Biostimulation Processes Research Articles

Inclusion of Pseudomonas fluorescens into soil-like fraction from municipal solid waste management park to enhance plastic biodegradation.

Single-use facial masks which are predominantly made out of polypropylene is being used and littered in large quantities during post COVID-19 situation. Extensive researches on bioremediation of plastic pollution on soil led to the identification of numerous plastic degrading microorganisms. These organisms assimilate plastic polymers as their carbon source for synthesizing energy. Pseudomonas fluorescens (PF) is one among such microorganism which is being identified to biodegrade plastic polymers in controlled environment. The natural biodegradation of facial mask in soil-like fraction collected from municipal waste management site, bioaugmentation of the degradation process with Pseudomonas fluorescens, biostimulation of the soil with carbonless nutritional supplements and combined bioaugmentation with biostimulation process were studied in the present work. The study has been conducted both in controlled and in natural condition for a period of 12months. The efficiency of the degradation was verified through FTIR analyses using carbonyl index, bond energy change, Loss in ignition (LOI) measurement along with CHNS analyses of residual substances. The analysis of results reported that carbonyl index (in terms of transmittance) was reduced to 46% of the control batch through the inclusion of PF in natural condition. The bioaugmented batch maintained in natural condition showed 33% reduction of LOI with respect to the control batch. The unburnt carbon content of the residual matter obtained from the furnace were analysed using CHNS analyser and indicated the lowest carbon content in the same bioaugmented batch. In this study, an attempt is made to verify the feasibility of enhancing biodegradation of single-use facial mask by bioaugmentation of soil-like fraction available in solid waste management park with Pseudomonas fluorescens under natural condition. CHNS and FTIR analysis assures the biodegradation of plastic waste in the soil-like fraction using Pseudomonas fluorescens under both controlled and natural environmental condition.

Removal of residual organic pollutants from pulp paper industry wastewater using bacterial strains Acinetobacter baumannii (OK582199) PC4 and Bacillus cereus (OK582201) PC10 via biostimulation and bioaugmentation process

This study examines how native bacteria, combined with two specific aerobic strains (Acinetobacter baumannii PC4 and Bacillus cereus PC10), contribute to the detoxification of pulp and paper industrial wastewater (PPIW) through biostimulation and bioaugmentation processes. The growth of two native bacteria were stimulated in pulp paper industry wastewater by the addition of carbon (1% glucose) and nitrogen (0.5% peptone w/v). After the growth of these native bacteria in biostimulation process showed significant reduction in various physico-chemical parameters i.e. lignin (53%), color (46%), COD (76%), and BOD (86%). Similarly, reductions in various heavy metals were also observed, such as Fe (73%), Zn (36%), Cr (41%), Cu (22%), and Ni (65%). The growing native bacterial co-culture were identified as Enterobacter cloacae strain PC7 (OQ672613) and Bacillus sp. strain PCB (OK614116). However, the addition of Acinetobacter baumannii (OK582199) PC4 and Bacillus cereus (OK582201) PC10 enhanced the reduction of various physico-chemical parameters in range of 10–––28%. Consequently, the UV–Vis absorption peak showed reduction due to the decolorization of wastewater and degradation of various pollutants. Moreover, GC–MS analysis indicated that most of the compounds detected in the control were diminished after bacterial treatment. However, compounds such as Pentadecane, 2-Methyl, Silane (dodecylosy) trimethyl, Octadecanoic acid, trimethylsilyl ester, and Docasane were noted as recalcitrant. Additionally, new metabolic products such as 1-ethyl-5,6-dimethoxy-2,3-dihydroindole, Trimethylsily ether of glycerol, and 1-(Trimethylsilylmethyl1) dimethylsilyloxy tetradecane were detected. Due to degradation of various pollutants toxicity reductions were found up to 76% during a comparative evaluation between control and bacterial treated wastewater using the Phaseolus mungo L. seed germination test. Hence, it was concluded that the biostimulation and bioaugmentation process would be an effective technique for degrading residual organic pollutants from pulp and paper industrial wastewater (PPIW) for safe disposal.

Removal of polycyclic aromatic hydrocarbons (PAHs) from produced water using the microalgae Chlorella vulgaris cultivated in mixotrophic and heterotrophic conditions

Chlorella vulgaris was cultivated for 15 days in 10 different treatments under mixotrophic and heterotrophic conditions, using wastewater from oil and poultry industries as the culture medium. The blends were made with produced water (PW), sterilized produced water (PWs), sterilized poultry wastewater (PoWs), sterilized seawater (SWs), and the addition of sodium nitrate to evaluate cell growth in treatments and the removal of PAHs. The heterotrophic condition showed more effective removal, having an initial concentration of 3.93 μg L−1 and a final concentration of 0.57 μg L−1 of total PAHs reporting 83%, during phycoremediation of (PW) than the mixotrophic condition, with an initial concentration of 3.93 μg L−1 and a final concentration of 1.96 and 43% removal for the PAHs. In the heterotrophic condition, the blend with (PWs + SWs) with an initial concentration of 0.90 μg L−1 and a final concentration of 0.32 μg L−1 had 64% removal of total PAHs compared to the mixotrophic condition with 37% removal having an initial concentration of 0.90 μg L−1 and a final concentration of 0.56 μg L−1. However, the best result in the mixotrophic condition was obtained using a blend of (PWs + PoWs) that had an initial cell concentration of 1.18 × 105 cells mL−1 and reached a final cell concentration of 4.39 × 105 cells mL−1, an initial concentration of 4.76 μg L−1 and a final concentration of 0.37 μg L−1 having a 92% total removal of PAHs. The biostimulation process increased the percentage of PAHs removal by 45% (PW) in the mixotrophic condition. This study showed that it is possible to allow an environmental remediation strategy that significantly reduces effluent toxicity and generates high value-added biomass in contaminated effluents rich in nutrients and carbon, based on a circular bioeconomy model.

Bioremediation of an industrial soil contaminated by hydrocarbons in microcosm system, involving bioprocesses utilizing co-products and agro-industrial wastes.

The present study describes practical implication of bioaugmentation and biostimulation processes for bioremediation of an industrial soil chronically contaminated by hydrocarbons. For this purpose, biomass production of six autochthonous hydrocarbon-degrading bacteria were evaluated as inoculum of bioaugmentation strategy, by testing carbon and nitrogen sources included co-products and agro-industrial waste as sustainable and low-cost components of the growth medium. Otherwise, biostimulation was approached by the addition of optimized concentration of nitrogen and phosphorus. Microcosm assays showed that total hydrocarbons (TH) were significantly removed from chronically contaminated soil undergoing bioremediation treatment. Systems Mix (bioaugmentation); N,P (biostimulation) and Mix + N,P (bioaugmentation and biostimulation) reached higher TH removal, being 89.85%, 91.00%, 93.04%, respectively, comparing to 77.83% of system C (natural attenuation) at 90days. The increased heterotrophic aerobic bacteria and hydrocarbon degrading bacteria counts were according to TH biodegrading process during the experiments. Our results showed that biostimulation with nutrients represent a valuable alternative tool to treat a chronically hydrocarbon-contaminated industrial soil, while bioaugmentation with a consortium of hydrocarbon degrading bacteria would be justified when the soil has a low amount of endogenous degrading microorganisms. Furthermore, the production of inoculum for application in bioaugmentation using low-cost substrates, such as industrial waste, would lead to the development of an environmentally friendly and attractive process in terms of cost-benefit.

Biogeochemical modelling to assess benzene removal by biostimulation in aquifers containing natural reductants.

Biostimulation of aquifers contaminated with gasoline spills is vigorously affected by the biogeochemical environment existing there. In this study, biostimulation of benzene is simulated using a 2D coupled multispecies biogeochemical reactive transport (MBRT) model. The model is implemented at an oil spill site near a hypothetical aquifer containing natural reductants. Multiple electron acceptors are introduced to promote faster biodegradation rate. However, after reaction with natural reductants, it reduces the number of available electron acceptors, acidifies the subsurface environment, and inhibits bacterial growth. These mechanisms are assessed using seven coupled MBRT models sequentially. The finding of the present analysis reveals that biostimulation has caused a substantial drop in concentration of benzene and is efficient in reducing its penetration depth. The results also shows that the intervention of natural reductants in the biostimulation process is slightly diminished by pH adjustment of aquifers. When the pH level in aquifer changes from acidic pH 4 to neutral pH 7, it is observed that the biostimulation rate of benzene as wellas microbial activity increases. Electron acceptors consumption is more at neutral pH. Overall, it can be inferred from zeroth-order spatial moment and sensitivity analyses that retardation factor, inhibition constant, pH, and dispersivity in vertical direction significantly affect benzene biostimulation in aquifers.

Microbial community profiling in bio-stimulated municipal solid waste for effective removal of organic pollutants containing endocrine disrupting chemicals

The study was aimed to improve the degradation of organic pollutants in municipal solid waste (MSW) through the bio-stimulation process. The results showed that the physico-chemical properties of MSW (control) had a high value of pH (9.2 ± 0.02); total suspended solids (TSS: 1547 ± 23 mg/kg−1), and total dissolved solids (TDS:76 ± 0.67 mg/kg−1). After the biostimulation process (biostimulated MSW), the physico-chemical parameters of MSW were reduced as pH (7.1 ± 0.01); TSS (41 ± 0.01 mg/kg−1), and TDS (789 ± 03 mg/kg−1). Furthermore, the major organic pollutants detected from MSW by gas chromatography-mass spectroscopy (GC-MS) analysis at different retention time (RT) were hexadecane (RT-8.79); pentadecane (RT-9.36); and hexasiloxane (RT-9.43) while these organic pollutants were degraded after the biostimulation process. The whole-genome metagenome sequencing size (%) analyses showed major groups of bacteria (40.82%) followed by fungi (0.05%), virus (0.0032%), and archaea (0.0442%) in MSW. The species richness and evenness of the microbial community were decreased substantially due to the biostimulation treatment. The total number of genes in the biostimulated MSW (PS-3_11267) sample were 465302 whereas the number of genes in the control MSW (PS-4_11268) sample were 256807. Furthermore, the biostimulated MSW (PS-3_11267) aligned the reads to bacteria (19502525), fungi (40030), virus (3339), and archaea (12759) genomes whereas the control sample (PS-4_11268) aligned the reads to bacteria (17057259), fungi (19148), virus (1335), and archaea (18447) genomes. Moreover, the relative abundance at genus level in biostimulated MSW (PS-3_11267) (Ochrobactrum and Phenylobacterium), phylum; (Proteobacteria and Actinobacteria), and species (Chthoniobacter flavus and Vulgatibacter incomptus) level was the most abundant. The results provided valuable information regarding the degradation of organic pollutants in MSW by microbial communities through biostimulation for the prevention of soil pollution and health protection.

Remediation of high-concentration Cr(VI)-contaminated soils with FeSO4 combined with biostimulation: Cr(VI) transformation and stabilization

Efficient and sustainable technologies for cleaning up of hexavalent chromium (Cr(VI)) contaminated soil are under urgent demand. In this study, chemical reduction and biostimulation were combined to remediate contaminated soil with a high concentration of hexavalent Cr(VI) to compensate for the shortcomings of single-treatment technology. The Cr(VI) concentration, Cr speciation, and bacterial diversity of the contaminated soil were measured after combined remediation with ferrous sulfate (FeSO4) and different electron donors. The changes in various indexes in the soil after microbial death were also studied. The results indicated that the optimal reduction rate of Cr(VI) was as high as 95.20% when 10% FeSO4 was combined with lactic acid. The water-soluble fraction of Cr with the highest toxicity in the soil was almost completely converted into other stable fractions. Stabilization experiments proved that Cr(III) in the remediated soil did not revert to Cr(VI) after microorganism death, and had a good stabilization effect. The bacterial diversity results indicated that Acinetobacter spp. and Pseudomonas spp. were the dominant species during the biostimulation process and might be involved in the reduction of Cr(VI).

Bioaugmentation and biostimulation of crude oil contaminated soil: Process parameters influence

In this study, investigation of bioaugmentation and biostimulation process parameters’ influence on biodegradation effectiveness of bacteria isolates in a crude oil polluted soil for 60 days was conducted. A native environment of crude oil polluted site was considered for bacteria isolation. Dilution plate technique was used for bacteria culturing under laboratory conditions. Central composite design embedded in design expert software was used for the design of experiment and optimum point prediction. The influence of nitrogen:phosphorus nutrient ratio and bacteria concentration at varying crude oil concentration and soil pH on percentage of total petroleum hydrocarbons (TPH) biodegraded was investigated. Biostimulation was highly significant on the percentage of TPH biodegraded as revealed by experimental results. Degradation efficiency of 93.75% was obtained for a soil pH of 10 contaminated with 100 g/Kg of crude oil using 600 cell/g of bacteria supplemented with 8 g/g of nitrogen-phosphorus ratio. The model developed was effective for future prediction with better correlation between experimental and predicted values. A biodegradation efficiency of 77.42% was achievable at the optimum predicted point by central composite design. Hydrocarbons biodegradation in the crude oil contaminated soil via the action of supplemented bacteria isolates was revealed. Conclusively, bacteria isolates from native polluted site could be applied as effective scavenger for hydrocarbons in crude oil contaminated soil.

Pollution Reduction Potential of Bacteria Isolated from Eutrophicated Lake

Introduction: Eutrophication is one of the most widespread environmental problems of inland waters due to the increased growth of microscopic floating plants, algae, and the formation of dense mats of larger floating plants such as water hyacinth. Water hyacinth grow only in water contaminated with point and non-point sources of pollutants. Hence, the resources get eutrophicated supporting the growth of greens. The water quality of eutrophicated lake is adversely affected and that water acts as contaminant containment. Methods: Therefore, with the background thought that microbes degrade the pollutants, the native microorganisms isolated from the water samples of the eutrophicated lake in Lakshmipuram Lake of Theni district was mass multiplied and used for pollution degradation (1). Results & Discussions: A total of 10 bacterial cultures were obtained. The organisms that were isolated from the eutrophicated lake was identified as Xanthomonas, Pseudomonas fluorescens, Enterobacter, Pseudomonas sp, Bacillus by comparing the morphological and bio-chemical characters with the Bergey’s manual. All the cultures tend to reduce the pollution load of the eutrophicated lake. However, the best-known culture for pollution reduction was observed to be EL3 (P. fluorescence). EL3 recorded 75.19% reduction of total nitrogen, 88.05 % reduction of total phosphorous, and 100% reduction in heavy metals. Conclusions: Hence, the potential of this organism may be utilized through biostimulation process to restore the eutrophicated lakes (2). Keywords: Water hyacinth, Bacteria, Pollution and Reduction References Higa,T. 1991. Effective microorganisms: A biotechnology for mankind. In J.F. Parr, S.B. Hornick, and C.E. Whitman (ed.) Proceedings of the First International Conference on Kyusei Nature Farming. U.S. Department of Agriculture, Washington, D.C. USA, 8-14. Prithiv Raj. V, T. Ilakiya, E. Parameswari and Davamani. V. 2020. Assessment of New Ecotechnological Measures to Restore the Eutrophicated Lake. Int.J.Curr.Microbiol.App.Sci. 9(03): 1457-1466.

Increase in Total Petroleum Hydrocarbons Removal Rate in Contaminated Mining Soil Through Bioaugmentation with Autochthonous Fungi During the Slow Bioremediation Stage

The removal of total petroleum hydrocarbons (TPHs) from contaminated mining soil was carried out under in vitro conditions. The aerobic consumption of TPH in the slow bioremediation stage via biostimulation with native microorganisms and biostimulation-bioaugmentation with autochthonous fungal isolates was evaluated. The initial TPH concentration was 70,880 ± 975 mg TPH/kg soil, soil was amended with nutrients at a C:N:P ratio of 100:15:1, the water content was adjusted to the soil field capacity, and batch microcosm reactors were incubated at room temperature (20.5 ± 3.1°C) for 90 days. The bioaugmentation process was tested using four hydrocarbonoclastic fungal strains isolated from the same contaminated mining soil individually and a mixed culture of the four isolates. The molecular characterization of the isolated fungi was based on sequence analysis of 18S rRNA, and the fungi were identified as Aspergillus niger MT786339.1, Aspergillus fumigatus MT786338.1, Aspergillus terreus MT786341.1, and Aspergillus flavus MT786340.1. The best TPH removal was achieved by inoculation with the fungal consortium (57 ± 1.97%) at 45 days (slow stage) after initiating the biostimulation process, followed by inoculation with Aspergillus niger (49 ± 1.2%), Aspergillus terreus (44 ± 0.67%), Aspergillus fumigatus (35 ± 0.98%), and Aspergillus flavus (32 ± 0.38%), while the degradation rate achieved with native microorganisms was only 21.6 ± 1.5%; statistical analysis of the results showed significant differences.

Characterization of Autochthonous Bacteria Capable for Degradation of Residual Organic Pollutants of Pulp Paper Mill Effluent by Biostimulation Process

Characterization of Autochthonous Bacteria Capable for Degradation of Residual Organic Pollutants of Pulp Paper Mill Effluent by Biostimulation Process

Highlighting the Crude Oil Bioremediation Potential of Marine Fungi Isolated from the Port of Oran (Algeria)

While over hundreds of terrestrial fungal genera have been shown to play important roles in the biodegradation of hydrocarbons, few studies have so far focused on the fungal bioremediation potential of petroleum in the marine environment. In this study, the culturable fungal communities occurring in the port of Oran in Algeria, considered here as a chronically-contaminated site, have been mainly analyzed in terms of species richness. A collection of 84 filamentous fungi has been established from seawater samples and then the fungi were screened for their ability to utilize and degrade crude oil. A total of 12 isolates were able to utilize crude oil as a unique carbon source, from which 4 were defined as the most promising biodegrading isolates based on a screening test using 2,6-dichlorophenol indophenol as a proxy to highlight their ability to metabolize crude oil. The biosurfactant production capability was also tested and, interestingly, the oil spreading and drop-collapse tests highlighted that the 4 most promising isolates were also those able to produce the highest quantity of biosurfactants. The results generated in this study demonstrate that the most promising fungal isolates, namely Penicillium polonicum AMF16, P. chrysogenum AMF47 and 2 isolates (AMF40 and AMF74) affiliated to P. cyclopium, appear to be interesting candidates for bioremediation of crude oil pollution in the marine environment within the frame of bioaugmentation or biostimulation processes.

Enhanced bioremediation of lindane-contaminated soils through microbial bioaugmentation assisted by biostimulation with sugarcane filter cake

Lindane is a toxic and persistent organochlorine pesticide, whose extensive use generated its accumulation in different environmental matrices. Bioremediation is a promising technology that can be used combining bioaugmentation and biostimulation processes to soil restoration. The aim of the present work was to determine the conditions of maximum lindane removal by bioaugmentation with an actinobacteria consortium and biostimulation with sugarcane filter cake (SCFC). The assays were carried out on lindane-contaminated silty loam (SLS), clayey (CS), and sandy (SS) soils. Through complete factorial designs, the effects of three abiotic factors (moisture content, proportion and size of SCFC particles) were evaluated on lindane removal. In addition, a response optimizer determined the optimal conditions for pesticide removal in bioaugmented and biostimulated soils, in the range of levels studied for each factor. In these conditions, bioaugmentation of biostimulated soils increased the pesticide removal (SLS: 61.4%, CS: 70.8%, SS: 86.3%), heterotrophic microbial counts, and soil enzymatic activities, and decreased lindane T1/2, regarding the non-bioaugmented biostimulated controls, after 14 days of assay. The values of these parameters confirmed the efficiency of the bioremediation process. Finally, the viability of the four strains was demonstrated at the end of the assay. The results indicate that the simultaneous application of bioaugmentation with the actinobacteria consortium and biostimulation with SCFC constitutes a promising tool for restoring soils contaminated with lindane, by using the optimal conditions obtained through the factorial designs.

D-optimal Design Application to Study Enhanced Biostimulation of Used Motor Oil Contaminated Soil

The indiscriminate disposal of fresh and used motor oil into the environment (land and water) is a common practice in Nigeria and this practice has contributed to its soil contamination and makes up a greater percentage of polluted ground in the world. Over the years, the contamination of auto-mechanic workshops by used oil and fresh oil has been left uncared for, Soil contaminated with fresh and used motor oil creates a serious effect on plant tissues, soil components, and its microorganisms, human and other animal health. Optimization of a biostimulation process used in the treatment of used motor oil contaminated soil has been carried out. D-optimal design of response surface methodology with one numerical factor and a categorical factor at two levels was employed to generate 10 experimental runs for the biostimulation system. The input variables of the system were palm bunch ash (a stimulant) and pollution level. The two levels of the latter factor considered were 5% and 10 % (w/w) pollution level, while the response of the system was oil and grease (O&G) removal. The biostimulation experiments were carried out according to the RSM design, and the experimental data obtained were analyzed using the quadratic model. The results of the analyses showed that the developed quadratic model was able to represent the system with both input factors affecting the system significantly since p-values for the model was found to be less than 0.05. The results also showed that O&G removal was affected by both the PBA and the pollution level. It was also observed from the numerical optimisation carried out that 100 % and 83.36 % O&G removal was attained at 5 % and 10 % pollution level respectively after ten weeks of the study. The findings of this work revealed that palm bunch ash (PBA) can be used as a stimulant for the bioremediation of used motor oil contaminated soil. Thus, its application in the treatment of oil-contaminated soil is highly recommended.

Hydrocarbon-contaminated Antarctic soil: changes in bacterial community structure during the progress of enrichment cultures with different n-alkanes as substrate

Hydrocarbon contamination in soils from extremely cold areas, such as those from Antarctica, requires the development of specific remediation strategies for cleaning up anthropogenic pollution. Previous reports evidenced that after on-site biostimulation process of gasoil-contaminated Antarctic soils, 20% of the initial hydrocarbons remained undegraded (mainly C11–C14 n-alkanes). In the present work, these n-alkanes were added as sole carbon and energy source to enrichment cultures inoculated with the previously treated soil (biostimulation) as microorganism’s source to investigate changes occurring in the bacterial community structure. Three subcultures (8, 16, and 24 days) were performed from each enrichment culture. Changes in bacterial communities among different cultures and its subcultures were evidenced by Denaturing Gradient Gel Electrophoresis (DGGE). Results showed that even differences of one C in the alkane chain-length led to different community structures that evolved divergently from the original one. Clusters analysis showed that while samples grouped mainly by culture time, substrate-dependent differences were also evident. Isolation of biological tools for bioremediation from the cultures showed that Pseudomonadaceae members were omnipresent, whereas Rhodococcus spp. were obtained in cultures with the longest chain-length substrates. Results provided evidence about the presence of certain substrate preference of soil bacteria (even when substrates differed only in one C-atom of their chain-length), leading to different community structures. A collection of psychrotolerant hydrocarbon degrading/tolerant strains was obtained, representing a valuable tool for the design of a bioaugmentation strategy as a second, more specific stage, targeting the remnant hydrocarbons after a first bioremediation process involving biostimulation.

Biochar Influenced Microbial Community Succession and Metabolic Characteristic During the Dropping Crude Remediation

This study determined the fluctuations of bacterial community structures in biochar biostimulation process with different types of nutrient amendments. Results showed that suitable amendment ratio of biochar and nutrients can greatly increase the remediation efficiency, biocharaddition influenced microbial community structure and metabolic characteristics of the remediation. Proteobacteria, Actinobacteria, and Fimicutes were the dominant phyla throughout the process, and biochar addition significantly increased the relative abundance of Firmicutes phylum. The detected abundance of bacterial genes related were also different, Amino acid transport and metabolism, Carbohydrate transport and metabolism were increased with biochar addition and had great influence on the bacterial community structure. These results indicated that biochar addition improved the degradation process meanwhile significantly regulated the microbial community and function.

Biostimulation of carbonate precipitation process in soil for copper immobilization.

The urease-based microbially induced carbonate precipitation (MICP) is known as effective remediation strategy in soil metals remediation; however, all related studies confined to bioaugmentation. In the present study, biostimulation process was adopted for the first time in accelerating MICP in copper (Cu) immobilization in soil. The abundance, composition, and diversity of the bacterial community after biostimulation were assessed with MiSeq Illumina sequencing analysis that confirmed number and types of ureolytic and calcifying bacteria grown significantly leading to MICP process, compared to untreated soil. The results demonstrated that biostimulation induced calcite precipitation in soil that immobilized Cu mainly in carbonated fraction of soil, while soluble-exchangeable fraction decreased from 45.54 mg kg-1 to 1.55 mg kg-1 Cu in soil. Scanning electron microscopy (SEM) cum energy-dispersive X-ray spectroscopy (EDX) evaluated structure and elemental composition in Cu immobilization after biostimulation. Fourier Transform-Infra Red (FTIR) spectroscopy depicted functional chemical groups involved in copper immobilization, while X-Ray Diffraction (XRD) identified main crystalline phases or biominerals formed during biostimulation in order to carryout Cu remediation from soil.

Biological indicators for evaluating soil quality improvement in a soil degraded by erosion processes

Erosion is one of the main soil degradation problems. It diminishes soil biological activity and therefore its quality. The aim of the study was to evaluate if the application of two biostimulation processes could significantly increase biological activity, and therefore productivity, in soils deteriorated by erosion. This was done without synthetic fertilizers but with treatments accessible for farmers, in line with the 2030 Agenda for Sustainable Development. In particular, the addition of a soil microorganism suspension or Macrocystis pyrifera algae concentrate was evaluated. Soil samples were taken from a field area (Bihor County, Romania) affected by surface erosion processes. In particular, microbial mass, dehydrogenase activity (DHA), and the bacteria and fungi presence were analyzed for three soil uses (corn, black locust and uncultivated field with terracing) and in different locations (above a slope, at the midpoint and below it). A bio-stimulation process (addition of a microbial suspension or seaweed concentrate based on the Macrocystis pyrifera algae; incubation for 24 h) was used in order to improve the activity of the soil with the lowest values of activity. Statistical differences in DHA, bacterial numbers, and microbial biomass were found depending on field use and the areas from which the soil samples were gathered. Higher values of the biological parameters were in general recorded in the middle part of the slope, because they favor bioaccumulation processes (e.g., actual and potential dehydrogenase activity values of about 3 mg TPF/10 g dry soil). The use of microbial suspensions did not significantly stimulate DHA for the soils with a low biological potential. This activity was stimulated by adding the seaweed concentrate to the soil. The use of the seaweed concentrate can be a good practice for improving activity in eroded soil. The study provides useful indications for better soil fertility management, in line with many of the goals of the 2030 Agenda For Sustainable Development.

Near infrared low-level laser therapy and cell proliferation: The emerging role of redox sensitive signal transduction pathways.

Lasers devices are widely used in various medical fields (eg, surgery, dermatology, dentistry, rehabilitative medicine, etc.) for different applications, ranging from surgical ablation of tissues to biostimulation and pain relief. Laser is an electromagnetic radiation, which effects on biological tissues strongly depends on a number of physical parameters. Laser wavelength, energy output, irradiation time and modality, temperature and tissue penetration properties have to be set up according to the clinical target tissue and the desired effect. A less than optimal operational settings, in fact, could result in a null or even lethal effect. According to the first law of photobiology, light absorption requires the presence of a specific photoacceptor that after excitation could induce the activation of downstream signaling pathways. Low-level lasers operating in the red/near infrared portion of the light spectra are generally used for biostimulation purposes, a particular therapeutic application based on the radiant energy ability to induce nonthermal responses in living cells. Biostimulation process generally promotes cell survival and proliferation. Emerging evidences support a low-level laser stimulation mediated increase in "good" reactive oxygen species, able to activate redox sensitive signal transduction pathways such as Nrf-2, NF-kB, ERK which act as key redox checkpoints.

RETRACTED: Biodegradation of Endocrine-Disrupting Chemicals and Residual Organic Pollutants of Pulp and Paper Mill Effluent by Biostimulation

Effluent discharged from the pulp and paper industry contains various refractory and androgenic compounds, even after secondary treatment by activated processes. Detailed knowledge is not yet available regarding the properties of organic pollutants and methods for their bioremediation. This study focused on detecting residual organic pollutants of pulp and paper mill effluent after biological treatment and assessing their degradability by biostimulation. The major compounds identified in the effluent were 2,3,6-trimethylphenol, 2-methoxyphenol (guaiacol), 2,6-dimethoxyphenol (syringol), methoxycinnamic acid, pentadecane, octadecanoic acid, trimethylsilyl ester, cyclotetracosane, 5,8-dimethoxy-6-methyl-2,4-bis(phenylmethyl)napthalen-1-ol, and 1,2-benzendicarboxylic acid diisononyl ester. Most of these compounds are classified as endocrine-disrupting chemicals and environmental toxicants. Some compounds are lignin monomers that are metabolic products from secondary treatment of the discharged effluent. This indicated that the existing industrial process could not further degrade the effluent. Supplementation by carbon (glucose 1.0%) and nitrogen (peptone 0.5%) bio-stimulated the degradation process. The degraded sample after biostimulation showed either disappearance or generation of metabolic products under optimized conditions, i.e., a stirring rate of 150 rpm and temperature of 37 ± 1°C after 3 and 6 days of bacterial incubation. Isolated potential autochthonous bacteria were identified as Klebsiella pneumoniae IITRCP04 (KU715839), Enterobacter cloacae strain IITRCP11 (KU715840), Enterobacter cloacae IITRCP14 (KU715841), and Acinetobacter pittii strain IITRCP19 (KU715842). Lactic acid, benzoic acid, and vanillin, resulting from residual chlorolignin compounds, were generated as potential value-added products during the detoxification of effluent in the biostimulation process, supporting the commercial importance of this process.