Green titanium dioxide (TiO2 ) nanoparticles assisted biodegradation of anthracene employing Serratia quinivorans HP5.

The anthracene biodegradation potential of Serratia quinivorans HP5 was studied under a controlled laboratory environment. The green TiO2 nanoparticles (NPs) synthesized from Paenibacillus sp. HD1PAH was used to accelerate the biodegradation process. The synergistic application of TiO2 NPs and S. quinivorans HP5 resulted in a reduction of anthracene concentration by 1.2 folds in liquid-medium and 1.5 folds in contaminated soil. Gas-chromatography and mass-spectrometric investigation showed the production of four anthracene derivatives, namely 1,2-anthracene dihydrodiol, 6,7-benzocoumarin, anthrone, and 9,10-anthraquinoneat the termination of experimental periods. Furthermore, bacterial biomass increased by 23.3 folds in the presence of TiO2 NPs, and overall soil enzyme activities were enhanced by 4.2 folds in the treated samples. In addition, there was a negative correlation observed between the biomass of S. quinivorans HP5 and the concentrations of anthracene, suggesting the involvement of bacterium in anthracene biodegradation processes. The degradation pathway of anthracene revealed its transformation into the less toxic compound 9,10-anthraquinone. Overall, this study elucidates a novel biodegradation pathway for anthracene and highlights the potential of nano-assisted bacterial remediation as a promising approach for environmental cleanup.

Metals stress on soil enzyme activities and herbs defense in the vicinity of high traffic roadways.

This study has investigated the impact of vehicle sourced heavy metals (HMs) on soil enzyme activities and plants in and around high traffic roadways near the metropolitan area. In detail, the defense response against HM pollution was studied by considering the commonly available herbs around the roadside area namely Alternanthera paronychioides, Ageratum conyzoides, Spilanthes acmella, and Parthenium hysterophorus. The study reported that the HM concentrations such as Cu, Ni, Zn, Mn, and Cr were observed in the range of 6.05 ± 0.1 to 309 ± 0.5 mg/kg in roadside soil and 5.2 ± 0.1to 451 ± 4.2 mg/kg in the herbs collected from roadside area. The soil enzyme (urease, dehydrogenase, amylase, catalase, peroxidase, and polyphenol oxidase) activities decreased by 22.56 to 77.84% in roadside soil and lower IC50 values were observed for DPPH (2.32-4.67) and H2O2 (1.59-2.15) free radical scavenging activities in plants collected from roadside area. The flavonoid and phenolic content in plants collected from the roadside area ranges from 12.65 ± 0.2 to 15.75 ± 0.3 mg quercitin/g and 0.61 ± 0.04 to 1.16 ± 0.1 mg gallic acid/g respectively while in plant collected from the control areas ranges from 7.96 ± 0.1 to 11.24 ± 0.05 and 0.47 ± 0.01 to 0.61 ± 0.1. In addition, the contamination factor (CF) (1.53-11.92) and geo-accumulation index (Igeo) (0.031-2.99) in soil and bioaccumulation factor (BAF) (0.72-2.73) of Cu, Ni, Zn, Mn, and Crin plants indicated that the soil and plants growing along the highway were heavily contaminated with HM. Finally, Pearson correlation matrix confirmed the inhibition effect of HM on soil enzymatic activities and enzymatic defense of plants in response to the HM stress.

Comparative investigation on synergistic changes in enzyme activities during vermicomposting of cereal grain processing industry sludge employing three epigeic earthworm species.

The management of cereal grain processing industry sludge through vermicomposting is an emerging prospect for researchers interested in the green economy. This work is designed to enumerate the enzymatic influence of three epigeic earthworm species - Eisenia fetida, Eudrilus eugeniae, and Perionyx excavatus on the industrial sludge. The vermicomposting experiment was conducted in plastic pots by blending the waste materials with 5% cow dung. The dynamics in activities of cellulase, amylase, invertase, phosphatase, protease, dehydrogenase, and urease were studied on 15 days intervals till the harvesting period. The periodical observations confirmed that the enzyme activities (in terms of µg reducing sugar/g/hr) of cellulase (26.45-128.09) amylase (205.43-878.96), invertase (105.32-841.65), phosphatase (85.29-435.54), protease (64.21-359.47), dehydrogenase (111.17-587.72), and urease (94.16-476.71) was low in the first 15 days of the vermicomposting experiment followed by a sharp increase in the next 45 days accompanied by a steady decline until the harvesting is carried out. Emerging statistical tools such as principal component analysis were employed to study the synergistic deviations of the enzymes during the vermicomposting process. The results confirmed that the enzyme activity efficiently influences the bio-oxidation of industrial waste at an individual level as well as synergistic level thereby allowing the vermicompost to mature much before the appearance of any physical symptoms on the surface of the vermireactors.

Vermiremediation of heavy metals (HMs)-contaminated agricultural land: synergistic changes in soil enzyme activities and earthworm's growth parameters.

In this investigation the heavy metals (Cu, Zn, Mn, Cr and Ni) remediation potential of Eisenia fetida was studied in the crude oil polluted soil. The potential of E. fetida was evaluated based on the decrease in concentrations of Cu, Zn, Mn, Cr and Ni, and improvement in the soil enzyme activities at the end of 90 days of experimental trials. Moreover, soil health quality, inter-relationship between the enzyme activities and the growth parameters of E. fetida and synergistic relation among the enzyme activities were also evaluated through G-Mean and T-QSI indices, chord plot analysis and principal component analysis (PCA) to confirm the performance of E. fetida during vermiremediation. The results revealed that the soil treated with E. fetida showed a reduction in the concentration of Cu, Zn, Mn, Cr and Ni by 17.4% 19.45%, 9.44%, 23.8% and 9.6% respectively by end of the experimental trials. The cellulase, amylase, polyphenol oxidase, peroxidase, urease, dehydrogenase and catalase activities in the E. fetida-treated soil were enhanced by 89.83%, 99.17%, 142%, 109.9%, 92.9%, 694.3% and 274.5% respectively. The results of SEM-EDS revealed enhancement in the O, K, Na, Mg and P content by 62.36%, 96.2%, 97.9%, 93.7% and 98.2% respectively by the end of the experimental trial. The G-Mean and T-QSI indices also confirmed the improvement in soil enzyme activities thereby indicating the positive influence of E. fetida on soil decontamination process. The chord plot indicated the interrelationship between the earthworm's growth parameters and enzyme activities of the soil as indicated by the high linkage between the nodes. Finally, the PCA confirmed the negative effect of the heavy metals on the soil enzyme activities and synergistic interrelationship between the enzyme activities during the vermiremediation process. Thus, this study demonstrated the changes in the soil enzyme activities and their interconnected influences during vermiremediation of crude oil sourced heavy metals from polluted soil.

Anthracene removal potential of green synthesized titanium dioxide nanoparticles (TiO2-NPs) and Alcaligenes faecalis HP8 from contaminated soil.

Anthracene biodegradation potential has been studied in liquid culture and soil microcosm environment by employing green synthesized TiO2 nanoparticles (NPs) and Alcaligenes faecalis HP8. The bacterium was isolated from crude oil contaminated soil, while TiO2 nanoparticles were synthesized using Paenibacillus sp. HD1PAH and Cyperus brevifolius which have PAHs remediation abilities. The dual application of TiO2 nanoparticles and Alcaligenes faecalis HP8 decreases anthracene concentration up to 21.3% in liquid at the end of 7 days and 37.9% in the soil treatments after completion of 30 days. Besides, the GC-MS analysis revealed production of five metabolites including 1,2-anthracenedihydrodiol; 6,7-benzocoumarin; 3-hydroxy-2-naphthoic acid; salicylic acid and 9,10-anthraquinone at different time interval of the treatments. Anthracene degradation pathway confirms the breakdown of three ring anthracene to one ring salicylic acid. Additionally, soil dehydrogenase, urease, alkaline phosphatase, catalase and amylase activities increased up to 4.09 folds, 8.6 folds, 4.4 folds, 3.6 folds and 2.1 folds respectively after the combined treatments of TiO2 nanoparticles and Alcaligenes faecalis HP8. The bacterial biomass and residual anthracene concentration were found to be negatively correlated. Finally, the study brings into light a novel anthracene biodegradation pathway and provides a new dimension in nano assisted bacterial remediation.

Crude oil associated heavy metals (HMs) contamination in agricultural land: Understanding risk factors and changes in soil biological properties.

Ecological and human risks of crude oil associated heavy metals (HMs) in the contaminated agricultural lands were evaluated employing different indices. The indices that were employed includes enrichment factor (EF), contamination factor (Cf),pollution load index (PLI), geo-accumulation index (Igeo), ecological risk index (ERI), contamination degree (Cd), Nemerow's pollution index (PN), exposure factor (ExF), hazard quotient (HQ) and hazard index (HI). Besides, the adverse effects of crude oil associated HMs on the soil biological properties were also analyzed. The results of Cf and EF were found consistent with each other showing the HMs in the decreasing order of contamination as Mn > Zn > Cr > Ni > Cu. The Igeo and ERI fall in the grade (Igeo>5) and (ERI ≥40) respectively. The results of PLI, Cd, PN and ExF values clearly indicate a high environmental risk of crude oil-associated HMs. The results of the human health risks assessment revealed the maximum level of HMs enters the body via ingestion. There were significant(p < 0.05) decreases (5.7-15.5 folds) in the activities of cellulase (0.194 ± 0.02-0.998 ± 0.1), phosphatase (0.173 ± 0.3-0.612 ± 1.5), catalase (0.328 ± 0.3-2.036 ± 1.5), urease (0.44 ± 0.3-1.80 ± 1.2), dehydrogenase (0.321 ± 0.2-0.776 ± 0.7),polyphenol oxidase (0.21 ± 0.5-0.89 ± 2.5)and peroxidase (0.13 ± 0.4-0.53 ± 1.03)in crude oil-contaminated soil. The Pearson's correlation confirmed the significant negative impact of HMs on the soil's biological properties.

Ecological risk assessment of priority PAHs pollutants in crude oil contaminated soil and its impacts on soil biological properties.

Polycyclic aromatic hydrocarbons (PAHs) are one of the major toxic constituents of crude oil and therefore, an understanding on PAHs associated risks and their relationship with soil biological parameters are necessary for adopting effective risk-based and site specific remediation strategies in the contaminated soil. Here, risks evaluation of eight detected PAHs in terms of toxic equivalent concentration (TEQC), benzo(a)pyrene equivalent (BaPeq), contamination factor (CF), pollution load index (PLI), hazard quotient (HQ), hazard index (HI), toxic unit for individual PAHs (TU) and PAHs mixture (TUm) have been evaluated. Besides, the effect of PAHs contamination on soil biological properties has also been investigated and correlated with PAHs concentrations. The TEQc of eight PAHs was recorded in the range of 0.06-5.0 mg kg-1 soil, whereas the BaPeq value was 25.3 mg kg-1 soil which exceed the permissible limit. Similarly, CF (85.5-1668.2), PLI (322.8), HQ (311.7-8340.9), HI (26,443.8), TU (227.9-3821.6) and TUm(7916.2) also exceed the permissible values for non-toxic conditions indicating carcinogenic risk for humans. Besides, activities of soil dehydrogenase, urease, alkaline-phosphatase, catalase, amylase and cellulase were decreased by 1.5-2.3 folds in the contaminated soil than control. The results of Pearson's correlation matrix also established negative impact of PAHs on the soil's biological properties.

Understanding biochemical defense and phytoremediation potential of Leucas aspera in crude oil polluted soil.

The phytoremediation potential and enzymatic defense of a medicinal herb Leucas aspera was studied in the crude oil contaminated soil. The productivity, antioxidants, and phytochemical and functional group profiles of the plant species in stress conditions were investigated. Besides, changes in enzymes, beneficial bacterial population, and physico-chemical and total oil and grease (TOG) profiles in the contaminated soil were also studied. The results showed improvement in physico-chemical conditions, increase in beneficial bacterial population (4.1-5.4 folds), and decrease in TOG (31.3%) level of the contaminated soil by end of the experimental trials. The L. aspera treated contaminated soil showed enhancement in dehydrogenase (32.3%), urease (102.8%), alkaline phosphatase (174.4%), catalase (68.5%), amylase (76.16%), and cellulase (23.6%) activities by end of the experimental trials. Furthermore, there were significant variations in leaf area index, chlorophyll, and biomass contents of the experimental plant as against the initial level and control. Besides, the significant reduction in IC50 values (24-27.4%) of L. aspera samples grown in contaminated soil confirms the strong antioxidant enzymatic defense of the plant species against the crude oil associated abiotic stress. The Fourier-transform infrared (FT-IR) analysis confirmed the uptake and metabolism of aliphatic hydrocarbons, aldehydes, alkyl halides, and nitro compounds by the experimental plant from the contaminated soil.

Eisenia fetida for vermiconversion of waste biomass of medicinal herbs: Status of nutrients and stability parameters.

Vermiconversion possibility of waste biomass of two medicinal herbs Zingiber officinale and Curcuma longa has been investigated. The Eisenia fetida, an epigeic earthworm was used in the vermicomposting process. The vermicomposting caused shifting in pH towards neutral range, reduction in electrical conductivity, total organic carbon, C/N and C/P ratios whereas1.8-2.73 folds enhancement in macronutrients (TKN, AP, T Ca and T Mg) and ash contents in the substrate mixture. The heavy metals and trace elements content in the vermicompost were found within 3.25-1380 mg/kg and are under the permissible limits of compost applications. Besides, high germination index value in the vermicompost extract indicates loss of phytotoxicity and safe agricultural application potential of the end product. Finally, enhanced growth in Eisenia fetida confirms the application potential of harvested waste biomass as the raw materials for vermiconversion process.

Vermicomposting of harvested waste biomass of potato crop employing Eisenia fetida: changes in nutrient profile and assessment of the maturity of the end products.

The vermicomposting potential of waste biomass of potato crops that are generated at the time of harvesting was studied employing Eisenia fetida. The experiment was carried out in pots, and two treatments were applied during the study. In the first treatment, only potato plant biomass (PPB) was taken as the raw materials; whereas in the second treatment, a mixture of PPB with cow dung was engaged in the proportion of 5:1. The vermicomposted materials showed a reduction in C/N ratio, humification index, enhancement in nutrients profiles, ash contents, nitrogen-fixing, phosphate, and potassium solubilizing bacterial population. The macronutrient enhancement in the vermicompost samples was recorded 3.8-4.4-fold for total N, 5-5.6-fold in available P, 1.6-fold in total K, 5.2-6.2-fold in total Ca, and 1.6-fold in total Mg contents. The reduction in C/N was found in the range of 92.5-94.4% in the vermicompost samples. The scanning electron microscope (SEM) images showed higher disintegration in the vermicompost products when compared with initial raw material and compost samples. The addition of cow dung significantly enhanced the quality and quantity of vermicompost final products besides positively affecting the earthworm population and biomass by the end of 60 days of experimental trials.

Enzymatic defense of Cyperus brevifolius in hydrocarbons stress environment and changes in soil properties.

Hydrocarbons or crude oil contamination of soil is still a burning problem around the globe. The herbs competent that are to survive in hydrocarbons contaminated habitats have some adaptive advantages to cope up with the adverse situations prevailing in that environment. In the present study, the adaptive response of Cyperus brevifolius in the heavily polluted soil with crude oil has been investigated in terms of survivability, changes in productivity, antioxidants, phytochemicals and functional group pro files of the plant species. Besides, changes in enzymes, beneficial bacterial population and physico-chemical conditions of contaminated soil were also studied during 60 days of experimental trials. The results showed significant enhancement in activities of soil dehydrogenase, urease, alkaline phosphatase, catalase, and amylase whereas reduction in cellulase, polyphenol oxidase and peroxidase activities. There was a significant increase in nitrogen fixing, phosphate and potassium solubilizing bacterial population, improvement in physico-chemical conditions and a decrease in total oil and grease (TOG) levels. Besides there was significant variations in the productivity parameters and antioxidant profiles of Cyperus brevifolius in hydrocarbons stress condition suggesting enzymatic defense of the herb. The fourier-transform infrared (FT-IR) analysis indicated uptake and metabolism of some hydrocarbon components by the experimental plant from the hydrocarbons polluted soil.

Effects on anatomy of some abundantly growing herbs in the effluents contaminated soil of oil refinery.

The soil contaminations from refinery effluents are still a burning problem in the oil-producing nations of the globe. In the present study, the effect of oil refinery effluents on anatomical characteristics of some selected herbs has been studied. The abundantly growing herb species of the contaminated sites that includes Ageratum conyzoides, Alternanthera paronychioides, and Cyperus brevifolius were selected for the anatomical investigation. The samplings site of these herbs was adjacent to Numaligarh oil refinery, Assam, India, where a huge amount of oil effluents are released every day. For comparison, the same plant species were collected from the control sites where effluent contamination was not evident. The results showed that anatomical sections of both shoots and roots of the studied herbs are adversely affected by oil refinery effluents contamination and showed various structural abnormalities. Dark/blackish depositions were traced in the different tissues that include the epidermis, cortex, vascular bundles and pith region in the plant samples collected from the effluents contaminated areas. The results also revealed widening, thickening, and reduction of different tissues of the studied plants besides affecting overall shoot diameter; cell sizes; and length of epidermis, cortex, vascular bundles, and pith as a defense mechanism against the adverse condition created due to effluent contamination. Such abnormalities were not observed in control plants.

Phytosociology and antioxidant profile study for selecting potent herbs for phytoremediation of crude oil-contaminated soils.

Crude oil exploration activities affect the surrounding vegetation. The present investigation deals with the study of phytosociology and biochemical profiles of the herbaceous community in the active and abandoned oil drilling sites of crude oil-explored area. For comparison, a similar investigation was also carried out in control sites where oil exploration activities were not evident. At first, a phytosociological investigation was carried out and based on the results obtained antioxidant enzyme profiles of dominant herbs were studied to understand their defense mechanism to crude oil-associated stress. A total of 69 plant species belonging to 20 families were recorded in the studied sites and the family Cyperaceae was the most dominant in the crude oil-contaminated sites. The results revealed that the plants growing near the oil-explored-contaminated sites exhibit a higher level of DPPH and H2O2 radical scavenging activities as compared to control plant samples. For DPPH assay, the lowest IC50 value was exhibited by Cyperus rotundus which was recorded to be 31.49 and 55.31 respectively for the samples of contaminated and control sites. Again, in the case of H2O2 scavenging activity assay, Parthenium hysterophorus showed the lowest IC50 values of 27.48 and 63.07 for the samples of contaminated and control sites respectively. As a whole, the findings confirm the superior defense mechanism of some dominant herbs of the contaminated sites that include Torenia flava, Croton bonplandianus, Eclipta alba, Cyperus rotundus, Cyperus brevifolius, and Parthenium hysterophorus and their suitability for use in phytomanagement practices.

Accumulation of heavy metals in selected medicinal plants.

In this review, we evaluate the reports published between 1993 and 2011 that address the heavy metal accumulation in 88 medicinal plant species. We compare the safe limits for heavy metals set by governmental agencies vs. the levels at which such metals actually exist in selected medicinal plants. We also evaluate the uses and effectiveness of medicinal plants in health care, and assess the hazards of medicinal plant uses, in view of the growing worldwide use of medicinal plants. From our extensive review of the literature, we discovered that a maximum permissible level (MPL) of Pb is exceeded in 21 plant medicine species, Cd in 44 species, and Hg in 10 species. Vetiveria zizanioides a potential candidate species for the treatment of cardiovascular diseases absorb a wide range of heavy metals from metal-contaminated soils. We believe that this species is the single most impressive example of a potentially hazardous medicinal plant. Based on our review, we endorse the hypothesis that heavy metal accumulation by medicinal plants is mainly caused by extraction of soluble metals from contaminated soil, sediments and air. One continuing problem in protecting consumers of plant-based medicines is that permissible levels of all heavy metals in herbal medicine have not yet been standardized by regulating governmental entities. Moreover, there are few limit tests that exist for heavy metal content of medicinal plants, or permissible limits for essential dietary minerals, in most medicinal plants. The dearth of such limits hamstrings development of medicinal plant research and delays the release of either new or improved versions of medicinal plants or their components. In the present review, we emphasize that medicinal plants are often subjected to heavy metal contamination and that the levels at which these heavy metals sometimes occur exceeds permissible levels for some species. Therefore, collecting medicinal plants from areas that are, or may be, contaminated should be discouraged and banned if possible.