Bacterial Consortium Research Articles

Carbonic Anhydrase-Mediated Phosphogypsum Degradation and Enhanced CO2 Sequestration: A Promising Sustainable Strategy for Biological Resource Utilization of Phosphogypsum.

This study continues our previous investigation of the intrinsic degradation of phosphogypsum (PG) by indigenous microorganisms on amending adequate nutrients. We aim to unravel the intricate mechanisms involved in PG biotransformation by a bacterial consortium. We isolated and characterised seven multi-metal-resistant bacterial strains from a nutrient-amended PG-contaminated microcosm and identified them through 16S rRNA gene sequencing. Primarily aerobic, gram-positive chemolithotrophs, these strains demonstrated significant heavy metal (HM) uptake and PG degradation potential.Further analysis revealed that all strains produced carbonic anhydrase (CA), while six also produced urease, which may facilitate microbial-induced carbonate precipitation (MICP). Microstructural and elemental analysis using SEM-EDX and XRD confirmed the PG bio-transformation, indicating substantial increases in carbonate concentrations and reductions in sulfate levels. The consortium, composed of seven urease and CA-producing bacterial strains, effectively degraded PG, transforming it from an acidic to an alkaline state and significantly enhancing CO2 sequestration.

Synergizing Bacillus halotolerans, Pseudomonas sihuiensis and Bacillus atrophaeus with folic acid for enhanced drought resistance in wheat by metabolites and antioxidants

Drought stress imposes a serious challenge to cultivate wheat, restricting its growth. Drought reduces the capability of plant to uptake essential nutrients. This causes stunted growth, development and yield. Traditional ways to increase wheat growth under drought stress have shortcomings. Using plant-growth-promoting rhizobacteria (PGPR) has proved feasible and eco-friendly way to enhance wheat growth even under the drought stress. Combining PGPR in consortiums further boosts up their effects. In this study, we have checked the efficacy of drought-tolerant Bacillus halotolerans, Pseudomonas sihuiensis and Bacillus atrophaeus in combination. These strains were allowed to grow on PEG 6000 with concentrations (-0.15, -0.49, -0.73 and − 1.2) Mega Pascal (MPa) alone and in combination. Furthermore, Fourier transmission infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used. Their biochemical traits such as solubilization of K, P and Zn and the synthesis of siderophore, indole acetic acid (IAA), protease, amylase, hydrogen cyanide (HCN) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase were done. In addition to this, we investigated the optimum folic acid concentration i.e 150 ppm for wheat against drought stress. We conducted a pot experiment to check the growth-enhancing and drought-mitigating effects of consortium and folic acid alone and in combination. As a result, we found a significantly increased wheat biomass, relative water content (RWC), chlorophyll content, antioxidants including glutathione reductase and total soluble sugars and protein content under all treatments. However, the combined treatment of bacterial consortium and folic acid showed maximum potential to boost wheat growth and survival even under drought. We also investigated the minerals uptake by wheat after the treatments and found maximum nutrient uptake under the co-effect of folic acid and bacterial consortium We believe this is the first study that has investigated the optimal dose of folic acid for wheat. Our research is also novel in that we seek to investigate the effects of folic acid along with a bacterial consortium comprising Bacillus halotolerans, Pseudomonas sihuiensis and Bacillus atrophaeus on wheat grown under the drought stress.

Isolation, Potential Beneficial Properties, and Assessment of Storage Stability of Direct-Fed Microbial Consortia from Wild-Type Chicken Intestine.

Direct-fed microorganisms (DFM) are recognized as an alternative to antibiotic-based growth promoters in poultry production due to their health benefits. DFM, however, should undergo rigorous safety testing to ensure they meet the criteria to be "Generally Recognized as Safe." This study assessed eight bacterial consortia (BC) isolated from the ileal and cecal intestinal regions of wild-type chickens, subjecting them to probiotic tests. Subsequently, they were spray- and freeze-dried to evaluate their storage stability for 30days. BC5-I and BC7-I, isolated from the ileum, emerged as promising DFM, displaying a high content of Lactobacillales using a selective medium and higher susceptibility to Gram-positive and Gram-negative antibiotics. These BC showed a high tolerance to temperature (> 90%), pH > 4 (88-98%), and antagonist effects against Escherichia coli and Salmonella. BC5-I exhibited superior survival in the simulated gastric conditions and satisfactory intestine mucus adhesion. Freeze-drying was the best method to obtain BC5-I and BC7-I powders, with a survival efficiency of 80.3% and 73.2%, respectively, compared to the beginning of storage. BC5-I presented the lowest cell death rate and prolonged half-life through survival storage kinetics. BC5-I only contained Lactobacillus, and Limosilactobacillus reuteri was the predominant species in liquid (78.3%) and freeze-dried (59.8%) forms. BC5-I stands out as a promising Lactobacillus-based DFM that could improve chicken intestinal health and enhance meat and egg production.

Highly efficient synthetic bacterial consortium for biodegradation of aromatic volatile organic compounds: Behavior and mechanism

Aromatic volatile organic compounds (VOCs) are prevalent pollutants in chemically contaminated sites, posing threats to ecological safety and human health. To address the challenge of achieving low-carbon, low-cost, green, and sustainable in-situ remediation at these sites, a highly efficient synthetic bacterial consortium was constructed for biodegradation of selected pollutants (i.e., benzene, toluene, ethyl benzene, m-xylene, chlorobenzene, p-chlorotoluene, and p-chlorotrifluorotoluene). Under optimized conditions, the consortium achieved a total degradation efficiency of 77%. Biodegradation of benzene, toluene, ethyl benzene, and m-xylene followed first-order kinetics, while p-chlorotoluene and p-chlorotrifluorotoluene followed zero-order kinetics. The mechanisms were analyzed using microbiome technology at genetic, protein, and metabolic levels, identifying key enzymes and differences in protein expression and related metabolites. Carbon dioxide measurements and fluorescence spectrum analysis elucidated the transformation pathways. These findings underscore the consortium’s significant potential for achieving effective, eco-friendly, and sustainable bioremediation of aromatic VOCs in chemically contaminated environments.

The Reverse Ecology-Based Approach to Design a Bacterial Consortium as Soybean Bioinoculant.

Bioinoculants traditionally rely on selecting efficient microbes from the soil with potential growth-enhancing traits for plants. However, such approaches often neglect microbe-microbe and microbe-plant interactions. In this study, we applied a reverse ecology framework to design and assess a bacterial consortium tailored for soybeans. Our analysis identified Paenibacillus polymyxa, Methylobacterium brachiatum, and Enterobacter sp. as key strains for their synergistic potential in promoting soybean growth. Computational analyses revealed that these selected strains exhibited low competitiveness and metabolic compatibility. Specifically, their complementary metabolic profiles suggested minimal competition for resources and potential for mutualistic interactions. In vitro experiments further supported these findings, demonstrating that the consortium maintained stable growth without inhibitory effects among strains. In addition, greenhouse validation experiments confirmed the efficacy of the microbial consortium in enhancing soybean growth such as root and shoot development and biomass production. Overall, this study underscores the potential of reverse ecology in optimizing microbial consortia design for bioinoculant applications.

Improved chickpea growth, physiology, nutrient assimilation and rhizoremediation of hydrocarbons by bacterial consortia.

Soil pollution by petroleum hydrocarbons (PHCs) reduces yield by changing the physico-chemical properties of soil and plants due to PHCs' biotoxicity and persistence. Thus, removing PHCs from the soil is crucial for ecological sustainability. Microbes-assisted phytoremediation is an economical and eco-friendly solution. The current work aimed to develop and use bacterial consortia (BC) for PHCs degradation and plant growth enhancement in hydrocarbon-contaminated soil. Initially, the enriched microbial cultures (that were prepared from PHCs-contaminated soils from five distinct regions) were obtained via screening through microcosm experiments. Afterward, two best microbial cultures were tested for PHCs degradation under various temperature and pH ranges. After culture optimization, isolation and characterization of bacterial strains were done to construct two BC. These constructed BC were tested in a pot experiment for hydrocarbons degradation and chickpea growth in PHCs contaminated soil. Findings revealed that PHCs exerted significant phytotoxic effects on chickpea growth and physiology when cultivated in PHCs contaminated soil, reducing agronomic and physiological traits by 13-29% and 12-43%, respectively. However, in the presence of BC, the phytotoxic impacts of PHCs on chickpea plants were reduced, resulting in up to 24 - 35% improvement in agronomic and physiological characteristics as compared to un-inoculated contaminated controls. Furthermore, the bacterial consortia boosted chickpea's nutritional absorption and antioxidant mechanism. Most importantly, chickpea plants phytoremediated 52% of the initial PHCs concentration; however, adding BC1 and BC2 with chickpea plants further increased this removal and remediated 74% and 80% of the initial PHCs concentration, respectively. In general, BC2 outperformed BC1 (with few exceptions) in promoting plant growth and PHCs elimination. Therefore, using multi-trait BC for PHCs degradation and plant growth improvement under PHCs stress may be an efficient and environmentally friendly strategy to deal with PHCs pollution and toxicity.

Ex situ and in situ decolorization of the textile dye methylene blue by a cheese whey-microbial fuel cell

ABSTRACT Methylene blue (MB) is a textile dye that can be fatal to aquatic life, plants, and human health when discharged into the environment without treatment. A cheese whey-microbial fuel cell (CW-MFC) is a device that generates electricity from the degradation of cheese whey by microbial activity. The microbial activity of the CW-MFC during electricity production was able to decolorize MB. In this study, 50 ppm of MB was used to evaluate the decolorization capability of bacteria of the CW-MFC. A bacterial consortium present in the bioanode of the CW-MFC showed good MB decolorization in both the ex situ and in situ operations. Ex situ operation performed outside the CW-MFC reactor showed 92.2% MB decolorization within 18 h, while the in situ operation conducted inside the CW-MFC reactor showed 97.1% MB decolorization within the same timeframe. The maximum decolorization performance was achieved at pH 4 and 37 °C. The treated MB exhibited very little or no toxicity in the germination, rooting, and shooting of Oryza sativa compared to the untreated MB. Thus, the CW-MFC can be used as a promising technique to decolorize and remove the toxic effects of MB-contaminated wastewater, and the treated wastewater can be applicable for irrigation purposes.

Remediation of PBDE-contaminated soil using biochar-based bacterial consortium QY2Y

Biochar-immobilized microbial technologies hold substantial promise for the remediation of environmental contaminants. However, the understanding of remediation efficiency and the operation of microbial consortia in complex soil environments using biochar as a carrier remains limited. In this study, we explored the impacts of biochar combined with bacterial consortium QY2Y (consisting of Chitinophaga sp. MH-1, Achromobacter sp. YH-1, Methylobacterium sp. ZY-1, and Sphingomonas sp. GY-1) on BDE-47 dissipation in contaminated soil, as well as its effects on soil-plant systems. The findings indicated that the immobilization of biochar and QY2Y not only stimulated the biodegradation of BDE-47 (61.50%) but also decreased the bioavailability of BDE-47, subsequently reducing the concentration of BDE-47 in the edible portion of rapeseed (Brassica napus L.) by 82.00%. In addition, the combined treatment notably increased soil pH, enhanced the physicochemical properties and nutrient conditions of the soil, and amplified soil dehydrogenase, catalase, urease, and acid phosphatase activities by 58.72%, 69.25%, 54.24%, and 74.74%, respectively. The application of biochar-based QY2Y improved the soil microbial community structure, bolstered the interspecific symbiotic and cooperative relationships, and restructured the keystone taxa. The key species microbes had direct and significant positive effects on BDE-47 degradation, soil nutrients, and soil enzyme activity. This study deepens our understanding of the potential applications of immobilized microbial consortia in treating PBDE-contaminated soils and offers guidance for the management and remediation of contaminated soils.

Continuous Fixed Bed Bioreactor for the Degradation of Textile Dyes: Phytotoxicity Assessment

This study explores a novel bioremediation approach using a continuous upflow fixed bed bioreactor with date pedicels as a biosupport material. Date pedicels offer a dual advantage: providing microbial support and potentially acting as a biostimulant due to their inherent nutrients. This research is divided into two phases: with and without microbial introduction. The bioreactor’s efficiency in removing two common textile dyes, RB19 and DR227, was evaluated under various conditions: fixed bed high, the effect of the initial concentration of the pollutant, and recycling the RB19 solution within the bioreactor. Optimization studies revealed an 83% removal yield of RB19 dye with an initial pollutant concentration of 100 mg·L−1 using activated sludge as inoculum. The bioreactor developed its own bacterial consortium without initial inoculation. Microscopic analysis confirmed the presence of a diverse microbial community, including protozoa (Aspidisca and Paramecium), nematodes, and diatoms. The bioreactor exhibited efficient removal of RB19 across a range of initial concentrations (20–100 mg/L) with similar removal efficiencies (around 65%). Interestingly, the removal efficiency for DR227 was concentration-dependent. The bioreactor demonstrated the ability to enhance the biodegradability of treated RB19 solutions. Phytotoxicity tests using watercress and lettuce seeds revealed no negative impacts on plant growth. SEM and FTIR analyses were conducted to examine the biosupport material before and after biotreatment.

Enhancement of repeated inoculation strategy with a domesticated bacterial consortium on the biodegradation of high-level crude oil in soil

Repeated inoculation of hydrocarbon degrading microbes should be powerful to improve the survival of inoculant, which is vital to achieve efficient remediation of petroleum contaminated soil. This paper aims to study the repeated inoculation (with different inoculum size and time interval) enhanced bioremediation of high-level petroleum contaminated soil with a domesticated bacterial consortium. The copy number of bacterium and alkB gene, soil enzyme activities and microbial community structure during the remediation were systematically analyzed to preliminarily reveal the mechanism of repeated inoculation affecting remediation for the first time. The results revealed that repeated inoculation remarkably improved the total petroleum hydrocarbon (TPH) removal in soil (86.5 % in HC120) compared with a single inoculation (68.9 % in HA120). The TPH removal of repeated inoculation with high inoculum size (HC) on the 60th day was close to that of once inoculation (HA) on the 120th day, suggesting that repeated inoculation led to faster degradation. Interestingly, the effect of inoculation with low dose and more times (LC120, 78.5 %) was equal to that with high dose and less times (HB120, 78.0 %), even much better than that with high dose and once inoculation (HA120). Treatment HC had a significant impact on the soil bacterial diversity and community structure, and the dominant species in the inoculants, such as Stenotrophomonas and Pseudomonas, which was low abundance in the blank group (CK), still maintained high abundance during the remediation process. The soil catalase activities and the number of alkB gene were the highest in HC. Correlation analysis implied that repeated inoculation of hydrocarbon degrading bacteria did improve the survival of inoculant, soil enzyme activities and maintain the number of degrading bacteria, thus promoting the TPH removal. These findings will facilitate the practical application of bioremediation technology to contaminated environment, which has important environmental and economic benefits.

Application of propionate-producing bacterial consortium in ruminal methanogenesis inhibited environment with bromoethanesulfonate as a methanogen direct inhibitor.

Methane production in ruminants is primarily due to the conversion of metabolic hydrogen (H2), produced during anaerobic microbial fermentation, into methane by ruminal methanogens. While this process plays a crucial role in efficiently disposes of H2, it also contributes to environmental pollution and eliminating methane production in the rumen has proven to be challenging. This study investigates the use of probiotics, specifically propionate-producing bacteria, to redirect accumulated H2 in a methane-mitigated environment. For this objective, we supplemented experimental groups with Lactiplantibacillus plantarum and Megasphaera elsdenii for the reinforced acrylate pathway (RA) and Selenomonas ruminantium and Acidipropionibacterium thoenii for the reinforced succinate pathway (RS), as well as a consortium of all four strains (CB), with the total microbial concentration at 1.0 × 1010 cells/mL. To create a methane-mitigated environment, 2-bromoethanesulfonate (BES) was added to all experimental groups at a dose of 15 mg/0.5 g of feed. BES reduced methane production by 85% in vitro, and the addition of propionate-producing bacteria with BES further decreased methane emission by up to 94% compared with the control (CON) group. Although BES did not affect the alpha diversity of the ruminal bacteriome, it reduced total volatile fatty acid production and altered beta diversity of ruminal bacteriota, indicating microbial metabolic adaptations to H2 accumulation. Despite using different bacterial strains targeting divergent metabolic pathways (RA and RS), a decrease in the dominance of the [Eubacterium] ruminantium group suggesting that both approaches may have a similar modulatory effect. An increase in the relative abundance of Succiniclasticum in the CB group suggests that propionate metabolism is enhanced by the addition of a propionate-producing bacterial consortium. These findings recommend using a consortium of propionate-producing bacteria to manage H2 accumulation by altering the rumen bacteriome, thus mitigating the negative effects of methane reduction strategies.

<i>In vitro</i> studies on the development of microbial consortia for the management of major diseases in coconut and citrus

Microbial consortia for disease suppression involve combining multiple beneficial microorganisms to enhance their effectiveness in plant disease management. In present study, development of microbial consortia for the management of major diseases in coconut and citrus was carried out using bacteria Pseudomonas fluorescens, Pseudomonas putida (striata), Bacillus subtilis and fungi – Trichoderma reesei, T. harzianum, T. asperellum against major pathogens viz. Ganoderma lucidum, Thielaviopsis paradoxa, Phytopthora palmivora, Lasiodiplodia theobromae isolated from the coconut rhizosphere, and Fusarium solani isolated from the citrus rhizosphere. The promising fungal and bacterial antagonists were identified and studied for compatibility. Non-volatile compounds of consortia inhibited the test pathogens with an increase in concentration from 10 % to 75% with fungal consortia and bacterial consortia and also with mixed consortia which is composed of bacterial consortia + fungal consortia. Superior growth suppression was recorded with mixed consortia even at 10% concentration (59.44% to 65.83%) against the test pathogens in the ascending order of L. theobromae (59.44%) T. paradoxa (63.89%), G. lucidum (65.83%), P. palmivora (63.61%) and F. solani (62.78%). A similar trend was observed in 75% concentration where inhibition observed in the order of Thielaviopsis paradoxa (90.28%), G. lucidum (89.44%), F. solani (82.50%), L. theobromae (81.94%) and P. palmivora (81.39%). Volatile effect by bacterial consortia recorded the superior inhibition on test pathogens in the order of Ganoderma (85.28%), F. solani (75.28%), T. paradoxa (71.94%), P. palmivora (71.67%) and L. theobrome (67.50%) compared to the individual bioagents. Similarly, the fungal consortia showed the superior inhibitory effect on test pathogens in the order of G. lucidum (83.25%), P. palmivora (82.50%), L. theobromae (83.06%), F. solani (80.56%) and T. paradoxa (73.61%). Since there was no zone of inhibition between the strains, the interactions between Pseudomonas and Bacillus strains of Trichoderma spp. were compatible with one another. Neem cake recorded superior CFU population from 9.43 X 106 CFU at seven days by T. asperellum. Shelf life study on mixed consortia with bacterial + fungal bioagents in talc formulation indicated that all the bacterial and fungal CFU count recorded in 106 dilution for 90 days.

Impact of Plant Growth Promoting Endophytic Bacterial Consortia on Biochemical Parameters of Maize under Moisture Stress Conditions in In vitro

Mitigation strategies based on plant–microbe interactions to increase the performance of plants under water-deficit conditions are well documented. However, little is known about a suitable consortium of bacterial inoculants and underlying physiological and enzymatic events to improve drought tolerance in maize. This study aimed to investigate the synergistic interactions among plant growth-promoting bacteria to alleviate drought-induced damages in maize. In pot culture experiment endophytic bacterial consortium inoculated treatments imposed with moisture stress (75% water holding capacity) with full dose (T9) and 75% recommended dose of fertilizers (T8) were found to excel in many plant biochemical properties when compared to un-inoculated control. For instance chlorophyll stability index T9 (138.67%) T8 (133.33%), relative water content T9 (95.20%), The N, P and K uptake was found significantly higher in T9 with 13.98 g plant-1, 3.38 g plant-1 and 17.29 g plant-1 respectively. Thus, the current research advocates the use of endophytic microbial consortium to mitigate moisture stress and to improve plant biochemical properties which ultimately enhances the plant health and yield.

Enhanced degradation of crude oil by immobilized bacterial consortium through eliminating microbial flocculation towards crude oil

Microbial degradation is considered an effective and sustainable technique for the remediation of oily sludge; thus, the acquisition of crude oil-degrading bacteria is crucial for effective bioremediation. This study introduces a novel domestication-enrichment-isolation (DEI) strategy to isolate crude oil-degrading bacteria from oily sludge. Two strains, Rhodococcus rhodochrous JS-24 (R.rh) and Gordonia cholesterolivorans JS-13 (G.ch), demonstrated the highest degradation rates of 53.7% and 34.6%, respectively, within 7 days. While no synergistic effect was observed with their combined use in free bacterial consortia, and the overall degradation rate decreased to 51.9 %, which was weaker than that of R. rh treatment alone. The decrease in degradation rate is attributed to microbial flocculation towards crude oil: most droplets of crude oil were encapsulated into spherical aggregations by G. ch, thereby hindering the contact and degradation of droplets by R. rh. In contrast, immobilization technology significantly enhanced crude oil degradation by eliminating this flocculation effect. The immobilized bacterial consortium achieved a 95.5% degradation rate, representing the highest degradation rate reported for bacterial consortia. This study reveals for the first time that the side effects of bioflocculation on crude oil degradation and provides guidance for the construction of bacterial consortium.

Photocatalytic scaffolds enhance anticancer performances of bacterial consortium AUN

Microbial metabolism and function are regulated by ambient microenvironment, yet no functional microporous materials are known to regulate anticancer activity of complex bacterial systems. Here we show that a simple scaffold-mediated bacterial culture is useful for enhancing the anticancer therapeutic abilities of a microbial consortium designated as AUN and composed of intratumoural bacteria Proteus mirabilis (A-gyo) and purple photosynthetic bacteria Rhodopseudomonas palustris (UN-gyo). Our discovery of the mechanism by which porous scaffolds influence the bacterial activities of AUN will facilitate further designs of artificial scaffold material for effective treatment against drug-resistant, triple-negative breast cancer models. A polydimethylsiloxane composite artificial scaffold encapsulating light-activatable TiO2 particularly enhanced the therapeutic outcomes of AUN in syngeneic and orthotopic models. These strong anticancer efficacies were synergistically expressed in tumours because of the potent oncolytic ability of AUN with the help of various immune cells. AUN administration to canines showed well tolerability in an exploratory study.

Synergistic biodegradation of trichloroethylene-contaminated soil using Typha angustifolia L. and an anaerobic degrading bacterial consortium

Plant-microorganism combined bioremediation is a highly efficient and environmentally sustainable method for the remediation of contaminated soils. Despite its potential, the synergistic effects of wetland plants and anaerobic microbial consortium on the removal of chlorinated hydrocarbons (CAHs) from soil remain inadequately understood. In this study, an anaerobic bacterial consortium, capable of completely dechlorinating trichloroethylene (TCE), was enriched and screened from long-term CAH-contaminated soil. Subsequently, the combined effects of the wetland plant Typha angustifolia L. and the degrading bacterial consortium on the removal of TCE from soil were investigated, along with the underlying microbial mechanisms. The results demonstrated that the bacterial consortium was able to completely convert 0.5 mM TCE to vinyl chloride (VC) within 7 days, and subsequently degrade VC to ethylene within 48 days. The integration of Typha angustifolia L. with the degrading bacterial consortium significantly enhanced both the removal and complete dechlorination of TCE from the soil compared to either treatment alone. Furthermore, this combination substantially increased the diversity and richness of soil bacterial communities, enriched dechlorinating microorganisms, and elevated the relative abundance of dehalogenating enzymes and peroxidases involved in pollutant degradation. In addition, the combination resulted in a more complex soil bacterial community, closer microbial interactions, and a more stable microbial co-occurrence network. This study extends the scope of plant-microorganism combined bioremediation for CAH- contaminated soils.

Biopriming of Solanum Lycopersicum seeds with novel root endophytic bacterial consortium retrieved from halotolerant Sundarban Mangroves to sustain growth and yield with salt resilience

Mangroves are often found in coastal areas and tropical wetlands that can withstand high salinity. We hypothesized that endophytes that are harbouring in the roots of mangrove plants may improve the innate immunity of host plants to survive naturally in saline environment. Retrieving these endophytes and sequential characterization may function as a novel bio-effector for non-host food crops as well. We focused on the integrated approach towards formulating a novel bacterial consortium. Thirty-one bacterial endophytes isolated from the roots of mangrove plants were screened for plant growth promoting potential by inoculating our model crop (Tomato). Seven most promising isolates impacting plant growth were identified. In-vitro plant growth promoting characters were also analysed. The root colonization by the isolates was confirmed by Scanning Electron Microscopy (SEM). Among the screened isolates, four of them were found to be compatible with each other when grown together and were selected to formulate a novel biostimulant consortia. The consortia treated Tomato plants exhibited superior phenological characters. In the pot experiment, plant height of the treated plants was about ≈43cm while the non-treated plants under salt stress could grow only up to a height of ≈26cm. Similarly, a total fruit yield of ≈6.8 kg was observed in case of treated plants under salt stress whereas the non-treated plants under salt stress could only produce ≈4.7 kg of fruit. This study demonstrated that the beneficial bacteria inhabiting in mangrove roots can increase the potential of conferring salt tolerance to non-host crops, thereby contributing to sustainable agriculture.

Influence of microbiota on the growth and gene expression of Clostridioides difficile in an in vitro coculture model.

Clostridioides difficile is an anaerobic, spore-forming, Gram-positive pathogenic bacterium. This study aimed to analyze the effect of two samples of healthy fecal microbiota on C. difficile gene expression and growth using an in vitro coculture model. The inner compartment was cocultured with spores of the C. difficile polymerase chain reaction (PCR)-ribotype 078, while the outer compartment contained fecal samples from donors to mimic the microbiota (FD1 and FD2). A fecal-free plate served as a control (CT). RNA-Seq and quantitative PCR confirmation were performed on the inner compartment sample. Similarities in gene expression were observed in the presence of the microbiota. After 12 h, the expression of genes associated with germination, sporulation, toxin production, and growth was downregulated in the presence of the microbiota. At 24 h, in an iron-deficient environment, C. difficile activated several genes to counteract iron deficiency. The expression of genes associated with germination and sporulation was upregulated at 24 h compared with 12 h in the presence of microbiota from donor 1 (FD1). This study confirmed previous findings that C. difficile can use ethanolamine as a primary nutrient source. To further investigate this interaction, future studies will use a simplified coculture model with an artificial bacterial consortium instead of fecal samples.

Diethyl phthalate removal in waste gas from plastic formulations by membrane biofilm reactor

Diethyl phthalate (DEP), the most extensively used plasticizer in plastic formulations, is categorized as a priority pollutant with carcinogenic, teratogenic, and mutagenic toxicity. A membrane biofilm reactor (MBfR) for diethyl phthalate removal in waste gas from plastic formulations was investigated, MBfR achieved effective DEP removal in 72 days of operation, DEP removal efficiency achieved 91.8 %. DEP hydrolyzing bacteria (Halomonas, Microbacterium, Pseudomonas, Rhodococcus) and phthalic acid (PA)-degrading bacteria (Chelativorans, Halomonas) along with protocatechuic acid-degrading bacteria (Pseudomonas, Microbacterium, Stappia, Rhodococcus, Dietzia, etc.) jointly completed the esterification, ring cleavage, and mineralization of DEP. Functional bacterial consortium formed a complex microbial symbiotic network of DEP degradation. The DEP biodegradation gene clusters, such as pht2345, ligABCIJK, and pcaGHLBCDIJF, encoded corresponding degradation enzymes to accomplish the conversion of DEP→PA, the ring cleavage of PA, and the degradation of protocatechuic acid. DEP was metabolized to PA by de-esterification and re-esterification, further degraded to hydroxyquinol by ring-cleavage before ring-opening, and then further converted into acetyl-CoA, which was eventually metabolized into CO2 and H2O by participating in the tricarboxylic acid (TCA) cycle. This provides a feasible and environmentally friendly biotechnology for the removal of diethyl phthalate in waste gas using a membrane biofilm reactor.

Assessing the effectiveness of different bacterial consortium types and varying incubation times in the bioremediation of oil sludge waste

Assessing the effectiveness of different bacterial consortium types and varying incubation times in the bioremediation of oil sludge waste