Indigenous Bacteria Research Articles

Probiotic potential assessment and enzyme profiling of indigenous Lactic Acid bacteria

Probiotic potential assessment and enzyme profiling of indigenous Lactic Acid bacteria

Heavily polluted mechanic workshop soil and its phenanthrene-degrading Bacillus thuringiensis

Mechanic workshops in residential areas are sites referenced for small-scale chronic contamination with petroleum hydrocarbons (HC) and associated pollutants like heavy metals. The main aim of this study was to isolate from a mechanic workshop soil in Lagos a novel indigenous bacterium with potential for degradation of phenanthrene, a model polyaromatic compound. Gas chromatographic analysis revealed concentrations of HC (20,055 mg kg-1), lead (156.19 mg kg-1) and zinc (202.005 mg kg-1) in excess of regulatory limits in the soil. Continuous enrichment resulted in the isolation of a bacterium strain ALSL2, which was identified by 16S rRNA gene sequencing as Bacillus thuringiensis. Strain ALSL2 showed broad specificity for a range of HCs including phenanthrene, anthracene, biphenyl, dibenzothiophene, crude oil, diesel and kerosene and also showed biosurfactant production with emulsification index 55.2 %, 65.7 % and 58.7 % on crude oil, kerosene and vegetable oil respectively. The isolate showed evidence of dioxygenase activity and utilized metabolites of aromatic hydrocarbon degradation including 1-naphthol and O-phthalate. At the end of 10 days 51.45 % of phenanthrene was degraded at the rate of 7.922 mg l−1 d−1, degradation constant 0.073 d−1, and half-life 9.864 d. The corresponding values for anthracene were 69.11 %, 9.92 mg l−1 d−1., 0.11 d−1, and 5.924 d respectively. Our findings represent a remarkable addition to available indigenous bioresources with potential for application in bioremediation, and further highlight mechanic workshop soils as veritable source of such isolate.

MICP mediated by indigenous bacteria isolated from tailings for biocementation for reduction of wind erosion

MICP mediated by indigenous bacteria isolated from tailings for biocementation for reduction of wind erosion

Clostridium omnivorum sp. nov., isolated from anoxic soil under the treatment of reductive soil disinfestation.

Reductive soil disinfestation (RSD), also known as biological soil disinfestation, is a bioremediation method used to suppress soil-borne plant pathogens by stimulating the activity of indigenous anaerobic bacteria in the soil. An anaerobic bacterial strain (E14T) was isolated from an anoxic soil sample subjected to RSD treatment and then comprehensively characterized. Cells of the strain were Gram-stain-positive, curved to sigmoid, and spore-forming rods. Cells were motile with a polar flagellum. Strain E14T grew in peptone-yeast extract broth, indicating that it utilized proteinous compounds. Strain E14T was also saccharolytic and produced acetate, isobutyrate, butyrate, isovalerate and gases (H2 and CO2) as fermentation products. The strain did not decompose any of examined polysaccharides except for starch. The major cellular fatty acids of strain E14T were iso-C15:0 and iso-C15:0 DMA. The closest relative to strain E14T, based on 16S rRNA gene sequences, was Clostridium thermarum SYSU GA15002T (96.2 %) in the Clostridiaceae. Whole-genome analysis of strain E14T showed that its genome was 4.66 Mb long with a genomic DNA G+C content of 32.5 mol%. The average nucleotide identity (ANIb) between strain E14T and C. thermarum SYSU GA15002T was 69.0 %. The presence of the genes encoding glycolysis and butyrate production via the acetyl-CoA pathway was confirmed through genome analysis. Based on the obtained phylogenetic, genomic and phenotypic data, we propose that strain E14T should be assigned to the genus Clostridium in the family Clostridiaceae as Clostridium omnivorum sp. nov. The type strain is E14T (=NBRC 115133T=DSM 114974T).

Bioremediation of textile effluent using indigenous microbes

The escalating demand for clean water due to rapid industrialization underscores the urgency for effective wastewater treatment. Synthetic organic dyes, extensively used in the textile industry, pose a significant environmental threat when discharged into aquatic ecosystems. Addressing this challenge necessitates the development of sustainable methods for degrading hazardous dyes. Bioremediation emerge as a promising approach to mitigate their impact. In this study, three dye-decolorizing bacteria were isolated from textile industry effluent using selective enrichment culture. Bacillus cereus (B. cereus), Micrococcus roseus (M. roseus), and Pseudomonas aeruginosa (P. aeruginosa) were identified as potential isolates. Spectrophotometric analysis revealed P. aeruginosa to exhibit the highest decolorization efficiency (99.09 %), followed by B. cereus (85.63 %), M. roseus (80.22 %), and a mixed culture of the three isolates (78.36 %) at 37 °C. Bioremediation efficacy was confirmed under optimized conditions (0.1 % glucose, 0.05 % yeast extract, pH 7.0, and 35 °C), with physiochemical analyses of textile effluent supporting the process. These indigenous bacteria hold promise for constructing cost-effective biological systems to treat textile effluent, offering insights into effective wastewater bioremediation strategies. Exploring the monoculture and consortia of three bacterial strains on dye degradation.

Effects of ultrasound-assisted plasma-activated water washing on the inhibition of natural microorganisms on fresh-cut celery and celery quality properties.

The effects of ultrasound (US)-assisted plasma-activated water (PAW) washing (UP) on the growth of indigenous bacteria, quality properties, and microbiome of fresh-cut Apium graveolens (celery) were investigated. Among the tested treatments (UP, NaClO solution, US alone, and PAW alone), UP was the most effective in decontaminating fresh-cut celery and inhibiting the growth of natural bacteria in the celery during storage at 4 and 10°C. No significant differences were observed in the firmness, color, or sensory properties between untreated and UP-treated fresh-cut celery during storage. The proportion of Proteobacteria and Actinobacteria on UP-treated fresh-cut celery decreased after storage at 4°C for 3days, confirming the influence of UP treatment on the celery microbiome. The UP treatment induced alterations in the microbial composition of celery. These results demonstrate the potential utility of UP treatment as a novel microbial decontamination process for the preparation of fresh-cut celery products.

Textile Dye Decolorization Potential of Bacillus pumilus and Staphylococcus saprophyticus Isolated From Textile Industry Effluents

Textile dyeing industries are usually chastised for being big polluters due to the poisonous nature of most dyes, which endangers all kinds of life, including people. In this study, dye degrading bacteria were isolated from water and soil samples contaminated with textile dye taken from Batik palli in Narayanganj and the ability of five isolated bacteria including Staphylococcus saprophyticus, Bacillus pumilus, Micrococcus endophyticus, Pseudomonas mendocina, and Acinetobacter baumannii, to decolorize crystal violet (CV) dye was investigated. Among these, Bacillus pumilus decolorized 58% of CV at 250 ppm, while Staphylococcus saprophyticus decolorized 48% of CV, after 3 days of incubation at 37°C. We examined multiple temperature and pH conditions to determine the best parameters for CV dye decolorization. Bacillus pumilus boosted decolorization rates by 65.39% at 37°C and at pH 7.0, while Staphylococcus saprophyticus increased decolorization rates by 58.73%, at 37°C and at pH 5.0. Furthermore, extending the incubation period to 6 days enhanced decolorization rate in both isolates, with Bacillus pumilus increased from 58% to 65% and Staphylococcus saprophyticus increased from 48% to 58%. Nevertheless, the inclusion of co-substrates such glucose and yeast extract further boosting decolorization rate for both isolates, approximately tripling it. As a result, this study discovered indigenous bacteria capable of decolorizing CV dye, implying that they could be employed in the treatment of textile wastewater effluents. Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 50-54

Probiotic Potential and Application of Indigenous Non-Starter Lactic Acid Bacteria in Ripened Short-Aged Cheese.

There are massive sources of lactic acid bacteria (LAB) in traditional dairy products. Some of these indigenous strains could be novel probiotics with applications in human health and supply the growing needs of the probiotic industry. In this work, were analyzed the probiotic and technological properties of three Lactobacilli strains isolated from traditional Brazilian cheeses. In vitro tests showed that the three strains are safe and have probiotic features. They presented antimicrobial activity against pathogenic bacteria, auto-aggregation values around 60%, high biofilm formation properties, and a survivor of more than 65% to simulated acid conditions and more than 100% to bile salts. The three strains were used as adjunct cultures separately in a pilot-scale production of Prato cheese. After 45days of ripening, the lactobacilli counts in the cheeses were close to 8 Log CFU/g, and was observed a reduction in the lactococci counts (around -3 Log CFU/g) in a strain-dependent manner. Cheese primary and secondary proteolysis were unaffected by the probiotic candidates during the ripening, and the strains showed no lipolytic effect, as no changes in the fatty acid profile of cheeses were observed. Thus, our findings suggest that the three strains evaluated have probiotic properties and have potential as adjunct non-starter lactic acid bacteria (NSLAB) to improve the quality and functionality of short-aged cheeses.

Arsenite tolerance and removal potential of the indigenous halophilic bacterium, Halomonas elongata SEK2.

The indigenous halophilic arsenite-resistant bacterium Halomonas elongata strain SEK2 isolated from the high saline soil of Malek Mohammad hole, Lut Desert, Iran, could tolerate high concentrations of arsenate (As5+) and arsenite (As3+) up to 800 and 40 mM in the SW-10 agar medium, respectively. The isolated strain was able to tolerate considerable concentrations of other toxic heavy metals and oxyanions, including Cadmium (Cd2+), Chromate (Cr6+), lead (Pb2+), and selenite (Se4+), regarding the high salinity of the culture media (with a total salt concentration of 10% (w/v)), the tolerance potential of the isolate SEK2 was unprecedented. The bioremoval potential of the isolate SEK2 was examined through the Silver diethyldithiocarbamate (SDDC) method and demonstrated that the strain SEK2 could remove 60% of arsenite from arsenite-containing growth medium after 48 h of incubation without converting it to arsenate. The arsenite adsorption or uptake by the halophilic bacterium was investigated and substantiated through Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Energy Dispersive X-ray (EDX) analyses. Furthermore, Transmission electron microscope (TEM) analysis revealed ultra-structural alterations in the presence of arsenite that could be attributed to intracellular accumulation of arsenite by the bacterial cell. Genome sequencing analysis revealed the presence of arsenite resistance as well as other heavy metals/oxyanion resistance genes in the genome of this bacterial strain. Therefore, Halomonas elongata strain SEK2 was identified as an arsenite-resistant halophilic bacterium for the first time that could be used for arsenite bioremediation in saline arsenite-polluted environments.

Characterization of microplastic degrading bacteria isolated from the Putri Cempo landfill

Abstract Exposure to plastic in the soil causes the formation of plastic debris, which breaks down into microplastics (plastic measuring <5 mm). Microplastic pollution that occurs in ecosystems has the potential to enter the human food chain and is considered a severe threat to human health. One solution to overcome the problem of microplastic pollution is to use indigenous bacteria as natural microplastic decomposing agents. This research uses an exploratory descriptive method with soil samples from the landfill followed isolation and identify the potential of indigenous bacteria from Putri Cempo landfill to degrading microplastics. Based on the research results, two isolates could degrade microplastics, namely separates CP1 and CP2. Isolate CP1 was proven to lessen microplastics by 2.43% and isolate CP2 by 1.15%. Bacterial isolates CP1 and CP2 have the same morphological characteristics. Bacterial isolates CP1 and CP2 are gram-negative bacteria, round, cream in color, with smooth edges, shiny elevations, and bacillary cell shape. In the oxidase and O/F tests, isolate CP1 had positive results, while CP2 had negative values. Bacteria CP1 grows optimally at 37°C, pH five, while CP2 at a temperature of 27°C, pH nine, and both are tolerant to NaCl at a level of 4%.

Natural bioconversion of green waste for tropical and subtropical climates and agriculture-based regions

ABSTRACT This work aims to optimise the biotransformation upset by the high lignin content, of green wastes from urban parks and gardens, by creating optimal conditions for producing a natural and stable biofertilizer with adequate microbiological quality. The addition of other nutritive residues is a promising option, nutritious and complementary agro-industrial residues from the sugar and poultry industries were then selected. Seven formulations were tested, being inoculated by the non-pathogenic antagonist Aspergillus niger, a frequent saprophyte of tropical and subtropical climates like Morocco, to control the proliferation of potentially harmful indigenous alteration bacteria. The 15-day monitoring of efficacy and safety criteria demonstrated that it is possible to produce a nutritious biofertilizer that complies with France’s NF U44–551 standard. It had no inhibitory effect on barley crops, with performance comparable to that of a commercial fertiliser. This research provides a promising approach for sustainable management of green waste in tropical and subtropical regions.

Isolation and Characterization of Amylase Enzyme Produced by Indigenous Bacteria from Sugar Factory Waste

Isolation and Characterization of Amylase Enzyme Produced by Indigenous Bacteria from Sugar Factory Waste

Biosurfactant production by Bacillus amyloliquefaciens, characterization and its potential applications

Aim: To identify indigenous bacteria responsible for producing biosurfactants in soil contaminated by oil and to investigate their potential uses in the fields of pharmaceuticals and environmental applications. Methodology: The microorganisms of oil-contaminated soil were isolated, screened, and identified using 16S rRNA gene sequencing. Bacillus amyloliquefaciens was utilized to produce biosurfactants, and were characterized by UV, TLC, FTIR, HPTLC, and GCMS analysis. Antibacterial activity, plant growth promotion, biocompatibility, and wound healing activity of surfactant were performed. Results: Six bacterial cultures (B1 to B6) were isolated from the soil samples collected from various locations in Kerala and Tamil Nadu. Among the isolates screened for biosurfactant production, Bacillus amyloliquefaciens exhibited the highest capacity for biosurfactant production, confirmed through 16S rRNA gene sequencing. The biosurfactant produced was identified as surfactin of lipopeptide nature, characterized by various analytical techniques: UV absorption at 400 nm, TLC and HPTLC (Rf value of 0.58), FTIR (prominent peak at 3819 cm-1 corresponding to -OH groups), GCMS with a maximum retention time of 12.03. Surfactin effectively inhibited pathogenic bacteria, enhanced plant growth, was biocompatible, and enhanced the rate of cell migration towards wound scratch. Interpretation: The current study revealed that Bacillus amyloliquefaciens, isolated from oil-contaminated soil, is capable of producing biosurfactant surfactin. Additionally, it unveiled a broad spectrum of applications for surfactin, encompassing wound healing, biocompatibility, antimicrobial activity, and promotion of plant growth. Key words: Antibacterial activity, Biocompatibility, Bacillus amyloliquefaciens, Biosurfactant, Wound healing

Screening of sustainable biosurfactant produced by indigenous bacteria isolated from Egyptian oil fields for microbial enhanced oil recovery

Microbial enhanced oil recovery (MEOR) stands out as an environmentally and economically significant approach utilizing microorganisms and their bio-products to reduce residual oil, and hence improve oil recovery. Due to the pollution that synthetic surfactants entail and their very expensive costs, there is a growing necessity for clean, eco-friendly alternatives. This research focuses on exploring the potential of producing biosurfactants by indigenous bacteria isolated from Egyptian Oil Fields. Five crude oil and formation water samples were collected from four Egyptian Oil Fields located in the Western Desert (WD). Nine bacterial strains were isolated and screened for biosurfactant production using different assays, followed by the extraction and purification of crude biosurfactants. The most promising biosurfactant-producing strains that showed their ability to produce effective biosurfactant according to biosurfactant screening assays were selected for further studies and identified through 16S rRNA gene sequencing. Furthermore, core-flooding micromodel experiments were conducted to evaluate the effectiveness of these extracted biosurfactants compared to a synthetic surfactant, Sodium Dodecyl Sulfate (SDS), in improving oil recovery. Results showed that the most promising biosurfactant-producing strains that exhibited notable performance and ability to produce effective biosurfactants were namely A-LB, C-LB2, and B-YM2. Therefore, they were selected for further studies and identified through 16S rRNA gene sequencing. 16S rRNA gene sequencing results showed that namely A-LB, C-LB2, and B-YM2 were identified as Bacillus massiliigabonensis, Pseudomonas nitritolerans, and Aninetobacter seohaensis, respectively. Finally, core flooding results showed that the biosurfactant produced by Bacillus massiliigabonensis demonstrated significant performance by recovering 69.96% of additional oil, whereas 68.11% and 63.34% of additional oil were recovered using biosurfactants produced by Pseudomonas nitritolerans, and Aninetobacter seohaensis, respectively. It was also noticed that the biosurfactant produced by Bacillus massiliigabonensis demonstrated significant potential in improving oil recovery compared to the synthetic surfactant (61.78%), it outperformed 8.18% more additional oil. These findings validate the effectiveness of the produced biosurfactants over synthetic surfactants emphasizing their potential as sustainable and cost-effective alternatives for enhanced oil recovery in Egyptian oil fields.

Biodegradation of endocrine disrupting compounds from the wastewater by the immobilized indigenous bacteria

Abstract4‐tert‐octyl phenol is one of the important endrocrine‐disrupting compounds and is considered a major health hazard. A total of six isolates degraded 4‐tert‐octylphenol, and the strains Bacillus velezensis LG16 and Pseudomonas aeruginosa AC20 exhibited maximum 4‐tert‐octylphenol degradation. Co‐culture of these two strains improved 4‐tert‐octylphenol degradation from the wastewater. One variable at a time approach showed that 40°C incubation temperature, pH 8.0, and an initial 4‐tert‐octylphenol (60 mg/L) influenced biodegradation. The bacterial strains were immobilized in sodium alginate beads, and improved biodegradation was achieved. The biocatalytic process mediated by the immobilized cells was optimized by a statistical approach (two‐level full factorial design and response surface methodology). In a two‐level factorial model, 4‐tert‐octylphenol degradation varied from 1.1% to 55.2%. The 4‐tert‐octylphenol degradation was maximum at pH 6, 0.01 mg/L 4‐tert‐octylphenol, and 10 mg/L glucose with 20 g beads/L. ANOVA revealed that the designed model was statistically significant (p = 0.0310). A central composite design was used to analyze the interactive effect of significant variables and to explore the optimum conditions for 4‐tert‐octylphenol degradation by immobilized bacteria. The maximum phenol degradation was observed (97.4%) at pH 7.0, 0.06 4‐tert‐octylphenol, and 13.75 g sodium alginate beads/L. ANOVA showed that the designed model was statistically significant (p = 0.0091). The designed CCD model, the correlation coefficient value, and the lack of fit value showed that the designed CCD model was significant. The immobilized bacterial cells could more effectively degrade 4‐tert‐octylphenol than free bacterial cells. The high degradation potential indicated its application in degrading 4‐tert‐octylphenol from wastewater under optimized conditions.

Characterization of Microplastic Degrading Indigenous Bacteria from Ambon Bay Waters

Microplastic degradation by bacteria can degrade low-density polyethylene (LDPE). This study aimed to analyze the potential of Ambon Bay bacteria for microplastic degradation, the condition of microplastics after degradation, and identification of the potential for microplastic degradation. The results of isolation revealed as many as 20 bacterial isolates, which correlated with physicochemical conditions in the waters of Ambon Bay. Nine of them could degrade microplastics as indicated by the presence of a clear zone, namely KA1, KA2, KA3, KA4, KA5, KA9, KA10, KS6, and KS8. They were checked for biofilm formation, microplastic hydrophobicity, and percentage of microplastic weight reduction. Four isolates with the highest percentage of microplastic weight reduction on day 40 were KA1, KA2, KA3, and KA10 at 36.19%, 10.16%, 28.39%, and 17.07%, respectively. The results of LDPE microplastic degradation showed differences using field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM/EDS), attenuated total reflection-fourier transform infrared (ATR-FTIR), and X-ray diffraction (XRD). The bacterial isolates identified were KA1 (Bacillus cereus), KA2 (Bacillus toyonesis), KA3 (Bacillus paramycoides), and KA10 (Escherichia coli). Indigenous bacteria from the waters of Ambon Bay have the potential to degrade LDPE microplastics, which causes structural changes, decreased crystallinity, weight, and C=C groups in microplastics after degradation, with bacterial isolate KA1 identified as Bacillus cereus showing the best potential with degradation of LDPE microplastics by 36.19%.

Development of selective isolation media for detecting the genera Actinomyces and Schaalia from oral specimens containing indigenous bacteria.

To isolate specific bacteria from samples constituting the microbiota, it is essential to employ selective media that suppress the growth of resident bacteria other than specific target bacteria. Selective media for clinically important Actinomyces (including Schaalia, which was previously taxonomically classified as part of the genus Actinomyces) have been limited because they have been designed for a limited range of species within the genus and require ingredients which are difficult to prepare and handle. This study aimed to develop a selective medium [referred to as Actinomyces and Schaalia Selective Medium (ASSM)] for the isolation of a broad range of Actinomyces and Schaalia species from samples mixed with resident bacteria. The composition of ASSM includes yeast extract, agar, brain heart infusion (BHI), levofloxacin (LVFX), fosfomycin (FOM), colistin (CL) and metronidazole (MNZ). Evaluation of the medium using 24 swab samples serially collected from the roots of the teeth of a healthy individual for whom metagenome sequencing data of a saliva sample are publicly available revealed that ASSM adjusted to concentrations of LVFX 0.5 mg l-1, FOM 5 mg l-1, CL 1 mg l-1 and MNZ 2 mg l-1 and cultured anaerobically at 35 °C for 7 days enabled the isolation of Actinomyces species from 37.5 % of the samples. The inclusion of CL and MNZ in ASSM can also be useful for samples harbouring other bacterial species. The selective isolation medium is expected to contribute to studies investigating the relationship between these bacteria and their pathogenesis or disease.

Selection of endophyte and indigenous bacteria degrading textile wastewater in floating treatment wetland

Selection of endophyte and indigenous bacteria degrading textile wastewater in floating treatment wetland

High capacities of carbon capture and photosynthesis of a novel organic carbon-fixing microalgae in municipal wastewater: From mutagenesis, screening, ability evaluation to mechanism analysis

The development of wastewater treatment processes capable of reducing and fixing carbon is currently a hot topic in the wastewater treatment field. Microalgae possess a natural carbon-fixing advantage, and microalgae that can symbiotically coexist with indigenous bacteria in actual wastewater attract more significant attention. Ultraviolet (UV) mutagenesis and dissolved organic carbon (DOC) acclimation were applied to strengthen the carbon-fixing performance of microalgae in this study. The mechanisms associated with microalgal water purification ability, gene regulation at the molecular level and photosynthetic potential under different trophic modes resulting from carbon fixation and transformation were disclosed. The superior performance of Chlorella sp. MHQ2 was eventually screened out among a large number of mutants generated from 3 wild-type Chlorella strains. Results indicated that the dry cell weight of the optimal species Chlorella sp. HQ mutant MHQ2 was 1.91 times that of the wild strain in the pure algal system, more carbon from municipal wastewater (MW) were transferred to the microalgae and re-entered into the biological cycle through resource utilization. In addition, COD, NH3-N and TP removal efficiencies of MW by Chlorella sp. MHQ2 were found to increase to 95.8% (1.1-times), 96.4% (1.4-times), and 92.9% (1.2-times), respectively, under the extra DOC supply and the assistance of indigenous bacteria in the MW. In the transcriptome analysis of the logarithmic phase, the glycolytic pathway was inhibited, and the pentose phosphate pathway was mainly carried out for microalgal life activities, further promoting efficient energy utilization. Upon analysis of carbon capture capacity and photosynthetic potential in trophic mode, the addition of NaHCO3 increased the photosynthetic rate of Chlorella sp. MHQ2 in mixotrophy whereas it was attenuated in autotrophy. This study could provide a new perspective for the study of resource utilization and microalgae carbon- fixing mechanisms in the actual wastewater treatment process.

Optimal conditions for nano-emulsified vegetable oil synthesis for the biostimulation of 1,1,2-trichloroethane and vinyl chloride contaminated groundwater in bioreactors

Contamination of groundwater with chlorinated aliphatic hydrocarbons (CAHs) has become increasingly widespread. Enhanced reductive dechlorination (ERD) by emulsified vegetable oil (EVO) is an environmentally friendly, low-carbon and sustainable technology that effectively eliminates the threat from CAHs. To improve the permeability and bioavailability of EVO in the low-permeability substratum, nano-emulsified vegetable oil (nanoEVO) can be synthesized using a modified phase inversion composition method (MPIC) by increasing the emulsification temperature that reduces the shear force required for the formation of nanodroplets and the interfacial tension between the mixed phase and water. The emulsification temperature of 60 °C, the water content of 40–70%, the droplet diameter (DD) of nanoEVO prepared by MPIC is ∼200 nm, and had good monodispersion (≤0.2). The high molecular weight and low solubility of vegetable oil, and similar size of droplet make nanoEVO remains homogeneous after storage for > one year. NanoEVO can effectively biostimulate indigenous bacteria in CAHs-contaminated groundwater to dechlorinate 1,1,2-trichloroethane (1,1,2-TCA) to ethene via vinyl chloride (VC). The maximum dihaloelimination rate of 1,1,2-TCA was ∼66.06 μM·Cl−·day−1 and the maximum hydrogenolysis rate of VC was ∼35.67 μM·Cl−·day−1. NanoEVO effectively increased the relative abundance of Dehalococcoides from <0.10 to 9.61%. The abundances of Dhc 16S rRNA gene and dehalogenase gene vcrA increased by 102 and 103, respectively. Biostimulation shaped the structure of microbial communities and promoted hydrolytic acidification and anaerobic fermentation. Moreover, the syntrophic VFA-oxidizing bacteria participated in secondary fermentation and were closely correlated with H2 consumption metabolism. By providing carbon sources and maintaining an anaerobic environment with stable pH and ORP, nanoEVO biostimulated the hydrolytic acidification led by fermentative bacteria, secondary fermentation with syntrophic VFA-oxidizing bacteria and reductive dechlorination carried out by dechlorinator, thus greatly increasing the CAH-dechlorinating ability of indigenous microbial communities.