Indigenous Microbes Research Articles

Elicitation of E-waste (acrylonitrile-butadiene styrene) enriched soil bioremediation and detoxification using Priestia aryabhattai MGP1

Given the rise in both usage and disposal of dangerous electronics, there is a catastrophic rise in assemblage of electronic waste (e-waste). E-waste including various plastic resins are among the most frequently discarded materials in electronic gadgets. In current digital era, managing e-waste has become universal concern. From the viewpoint of persisting lacuna of e-waste managing methods, the current study is designed to fabricate an eco-friendly e-waste treatment with native soil bacteria employing an enrichment culture method. In the presence of e-waste, indigenous soil microbes were stimulated to degrade e-waste. Microbial cultures were isolated using enrichment medium containing acrylonitrile-butadiene styrene (ABS) as the primary carbon source. Priestia aryabhattai MGP1 was found to be the most dominant e-polymer degrading bacterial isolate, as it was reported to degrade ABS plastic in disposed-off television casings. Furthermore, to increase degradation potential of MGP1, Response Surface Methodology (RSM) was adopted which resulted in optimized conditions (pH 7, shaking-speed 120 rpm, and temperature 30 °C), for maximum degradation (18.88%) after 2 months. The structural changes induced by microbial treatment were demonstrated by comparing the findings of Field emission scanning electron microscopy (FESEM) images and Fourier Transform Infrared (FTIR) spectra confirming the disappearance of ≡ C─H peaks along with C–H, C=C and C ≡N bond destabilization following degradation. Energy-dispersive X-ray (EDX) analyzers of the native and decomposed e-polymer samples revealed a considerable loss in elemental weight % of oxygen by 8.4% and silica by 0.5%. Magnesium, aluminium and chlorine which were previously present in the untreated sample, were also removed after treatment by the bacterial action. When seeds of Vigna radiata were screened using treated soil in the presence of both e-waste and the chosen potent bacterial strain, it was also discovered that there was reduced toxicity in terms of improved germination and growth metrics as a phytotoxicity criterion.

The Effects of Soil Microbial Disturbance and Plants on Arsenic Concentrations and Speciation in Soil Water and Soils

Arsenic (As) in soils harms soil organisms and plants, and it can enter the human food chain via the dietary consumption of crops. The mobility, bioavailability and toxicity of As are determined by its concentration and speciation. A greenhouse pot experiment was conducted to study the effects of soil microbial disturbance and maize plants on arsenic concentration and speciation in soil (pore) water and soils. Three soil treatments with varying microbial disturbance were designed for this experiment: native soil, sterilized soil and sterilized soil reconditioned with soil indigenous microbes. The three soil treatments were intersected with three levels of As in soils (0, 100 and 200 mg kg−1 spiked As). Ten pots of each treatment were planted with maize, while three pots were filled with soil without maize. The difference between native and reconditioned soil indicated the abiotic sterilization effect (artifact of the sterilization process), while the difference between sterilized and reconditioned soil showed the microbial disturbance effect. Both effects increased As release into soil water. The microbial disturbance effect was more pronounced for organic As species, showing the influence of soil microbes involved in As methylation. The abiotic sterilization effect was more evident in unplanted pots than planted pots and the microbial disturbance effect was observed only in unplanted pots, suggesting that both effects were mitigated by the presence of maize.

The isolation and characterization of indigenous microbes with probiotic potential from gatotan

Indigenous probiotics, which are more adaptive to ethnoecology such as human gut health are found in local food. Therefore, this study aimed to isolate, select, and characterize indigenous microbes as probiotic candidates namely gatotan, which is an Indonesian fermented food from cassava. The potential probiotic was dissolved in artificial gastric acid at pH 2.0 and incubated for 2 hrs, then the De Man Rogosa Sharpe and yeast in Malt Extract medium were used for selective isolation of lactic acid bacteria (LAB). The phenotype including morphological and physiological characteristics as well as the genotype such as PCR-fingerprinting was identified. The results showed that two of the three isolates have the potential to be developed as probiotics possibly growing in an acidic environment. The BGP (LAB) and YGK (yeast) isolates have the highest survival artificial gastric acid of pH 2.0. Furthermore, the BGP from cassava var. white (Malang 2) had a milk-white colony, rod-shaped, undulate colony edges, gram-positive bacteria, nonmotile, negative catalase, and heterofermentative. The YGK from cassava var. yellow (Malang 4) also had white-colony characteristics, irregular shape, rough surface, opaque transparency, spheroidal cell morphology, and amylolytic index of 1.06±0.12 mm. Conclusively, the genotype characterization identified both isolates as Lactobacillus brevis and Pichia kudriavzevii, respectively

Bioaugmentation: an approach to biological treatment of pollutants.

Industrial development and the associated generation of waste requires attention for their management, treatment, and reduction without further degrading the quality of life. Microbes and plant-based bioremediation approaches are some of the sustainable strategies for the biodegradation of harmful pollutants instead of chemical-based treatment. Bioaugmentation is one such approach where microbial strains with the ability to degrade the targeted pollutant are introduced in a polluted environment. Harnessing of microbes from various locations, especially from the site of contamination (indigenous microbes), followed by optimization of the strains, inoculum size, media, and genetic engineering of the microbes along with a combination of strategies such as bio stimulation, phytoremediation is being applied to increase the efficiency of bioaugmentation. Further, bioaugmentation is influenced by various factors such as temperature, the composition of the pollutant, and microbial inoculum which needs to be considered for maximum efficiency of the treatment process. It has numerous advantages such as low cost, sustainability, and easy handling of the contaminants however, the major limitation of bioaugmentation is to increase the survival rate of the microbes involved in remediation for a longer duration in such a highly toxic environment. The review discusses these various aspects of bioaugmentation in brief for its large-scale implementation to address the global issue of pollution and environment management.

Synergistic passivation performance of cadmium pollution by biochar combined with sulfate reducing bacteria

The use of sulfate-reducing bacteria (SRB) for the remediation of Cd-contaminated soil is an attractive option. However, there are various factors that limit the activity of free SRB in soil, which hinders the rapid reduction of sulfate. The immobilized SRB technology has been proposed as a possible solution to overcome this barrier. This study aimed to isolate an Enterobacter sp. strain (SRB15-3-2) with high resistance to Cd2+ from a tailing. Wheat, maize, and rice straws were selected to prepare biochar for inoculating the screened bacteria. The results showed that wheat straw biochar pyrolyzed at 700 °C (WS700) had the highest performance in carrying SRB for Cd2+ immobilization. Furthermore, the WS700 was found to promote SRB15-3-2 for offering S2− and functional groups (C-S, C=O, C=C, C-C=O, and C-O-C, etc.) during the immobilization process. The immobilized SRB with WS700 (ISRBWS700) agglomerated and reacted with Cd2+ to form metal precipitations, predominantly CdS and CdCO3. Which lead to a significant decrease of exchangeable-Cd in contaminated soil (with initial Cd concentrations of 1, 5, and 20 mg/kg) by 18.5%–31.6% after applying the ISRBWS700, indicating that the indigenous soil microbes were been protected from Cd toxicity. Additionally, ISRBWS700 exhibited a synergistic effect in enhancing SRB15-3-2 propagation and the activities of saccharase, urease, and acid phosphatase, compared to the separate treatment of SRB15-3-2 and WS700. Overall, ISRBWS700 prepared in this study represented an accessible way to resolve Cd-contaminated soil, which provided new theoretical insights into eco-friendly technologies for Cd-polluted soil remediation both in development and sustainable aspects.

Isolation and antagonistic test of fungi associated with pummelo citrus against Botryodiplodia theobromae in vitro

Botryodiplodia theobromae is one of the causal agents of diplodia stem-end rot in pummelo citrus. Currently reported, indigenous microbes which are associated with plants can improve plant health by controlling diseases and promoting plant growth. This study aims to determine the potential of fungi associated with pummelo citrus in inhibiting B. theobromae in vitro. Identification of the fungus which associates with pummelo citrus is determined by observing the cultural morphological and microscopic characteristics. The antagonist test was performed using dual culture method. The collected data was analyzed with a completely randomized design with 13 treatments and 3 replications. The results showed that there were isolates of fungi associated with pummelo citrus which were identified as Trichoderma, Aspergillus, Mucor and Fusarium genera. There were 7 isolates of fungi which have the potential to inhibit B. theobromae which were from genera Trichoderma and Aspergillus. The antagonist mechanisms that occurred in this study were competition and parasitism.

The dynamic duo of bioremediation: A case study on the efficacy of Penicellium spp and Bacillus spp

Anaerobic digestion (AD) is a biological process in which microorganisms break down organic matter with biogas. It is a series of chemical reactions during which organic material is decomposed through the metabolic pathways of naturally occurring microorganisms in an oxygen-depleted environment. Recently, anaerobic digestion (AD) has been recognized as one of the best options for treating food waste/cattle rumen mixtures since it results in two valuable final products, biogas and digestate that may be utilized for electricity production and as soil fertilizer, respectively. However, putting the digestate directly into the soil may bring environmental concerns because they contain certain pathogens and heavy metals which could be detrimental to plant and human health when consumed as food. The experimental study carried out in this project has shown that heavy metals contained in food waste/cattle rumen mixtures can be removed using indigenous microbes (Bacillus spp and Penicellium spp). From the results of the experiment carried out, it was deduced that bioremediation is effective in removing heavy metals from AD sludge. This finding is of special importance because this means that digestate can be freely used as manure without worrying about plants absorbing dangerous heavy metals which are more than their allowable limit from the soil. The use of indigenous microbes is cheap since they are readily available in the digestate.

Microbial Consortium for Polycyclic Aromatic Hydrocarbons Degradation from Petroleum Hydrocarbon Polluted Soils in Rivers State, Nigeria

The study investigated the distribution of polycyclic aromatic hydrocarbon (PAH) degraders across two different petroleum hydrocarbon-polluted sites in the Niger Delta, Nigeria, and the ability of the reconstituted indigenous consortium to utilize these PAHs. Microorganisms were isolated after sample enrichment in naphthalene and anthracene, and biosurfactant production was measured using the emulsification index technique. PAH concentrations of approximately 6000 mg/kg and 9000 mg/kg in Tombia and Bodo were higher than the Department of Petroleum Resources (DPR) intervention limit of 40 mg/kg. The pH, soil texture and high conductivity affected microbial distribution significantly. A total of 12 bacteria from the genera Bacillus, Pseudomonas, Micrococcus and 3 fungal isolates (Fusarium, Aspergillus and Penicillium) from the 2 sites were able to utilize naphthalene and/or anthracene as sole carbon source. While the Tombia site had more microorganisms capable of PAH degradation with the redox indicator 2, 6-dichlorophenol indophenol (DCPIP) (10 bacterial and 3 fungal species), two bacterial species from Bodo were able to produce biosurfactant. The findings of this study indicate that indigenous microbes in the polluted sites are catabolically active and could be further stimulated for an effective eco-friendly and green removal of PAHs from oil-polluted soils while combined.

Potential influence of microorganisms on the corrosion of carbon steel in the French high‐level long‐lived radioactive waste disposal context at 80°C

AbstractIn this study, experiments were carried out to assess the microbially influenced corrosion (MIC) risk in the context of the French high‐level radioactive waste disposal. The exposures were carried out at 80°C in different repository relevant conditions, including the presence of different cement‐grout mixtures as filling material. Biotic conditions with nutrient and nonsterile conditions with indigenous microbes added from Callovo Oxfordian clayey rock and without nutrients were considered. For biotic conditions, specific preparations of microbial inoculum were carried out from samples collected at Andra's Underground Research Laboratory and microorganisms from microbial culture collection centers. Corrosion kinetics were determined using traditional coupons and completed with real‐time corrosion sensors. Microbiological characterizations consisted of cultural approach, quantitative polymerase chain reaction, and next‐generation sequencing. The obtained results show no significant MIC and a reduced risk with the use of more alkaline filling material.

Effect of indigenous microbes on growth and blister blight disease of tea plant

Effect of indigenous microbes on growth and blister blight disease of tea plant

Low-temperature corn straw-degrading bacterial agent and moisture effects on indigenous microbes

While the in situ return of corn straw can improve soil fertility and farmland ecology, additional bacterial agents are required in low-temperature areas of northern China to accelerate straw degradation. Moisture is an important factor affecting microbial activity; however, owing to a lack of bacterial agents adapted to low-temperature complex soil environments, the effects of soil moisture on the interaction between exogenous bacterial agents and indigenous soil microorganisms remain unclear. To this end, we explored the effect of the compound bacterial agent CFF constructed using Pseudomonas putida and Acinetobacter lwoffii, developed to degrade corn straw in low-temperature soils (15 °C), on indigenous bacterial and fungal communities under dry (10% moisture content), slightly wet (20%), and wet (30%) soil-moisture conditions. The results showed that CFF application significantly affected the α-diversity of bacterial communities and changed both bacterial and fungal community structures, enhancing the correlation between microbial communities and soil-moisture content. CFF application also changed the network structure and the species of key microbial taxa, promoting more linkages among microbial genera. Notably, with an increase in soil moisture, CFF enhanced the rate of corn straw degradation by inducing positive interactions between bacterial and fungal genera and enriching straw degradation-related microbial taxa. Overall, our study demonstrates the alteration of indigenous microbial communities using bacterial agents (CFF) to overcome the limitations of indigenous microorganisms for in situ straw-return agriculture in low-temperature areas.Key points• Low-temperature and variable moisture conditions (10–30%) were compared• Soil microbial network structure and linkages between genera were altered• CFF improves straw degradation via positive interactions between soil microbes

Multifaceted plant growth-promoting traits of indigenous rhizospheric microbes against Phomopsis theae, a causal agent of stem canker in tea plants.

Phomopsis canker is one of the major devastating stem diseases that occur in tea plants caused by the fungal pathogen Phomopsis theae. Rapid development of this disease leads to a capital loss in the tea industry which demands an ecofriendly disease management strategy to control this aggressive pathogen. A total of 245 isolates were recovered from the tea rhizosphere and screened for in vitro plant growth promoting (PGP) traits and antagonism against P. theae. Among them, twelve isolates exhibited multifarious PGP traits including phytohormones, siderophore, hydrogen cyanide, salicylic acid production, phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and antifungal activity. In vitro studies on morphological, biochemical, and phylogenetic analyses classified the selected isolates as Pseudomonas fluorescens (VPF5), Bacillus subtilis (VBS3), Streptomyces griseus (VSG4) and Trichoderma viride (VTV7). Specifically, P. fluorescens VPF5 and B. subtilis VBS3 strains showed the highest level of PGP activities. On the other hand, VBS3 and VTV7 strains showed higher biocontrol efficacy in inhibiting mycelia growth and spore germination of P. theae. A detailed investigation on hydrolytic enzymes produced by antagonistic strains, which degrade the fungus cell wall, revealed that highest amount of chitinase and β-1,3- glucanase in VTV7 and VBS3 strains. Further, the key antifungal secondary metabolites from these biocontrol agents associated with suppression of P. theae were identified using gas chromatography mass spectrometry. The above study clearly recognized the specific traits in the isolated microbes, which make them good candidates as plant growth-promoting rhizobacteria (PGPR) and biocontrol agents to improve plant growth and health. However, greenhouse trials and field application of these beneficial microbes is required to further confirm their efficacy for the management of stem canker in tea cultivation.

Assessment of halotolerant bacterial and fungal consortia for augmentation of wheat in saline soils.

Adaptations of green technologies to counter abiotic stress, including salinity for crops like wheat by using halotolerant microbes, is a promising approach. The current study investigated 17 salt-affected agroecological zones from the Punjab and Sindh provinces of Pakistan to explore the potential of indigenous microbial flora, with their multiple biochemical characteristics in addition to plant growth promoting (PGP) traits, for enhanced wheat production in saline areas. Initially, 297 isolated pure bacterial colonies were screened for salt tolerance, biochemical, and PGP traits. Three bacterial strains belonging to Pantoea spp. and Erwinia rhaphontici with possession of multiple characteristics were selected for the development of the halotolerant bacterial consortium. Inoculation of two local wheat varieties, Faisalabad 2008 and Galaxy 2013, with the consortium for in vitro seed germination assay and sand microcosm experiments exhibited significant improvement of selected plant growth parameters like germination percentage and root structure. Two previously reported PGP fungal strains of Trichoderma harzianum and T. viridae were also used as fungal consortium separately for pot experiments and field trials. The pot experiments exhibited a positive correlation of consortia with metabolic viz. catalase, peroxidase, and proline and agronomical parameters including shoot length, dry weight, number of spikes, spike length, and 100 grain weight. To evaluate their performance under natural environmental conditions, field trials were conducted at three salt-affected sites. Agronomical attributes including days of flowering and maturity, flag leaf weight, length and width, shoot length, number of spikes, spike length, spike weight, number of seeds spike-1, 1,000 grain weight, and plot yield indicated the efficiency of these microbes to enhance wheat growth. Concisely, the bacterial consortium showed better performance and Faisalabad 2008 was a more resistant variety as compared to Galaxy 2013. Initial promising results indicate that further extensive research on indigenous microbes might lead to the development of Pakistan's first saline-specific biofertilizers and sustainable eco-friendly agriculture practices.

Efficient biodegradation of multiple pyrethroid pesticides by Rhodococcus pyridinivorans strain Y6 and its degradation mechanism

Pyrethroids are one of the most widely used insecticides, which have adverse biological effects and poses a serious threat to ecological environments and human health. In this study, a novel pyrethroid-degrading strain Rhodococcus pyridinivorans Y6 was isolated from activated sludge contaminated by multiple pesticides. Within 36 h, the Y6 strain was able to completely metabolize multiple pyrethroid pesticides including prallethrin, allethrin, D-cyphenothrin, fenvalerate, and beta-cypermethrin (50 mg·L−1). The results of the soil remediation indicated that the Y6 strain could effectively remove prallethrin from soil and slurry with indigenous microbes. Moreover, 16S high-throughput sequencing of the soil demonstrated that the strain Y6 had no adverse effects on the soil community structure and diversity of indigenous microbes after it entered the soil. A p-nitrophenyl esterase gene (pnbA1564) containing conserved pentapeptide motif Gly190-X-Ser192-X-Gly194 was cloned from the Y6 genome, in which Ser192 was the active center of the catalytic triad of Ser192-His416-Asp314. RT-PCR and enzyme activity analysis showed that PnbA1564 was involved in the hydrolysis of prallethrin. GC–MS results further confirmed that prallethrin could be hydrolyzed via ester bond by PnbA1564. Taken together, these original findings provide a comprehensive assessment of R. pyridinivorans strain Y6 and contribute to a better understanding of the molecular mechanism responsible for the pyrethroid biodegradation.

Strategies for Bioremediation of Soil from an Industrial Site Exposed to Chlorinated and Nitroaromatic Compounds

AbstractAs technological advances allow the development of new products, the number of synthetic chemical compounds released into the soil, surface water and groundwater increases, posing a threat to the environment. Therefore, treatability studies to improve bioremediation strategies (biostimulation and bioaugmentation) were applied to samples of soil containing nitro and chlorinated aromatic compounds from a former chemical manufacturing site in Brazil. Native microorganisms were stimulated to degrade compounds including dichloroanilines, dichloronitrobenzenes, 2‐chloronitrobenzene, and 1,2‐chlorobenzene, through oxygen exposure and pH (6.0‐8.4) and moisture content (13‐23%) adjustments. For the inoculation of soil samples, a culture enriched from site groundwater was developed. The aeration alone stimulated the indigenous microbes to degrade some of the compounds. However, reinoculation with an enriched culture and moisture content adjustment increased the attenuation rates by 3.6 and 1.4 times, respectively. The pH values in the range of 7.6 and 8.4 seem not to harm microbes' activity and moisture content higher than 16% is recommended to enhance biodegradation. Based on the findings, it is likely that natural attenuation is happening in aerobic zones at the site. Results indicate both bioremediation strategies (biostimulation and bioaugmentation through reinoculation with enriched culture mainly composed of organisms from the Diaphorobacter genus) are promising strategies to enhance bioremediation. However, considering the applicability of the strategies on a field scale, further experiments will broaden the understanding of biodegradability of compounds, such as their inhibitory effects when in higher concentration (>150 mg/kg), individually or combined.

Biogas production characteristics of lignite and related metabolic functions with indigenous microbes from different coal seams

To investigate the effects of different exogenous microorganisms on coal biomethanation and its related microbial metabolic functions. Bacterial sources were obtained from the mine water of the Xinsheng, Qinan, Fangzhuang, and Tianyuan coal mines, and lignite was utilized for conducting experiments to produce biomethane. The biomethane yield and statistical analysis based on KEGG metabolic pathways were used to assess the biomethane production potential and the difference of metabolic functions during anaerobic fermentation. The results showed that the accumulative production of biomethane in the anaerobic fermentation system with microorganisms from Qinan mine was 1.80 times, 1.18 times and 1.13 times that of the fermentation systems with other microbes from the Xinsheng, Fangzhuang and Tianyuan mine, respectively. Based on the geological environment of groundwater, it was observed that the moderate water-rich fractures in the coal seam fractures of Qinan Mine are relatively developed, which facilitates the transport of organic matter during microbial metabolism. On the other hand, the Fangzhuang and Tianyuan coal mines are situated in the groundwater runoff zone, their fracture development characteristics are comparatively lower than those of the Qinan mine. In contrast, the coal seam roof and floor of Xinsheng mine are characterized by a stable aquifer comprising thick mudstone and claystone, which presents difficulties for hydrogen-producing bacteria and methanogenic bacteria in obtaining liquid nutrients. This leads to a lower potential for methane production in the Xinsheng mine as compared to the other coal mines. The prediction based on 16S rRNA gene function showed that the microorganisms in Qinan mine had the largest abundance of annotated homologous genes involved in glycolysis, fatty acid synthesis, and methane metabolism, which had a significant positive correlation with methane production. An important observation was the absence of acetate-CoA ligase in the glycolytic pathway, which rules out the acetate-trophic pathway as a significant contributor to coal biodegradation and methanogenesis. Moreover, the abundance of genes related to the hydrogenotrophic methanogenesis pathway was found to be the highest during methane metabolism, indicating that the CO2 reduction pathway plays a significant role during the anaerobic fermentation of coal to produce biomethane.

Abiotic and Biotic Drivers of Soil Fungal Communities in Response to Dairy Manure Amendment.

Modern agriculture often relies on large inputs of synthetic fertilizers to maximize crop yield potential, yet their intensive use has led to nutrient losses and impaired soil health. Alternatively, manure amendments provide plant available nutrients, build organic carbon, and enhance soil health. However, we lack a clear understanding of how consistently manure impacts fungal communities, the mechanisms via which manure impacts soil fungi, and the fate of manure-borne fungi in soils. We assembled soil microcosms using five soils to investigate how manure amendments impact fungal communities over a 60-day incubation. Further, we used autoclaving treatments of soils and manure to determine if observed changes in soil fungal communities were due to abiotic or biotic properties, and if indigenous soil communities constrained colonization of manure-borne fungi. We found that manure amended soil fungal communities diverged from nonamended communities over time, often in concert with a reduction in diversity. Fungal communities responded to live and autoclaved manure in a similar manner, suggesting that abiotic forces are primarily responsible for the observed dynamics. Finally, manure-borne fungi declined quickly in both live and autoclaved soil, indicating that the soil environment is unsuitable for their survival. IMPORTANCE Manure amendments in agricultural systems can impact soil microbial communities via supplying growth substrates for indigenous microbes or by introducing manure-borne taxa. This study explores the consistency of these impacts on soil fungal communities and the relative importance of abiotic and biotic drivers across distinct soils. Different fungal taxa responded to manure among distinct soils, and shifts in soil fungal communities were driven largely by abiotic factors, rather than introduced microbes. This work demonstrates that manure may have inconsistent impacts on indigenous soil fungi, and that abiotic properties of soils render them largely resistant to invasion by manure-borne fungi.

Isolation Characterization and Diversity of Indigenous Pesticide Degrading Microbes from Selected Agro Ecological Zones of Malawi

Pesticide xenobiotics have a great impact on bio argumentation, bio-magnification, and environment degradation regardless of being adopted by green revolution technologies. Bioremediation is widely accepted because it’s cheap, practical at the same time environmentally friendly. Bioremediation advocates indigenous microbes use to degrade pesticides, therefore a study has been performed to show prospects of degrading microorganisms. The study isolated microbes from different agro ecological zones to assess their capacity to utilize some pesticide as sole carbon source complimented by the presence of laccase gene. Biochemical test and genetic characterization using 16S rDNA genes were used in identification. Diversified species and strains of genus Enterobacter, Klebsiella, Pseudomonas, Pantoea and Leclercia, were found to degrade cypermethrin and acetochlor but no microbe was found to degrade dimethoate. The study adds new strain of microbes involved in degradation of cypermethrin and acetochlor and also strains that that can degrade both. The study puts proposition that pest infestation in fields is a result of abundance of xenobiotic degrading microbes due to natural selection pressure not pesticide resistance of the pest.

N/S element transformation modulating lithospheric microbial communities by single-species manipulation

BackgroundThe lithospheric microbiome plays a vital role in global biogeochemical cycling, yet their mutual modulation mechanisms remain largely uncharted. Petroleum reservoirs are important lithosphere ecosystems that provide desirable resources for understanding microbial roles in element cycling. However, the strategy and mechanism of modulating indigenous microbial communities for the optimization of community structures and functions are underexplored, despite its significance in energy recovery and environmental remediation.ResultsHere we proposed a novel selective stimulation of indigenous functional microbes by driving nitrogen and sulfur cycling in petroleum reservoirs using injections of an exogenous heterocycle-degrading strain of Pseudomonas. We defined such bacteria capable of removing and releasing organically bound sulfur and nitrogen from heterocycles as “bioredox triggers”. High-throughput 16S rRNA amplicon sequencing, metagenomic, and gene transcription-level analyses of extensive production water and sandstone core samples spanning the whole oil production process clarified the microbiome dynamics following the intervention. These efforts demonstrated the feasibility of in situ N/S element release and electron acceptor generation during heterocycle degradation, shifting microbiome structures and functions and increasing phylogenetic diversity and genera engaged in sulfur and nitrogen cycling, such as Desulfovibrio, Shewanella, and Sulfurospirillum. The metabolic potentials of sulfur- and nitrogen-cycling processes, particularly dissimilatory sulfate reduction and dissimilatory nitrate reduction, were elevated in reservoir microbiomes. The relative expression of genes involved in sulfate reduction (dsrA, dsrB) and nitrate reduction (napA) was upregulated by 85, 28, and 22 folds, respectively. Field trials showed significant improvements in oil properties, with a decline in asphaltenes and aromatics, hetero-element contents, and viscosity, hence facilitating the effective exploitation of heavy oil.ConclusionsThe interactions between microbiomes and element cycling elucidated in this study will contribute to a better understanding of microbial metabolic involvement in, and response to, biogeochemical processes in the lithosphere. The presented findings demonstrated the immense potential of our microbial modulation strategy for green and enhanced heavy oil recovery.7ucoPBoC4m39tpZT7x_42NVideo Graphical

Restoration on magnetite mine waste substrates using Western Australian native plants only marginally benefited from a commercial inoculant

Post-mining landscapes often lack self-sustaining plant communities and functional belowground microbial communities. Inappropriate management of soil can hinder ecological restoration of mine sites. However, the potential role of microbial inoculants and plant nutrient-acquisition strategies in improving mined substrates and facilitating mine-site restoration remains relatively unexplored. An eight-month glasshouse experiment was conducted to test: (1) whether a commercially-available microbial inoculant was effective in restoring biological properties of mined substrates, and (2) the effect of plant nutrient-acquisition strategies on improving the chemical properties of mined substrates for the growth of native plants. There was no significant improvement in plant growth by adding a commercially-sourced microbial inoculant. Soil microbial biomass carbon and phosphorus increased significantly after plant growth (main effect of species * substrates * inoculation interaction). The non-mycorrhizal disturbance-specialist plant species Maireana georgei was effective in improving hostile conditions of the mine waste. Our results highlight that re-vegetating stockpiled topsoil using local keystone species is a desirable practice that can improve soil biological properties and benefit mine-site restoration. Commercially-available agricultural-based microbial inoculants may not be compatible for mine-site restoration using native plants, but future research using indigenous soil microbes is warranted.