. Three of the potent probiotic strains that showed the highest biosorption efficiency at this stage were selected for further analysis. The effect of these bacteria mixed at a ratio of 1 : 1 : 1 on the removal of toxic metals in fresh leaves of edible vegetables including coriander, leek, and parsley was evaluated within 15 and 30 minutes. During in vitro analysis, the sorption percentage of Pb and Cd appeared higher than 99% during 15 minutes of initial contact, while increasing contact time (30 minutes) had no significant effect on the removal of these metals. While during in situ analysis, Ni sorption by the selected lactic acid bacteria (LAB) isolates was significantly enhanced with increasing contact time, such that the highest biosorption rate was recorded in coriander leaves at 30 minutes (91.15%). Overall, E. faecium showed the highest sorption of Pb, Cd, and Ni (79.75 ± 0.11, 75.28 ± 0.05, and 83.99 ± 0.10%), respectively. The combination of three bacterial strains had a synergistic effect on the toxic metal binding capacity compared to the single state of these bacteria, and the biosorption level increased to 99.94 ± 0.02, 99.91 ± 0.01, and 93.75 ± 0.04%, respectively. Scanning electron microscopic (SEM) observations and energy dispersive X-ray (EDX) analysis confirmed that the majority of Pb, Cd, and Ni were bound to the surface of the bacterial cell.

Eco-friendly Biodegradation of Hydrocarbons Compounds from Crude Oily Wastewater Using PVA/Alginate/Clay Composite Hydrogels

Immobilized microorganisms especially bacteria are most used rather than free cells to be protected from the environmental conditions when being used for the bioremediation of environmental pollutants. Herein, two marine’s bacterial isolates were tested for their ability to decompose crude oil. The optimum conditions for effective bacterial degradation e.g., pH, temperature, and inoculum size were investigated. PVA-alginate-clay composite hydrogel beads with different types of incorporated mineral clays were prepared and tested as bacterial carrier for potential bioremediation. Synthesized composite hydrogels were physico-chemically characterized by FTIR, SEM, and thermal analyses. Results showed that, embedded degrading bacteria in PVA-alginate beads recorded degradation rates as 74 and 66.6% for both tested bacterial isolates (S and R) compared to 61.2 and 53% degradation rates by free cells, respectively. Where, attapulgite clay-containing beads recorded maximum degradation% as 78.8 and 75% for both bacterial isolates, when added to immobilization matrices and these percentages could be enhanced under optimal conditions. The 16S rRNA gene of the two marine oils degrading bacterial isolates were amplified and sequenced, where both isolates were identified as Pseudomonas stutzeri and Rhodococcus qingshengii with submitted accession numbers of ON908963 and ON908962, respectively. These results are referring to the ability of using both tested isolates for crude oil bioremediation process and embedded them into PVA-alginate-clay beads as hydrogel carrier under the optimum conditions.

Comparative Assessment of Biodegradability Potential of Pseudomonas putida and Bacillus amyloliquefaciens on Oil Spill Dispersant (Aquabreak and Teepol) in Freshwater

To compare and assessment of Biodegradability Potential of Pseudomonas putida and Bacillus amyloliquefaciens on oil spill dispersant (Aquabreak and Teepol) in Freshwater. Fresh water sample were collected from Biara, Gokana L.G.A, and were transported to the Microbiology Laboratory of Rivers State University, Port Harcourt, Nigeria for analyses while Oil spill dispersant (OSD/Aquabreak) was purchased from Barker and Hughes, all in Rivers state. Nine experimental set up were carried out using Bacillus and Pseudomonas species as the bio-augmenting organism. Controls were made without organisms. Its bioremediation potential on the pollutants and two types of test organisms were monitored for 28 days at an interval of 7day period. The setup was aerated twice a week to provide more oxygen for the organisms to thrive. Analysis of samples were carried out using standard analytical procedures. The resultsphysiochemical property of the water shows that as follows: pH 6.5, Temperature 30.0 ºC, Electric conductivity 15 µs/cm, Total dissolved solid 7 mg/l ,Chlorine 0.1 mg/l, Bromine 0.2 mg/l, Salinity (0.01 mg/l), Dissolved oxygen 1.5 mg/l , Biological Oxygen Demand 0.3 mg/l, Nitrate 0.01 mg/l, Sulphate 4.18 mg/l Phosphate 0.10 to 1.5mg/l, Total Hydrocarbon content 24mg/l. Percentage (%) Ultimate biodegradability of the two oil spill dispersant OSD/teepol and OSD/aquabreak revealed that control set-up recorded the 79.3 and 86.7 % , bioremediation set-up augmented with Bacillus amyloliquefaciens recorded 93.7 and 99.1% while the set-up augmented with P. putida had 98.0 and 94.7% respectively . It was observed that P. putida degrade Teepol than Bacillus amyloliquefaciens while aquabreak is more degraded by Bacillus amyloliquefaciens than P. putida. Nevertheless both dispersant shown high level of degradability by the test organisms. Therefore It is recommended that oil companies and government parastatals carrying out remediation in the Niger Delta should be encouraged and OSD/Teepol and OSD/aqubreak due to their high biodegradation potential.

Cold adapted Pseudomonas: ecology to biotechnology.

The cold adapted microorganisms, psychrophiles/psychrotolerants, go through several modifications at cellular and biochemical levels to alleviate the influence of low temperature stress conditions. The low temperature environments depend on these cold adapted microorganisms for various ecological processes. The ability of the microorganisms to function in cold environments depends on the strategies directly associated with cell metabolism, physicochemical constrains, and stress factors. Pseudomonas is one among such group of microorganisms which is predominant in cold environments with a wide range of ecological and biotechnological applications. Bioformulations of Pseudomonas spp., possessing plant growth promotion and biocontrol abilities for application under low temperature environments, are well documented. Further, recent advances in high throughput sequencing provide essential information regarding the prevalence of Pseudomonas in rhizospheres and their role in plant health. Cold adapted species of Pseudomonas are also getting recognition for their potential in biodegradation and bioremediation of environmental contaminants. Production of enzymes and bioactive compounds (primarily as an adaptation mechanism) gives way to their applications in various industries. Exopolysaccharides and various biotechnologically important enzymes, produced by cold adapted species of Pseudomonas, are making their way in food, textiles, and pharmaceuticals. The present review, therefore, aims to summarize the functional versatility of Pseudomonas with particular reference to its peculiarities along with the ecological and biotechnological applications.

Heterologous expression, purification, and characterization of thermo- and alkali-tolerant laccase-like multicopper oxidase from Bacillus mojavensis TH309 and determination of its antibiotic removal potential.

Laccases or laccase-like multicopper oxidases have great potential in bioremediation to oxidase phenolic or non-phenolic substrates. However, their inability to maintain stability in harsh environmental conditions and against non-substrate compounds is one of the main reasons for their limited use. The gene (mco) encoding multicopper oxidase from Bacillus mojavensis TH309 were cloned into pET14b( +), expressed in Escherichia coli, and purified as histidine tagged enzyme (BmLMCO). The molecular weight of the enzyme was about 60kDa. The enzyme exhibited laccase-like activity toward 2,6-dimethoxyphenol (2,6-DMP), syringaldazine (SGZ), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The highest enzyme activity was recorded at 80°C and pH 8. BmLMCO showed a half-life of ~ 305, 99, 50, 46, 36, and 20min at 40, 50, 60, 70, 80, and 90°C, respectively. It retained more than 60% of its activity after pre-incubation in the range of pH 5-12 for 60min. The enzyme activity significantly increased in the presence of 1mM of Cu2+. Moreover, BmLMCO tolerated various chemicals and showed excellent compatibility with organic solvents. The Michaelis constant (Km) and the maximum velocity (Vmax) values of BmLMCO were 0.98mM and 93.45µmol/min, respectively, with 2,6-DMP as the substrate. BmLMCO reduced the antibacterial activity of cefprozil, gentamycin, and erythromycin by 72.3 ± 1.5%, 79.6 ± 6.4%, and 19.7 ± 4.1%, respectively. This is the first revealing shows the recombinant production of laccase-like multicopper oxidase from any B. mojavensis strains, its biochemical properties, and potential for use in bioremediation.

Isolation, Identification and Molecular Characterization of Indigenous Bacterial Isolates from Textile Effluent and Contaminated Soil using 16s rRNA Sequencing

Textile industry effluent poses a serious environmental threat. Many physical and chemical methods for treating wastewater have been used, but due to high operating costs, a suitable alternative is required. As a result, the study focuses on the use of biological organisms with bioremediation potential which leads to the development of cost-effective and nontoxic methods. The present study focuses on the isolation of possible bacterial isolates from textile effluent contaminated soil and effluent. A total of four bacterial isolates were successfully isolated, three from textile industry effluent contaminated soil and one from textile industry effluent. Based on the results of morphological, biochemical and molecular datasets, the current study identified bacterial isolates belonging to three genera: Brevibacillus, Achromobacter and Pseudomonas. The 16S rRNA sequence technique was used to characterize and identify the bacterial isolates. The isolates were submitted to GenBank like Achromobacter xylosoxidans KUESCCHK-6, Pseudomonas aeruginosa KUESCCHK-5, Achromobacter insuavis KUESCCHK-7 and Brevibacillus panacihumi KUESCCHK-8 with accession numbers OM475749, OM475764, OL797980 and OM475766 respectively. Bacteria can survive in contaminated environments because of their metabolic ability to use available resources and ability to find a suitable niche.

Biodegradation of phthalic acid esters (PAEs) by Bacillus sp. LUNF1 and characterization of a novel hydrolase capable of catalyzing PAEs

Phthalic acid esters (PAEs), the universal plasticizers, have widely entered the environment and cause serious contamination, potentially threatening human health. Furthermore, PAEs are highly resistant to degradation due to their hydrophobicity. In the present study, a PAE degrader, Bacillus sp. LUNF1, was isolated from sewage sludge. Strain LUNF1 completely removed dibutyl phthalate (DBP) from wastewater, demonstrating its great potential for PAE bioremediation. The genetic mechanism underlying PAE degradation by strain LUNF1 was elucidated by identification of the novel PAE hydrolase DphBL1 belonging to family VII. The hydrolase was overexpressed in E. coli BL21(DE3) and purified by affinity chromatography. It displayed high hydrolytic efficiency toward DBP at 10–50 °C and pH 5.0–9.0. Importantly, DphBL1 maintained its stability in the presence of β-mercaptoethanol (β-ME), phenylmethylsulphonyl fluoride (PMSF) and various metal ions, which did not significantly inhibit DphBL1. It was also found that the catalytic triad (Ser190-His395-Glu306), oxygen hole (Gly107-Ala108) and other residues (Phe310, Ile358, Phe359, Leu309 and Leu269) were involved in interacting DBP. DphBL1 mutants with significantly reduced activity confirmed the essential role of these active residues and revealed the catalytic mechanism of DphBL1. These results will support structural modification of PAE hydrolases to improve catalytic efficiency in bioremediation, and promote the development of efficient strategies for PAE remediation in the environment.

Rhodotorula mucilaginosa YR29 is able to accumulate Pb2+ in vacuoles: a yeast with bioremediation potential.

Microorganisms showed unique mechanisms to resist and detoxify harmful metals in response to pollution. This study shows the relationship between presence of heavy metals and plant growth regulator compounds. Additionally, the responses of Rhodotorula mucilaginosa YR29 isolated from the rhizosphere of Prosopis sp. growing in a polluted mine jal in Mexico are presented. This research carries out a phenotypic characterization of R. mucilaginosa to identify response mechanisms to metals and confirm its potential as a bioremediation agent. Firstly, Plant Growth-Promoting (PGP) compounds were assayed using the Chrome Azurol S (CAS) medium and the Salkowski method. In addition, to clarify its heavy metal tolerance mechanisms, several techniques were performed, such as optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) supplemented with assorted detectors. Scanning transmission electron microscopy (STEM) was used for elementary mapping of the cell. Finally, yeast viability after all treatments was confirmed by confocal laser scanning microscopy (CLSM). The results have suggested that R. mucilaginosa could be a PGP yeast capable of triggering Pb2+ biosorption (representing 22.93% of the total cell surface area, the heavy metal is encapsulated between the cell wall and the microcapsule), and Pb2+ bioaccumulation (representing 11% of the total weight located in the vacuole). Based on these results, R. mucilaginosa as a bioremediation agent and its wide range of useful mechanisms for ecological purposes are highlighted.