Pseudomonas Fluorescens Research Articles

Determination of Antimicrobial Activity and MIC Value of Tannic Acid Against Four Different Fish Pathogens

In this study, the antimicrobial susceptibility of Silvafeed TSP (tannic acid) obtained from chestnut tree using natural extraction method and used as a feed sweetener in aquaculture against some fish pathogens was investigated. Antimicrobial susceptibility of different concentrations of tannic acid was determined against fish pathogens that cause significant economic losses by bacteria such as Aeromonas hydrophila, Pseudomonas fluorescens, Yersinia ruckeri and Vibrio anguillarum. According to the antimicrobial test results, it was determined that all isolates to tested antibiotics were resistant to ampicillin, however, all isolates were susceptible to other antibiotics except for P. fluorescence isolate. It was determined that the P. fluorescence isolate was resistant to other antibiotics except gentamicin and doxycycline. According to the antimicrobial susceptibility test results of tannic acid against E. coli and four different fish pathogens, P. fluorescens and V. anguillarum were found to be sensitive above 125 µg/ml concentrations. In the same study, E. coli, A. hydrophila, and Y. ruckeri were found to be sensitive above 250 µg/ml concentrations. It was determined that P. fluorescens and V. anguillarum were resistant to tannic acid concentrations below 62.5 µg/ml. Moreover, E. coli, A. hydrophila, and Y. ruckeri were resistant to tannic acid concentrations below 125 µg/ml.

Effect of Bioagents in Different Formulations towards Rhizome Rot Management of Turmeric in Eastern Ghat High Land Zone of Odisha

A field experiment was conducted at High Altitude Research Station, Pottangi under Odisha University of Agriculture and Technology during the month of May to January 2018–19, 2019–2020 and 2020–21 to find out effect of bioagents in different formulations towards rhizome rot management in turmeric. Seven treatments were tested in the experiments T1: Tricho capsule (Trichoderma harzianum @ 1×106 cfu g-1) @ 1 capsule/120 l. of water. T2: GRB-35 capsule (Bacillus amyloliquefaciens @ 1×108 cfu g-1) @ 1 capsule/120 l. of water, T3: Tricho talc (T. harzianum @ 1×106 cfu g-1) powder @ 8.5 g l-1 of water, T4: GRB-35 talc powder (Bacillus amyloliquefaciens @ 1×108 cfu g-1) 8.5 g l-1 of water , T5: Tricho power liquid (Trichoderma viride @ 1×106 cfu ml-1) @ 5 ml l-1 of water, T6: Monas (Pseudomonas fluorescens @ 108 cfu ml-1) liquid @ 10 ml l-1 of water and T7: Control without any treatments. In each treatment rhizome treatment for 30 mins and basal applications of bioagents done at 45 and 90 DAS @ 5 l bed-1. Data on percent disease intensity, yield and B:C ratio were recorded at 45, 60 and 90 DAS. The lowest percent disease intensity (8.94%), highest fresh rhizome yield (21.06 t ha-1) and B:C ratio (1.72:1) was found in the treatment T5 followed by T1 with (10.33%) disease intensity, (20.57 t ha-1) yield and (1.69:1) B:C ratio.

Bio Efficacy of Bioagents against Sclerotium rolfsii: An Incitant of Stem Rot Disease in Groundnut

Aims: An experiment was carried out to know the bio efficacy of ten bio agents against Sclerotium rolfsii viz, Bacillus subtilis, Pseudomonas fluorescens, Bacillus megaterium, Bacillus velenzensis,Trichoderma longibrachiatum, Trichoderma hamatum, Trichoderma harzianum, Trichoderma afroharzianum,Trichoderma asperelloides, Trichoderma asperellum. Study Design: The experiment was carried out in Completely Randomised Design with three replications. Place and Duration of Study: During 2023-2024 at Department of Plant Pathology, College of Agriculture, Shivamogga. Methodology: The research utilized 10 different bioagents sourced from the Department of Plant Pathology at the College of Agriculture in Shimoga. Results: Statistically difference observed among the bio-agents evaluated with respect to per cent inhibition of mycelia growth of S. rolfsii. Among the fungal bioagents, the highest per cent inhibition of mycelial growth was observed in T. longibrachiatum (55.43%). Among bacterial bio-agents, Bacillus subtilis showed maximum inhibition (42.35 %). Conclusion: This study indicates that fungal bioagents are more effective than bacterial bioagents in controlling the growth of pathogen.

Surfactin conjugated ZIF-8-NH2 based MOF with the antibacterial ability against Pseudomonas fluorescens and its application in salmon preservation

Pseudomonas fluorescens is one of the most important specific spoilage organism (SSO) causing the corruption of salmon. Therefore, it is very necessary to develop efficiently antibacterial materials against Pseudomonas fluorescens. Present work successfully synthesized a novel bio-MOF named surfactin@ZIF-8-NH2 (Sur@ZIF-8-NH2) through covalent chemical reactions used in salmon preservation. The bio-MOF showed regular morphology and well thermal stability. It also exhibited excellent antibacterial activity against Pseudomonas fluorescens at low concentration (MIC = 0.0625 mg/mL, MBC = 0.25 mg/mL). The good hydrophobicity of Sur@ZIF-8-NH2 made it easier to adsorb and insert to the membrane of cells. And the electrostatic interaction between the negative charge of Sur@ZIF-8-NH2 and the positive charge of the bacterial surface could disturb the charge balance of Pseudomonas fluorescens, damaging ion channels and rupturing the cell membrane, resulting in an increase in the conductivity of the solution. At this point, the Zn2+(8.9 mg/L) released by Sur@ZIF-8-NH2 could more easily penetrate Pseudomonas fluorescens and cause the aggregation of reactive oxygen species (ROS), which further killed the cells. In addition, Sur@ZIF-8-NH2 could significantly inhibit the growth of Pseudomonas at the genus level and extend the shelf life of salmon by about 4 days. This investigation will be important for the development of the bio-MOFs used in aquatic products preservation.

Endophytic Pseudomonas fluorescens relieves intraspecific allelopathy of Atractylodes lancea by reducing ethylene transportation

BackgroundEndophytes play an important role in promoting plant growth. To date, although many reports provided insight into the function of endophytes in their hosts, few reports focus on their impact on nearby plants. Intraspecific allelopathy in plant community is common and presents a notable challenge to medicinal plant yield and productivity. Atractylodes lancea is a perennial herb that has relatively low yields due to intraspecific allelopathy. The bacterial endophyte Pseudomonas fluorescens ALEB7B has previously been found to increase essential oil content of A. lancea, but the role of ALEB7B in A. lancea allelopathy is still unknown.ResultsNoninoculated A. lancea exhibited growth retardation when it was grown in a community, which was related to ethylene-induced intraspecific allelopathy. Further experiment showed that exposing A. lancea to volatile from noninoculated A. lancea or same concentration of ethylene reduced growth of A. lancea. P. fluorescens-inoculated plants showed reduced ethylene emission and relieved growth retardation on neighboring noninoculated A. lancea. Moreover, P. fluorescens inoculation had little allelopathic effect when receivers were treated with ethylene receptor inhibitor or when emitters were treated with ethylene production inhibitor. Transcriptomic analysis revealed that endophyte ALEB7B altered transcriptional response associated with ethylene response and essential oil production in neighboring A. lancea.ConclusionsOur results demonstrated that the bacterial endophyte ALEB7B provides fitness benefits for both hosts and neighbors. The allelopathic effect on nearby plants can be alleviated by altering airborne signals, such as ethylene, in endophytic bacteria.

Feasibility of Fruit Waste-Derived Media for Microbial Culture: A Sustainable and Low-cost Approach

The present study, conducted at the College of Agriculture, Latur during 2023-2024, explores the viability of using fruit waste-derived media as a cost-effective alternative to conventional media for the growth of plant pathogens. The research focuses on the growth performance of Pseudomonas fluorescens, Fusarium oxysporum f. sp. udum, and Sclerotium rolfsii on media prepared from fruit peel of eight fruits (Banana, Pineapple, Papaya, Orange, Guava, Pomegranate, Dragon fruit, and Sapota). These fruit-based media were compared to traditional Nutrient Agar (NA) and Potato Dextrose Agar (PDA). Results revealed that Sclerotium rolfsii showed maximum growth on Papaya Dextrose Agar, while Pseudomonas fluorescens exhibited the most robust growth on Banana, Papaya and Dragon Fruit Dextrose Agar. Fusarium oxysporum f. sp. udum demonstrated the highest radial growth on Banana Dextrose Agar. The study also observed that fruit-based media significantly reduced costs compared to Potato Dextrose Agar and Nutrient Agar making them a sustainable and accessible option for microbiological research, particularly in resource-limited environments.

Computational insights into mercuric reductase from Pseudomonas fluorescens: a bioinformatic and molecular dynamics approach for mercury detoxification

Mercury (Hg) pollution poses significant threats to human health and ecosystems worldwide due to its persistence, bioaccumulation, and toxic effects. This study focuses on mercuric reductase from Pseudomonas fluorescens (UniProt ID Q51772), a key enzyme involved in detoxifying mercury through reduction to its less toxic elemental form, Hg(0). This study aims to explore the potential of this enzyme for bioremediation applications, focusing on structural insights, functional mechanisms, and biotechnological enhancements to facilitate mercury detoxification. The protein sequence of Q51772 was analyzed using bioinformatics tools to determine its structural and functional attributes. Physiochemical properties, including molecular weight, isoelectric point, and secondary structure predictions, were assessed. Virulence prediction tools confirmed the protein’s nontoxic and nonpathogenic nature. Homology modeling and docking studies provided insights into its three-dimensional structure and binding interactions with mercury substrates. Q51772 consists of 548 amino acids and belongs to the Pyridine nucleotide-disulphide oxidoreductase family, class I. It features specific domains crucial for mercury reduction, identified through Pfam and InterPro analyses. Physiochemical analysis indicated a stable protein with hydrophilic tendencies conducive to enzymatic function. Structural modeling validated by ProQ and PROCHECK confirmed the reliability of the predicted structure. Molecular docking of organic mercury compound with wild-type and mutant mercuric reductase revealed strong binding affinities, with key hydrogen bonds involving residues Gly95, Thr122, and Asp390. Mercuric reductase Q51772 from Pseudomonas fluorescens emerges as a promising candidate for bioremediation of mercury-contaminated environments. Future research should focus on optimizing its performance under diverse environmental conditions to advance sustainable solutions for mercury pollution control.

Impact of bioinoculants on growth enhancement, physicochemical characteristics, biochemical profiles, and enzymatic defense mechanisms in tomato (Lycopersicum esculentum)

The excessive use of fungicides in agriculture causes challenges like pathogen resistance, soil and water contamination, and potential health risks. Sustainable options like Pseudomonas spp. and yeast are being explored as bioinoculants to promote plant growth and inhibit fungal proliferation. 87 isolates, comprising 36 fluorescent Pseudomonas spp. and 51 yeast isolates were obtained from healthy fruits and vegetables. Yeast (YFSL) and Pseudomonas (PFSL) isolates significantly (p < 0.05) inhibited the in-vitro growth of Fusarium solani and Drechslera sp. Experiments in a screen house for 90 days used a randomized block design to study the effects of bioinoculants on plant and fruit health. Moreover, plants and fruits treated with these bioinoculants showed increased levels of salicylic acid (66.14%), total phenolic content (59.67%), chlorophyll (24.31%), carbohydrates (40.38%), phosphorus (0.24%), and antioxidant activity (90%). The treatments displayed higher levels of plant defensive enzymes, chitinase (0.09 mg/h/protein) and β-1-3-glucanase (0.093 mg/h/protein). The increased concentrations of antioxidant enzymes like SOD (0.07 U/L), POD (0.23 U/L), and APX (0.24 U/L) were also observed in the fruits of bio-inoculated plants. However., the difference in results was non-significant (P ≤ 0.05). This study demonstrates the Efficacy of bioinoculants in improving plant growth, compositional characteristics, and antioxidant activities while reducing losses in tomato plants and fruits.

Biofertilizer-mediated salt tolerance in sunflower: synergistic effects of Glomus mosseae and Pseudomonas fluorescens

Biofertilizer-mediated salt tolerance in sunflower: synergistic effects of Glomus mosseae and Pseudomonas fluorescens

Direct Discrimination and Growth Estimation of Foodborne Bacteria in Raw Meat Using Electronic Nose.

Evaluation concerning the presence of bacteria in meat products is mandatory for commercializing these goods. Although food bacteria detection is based on microbiological methods, these assays are usually laborious and time-consuming. In this paper, an electronic nose is used to differentiate Salmonella spp. (SA), Escherichia coli (EC), and Pseudomonas fluorescens (PF) inoculated in raw meat (beef, chicken, and pork) and incubated at 22 °C for 3 days. The obtained data were evaluated by principal component analysis (PCA) and different machine learning algorithms. From the graphical analysis of the PCA, on day 1, the clusters were close to each other for beef, chicken, and pork, while on days 2 and 3, more separated bacteria clusters were obtained regardless of the meat type, allowing for the discrimination of the samples for the latter days. To estimate the growth rates of the microorganisms, the distance between clusters was calculated and provided a pattern for the three bacteria, with the slowest-, moderate-, and fastest-growing being EC, SA, and PF, respectively. Concerning the machine learning algorithms, the accuracy varied from 93.8 to 100% for beef and chicken, while for pork, it varied from 75% to 100%. Thus, these results suggest that the proposed methodology based on electronic nose has the potential for the direct discrimination of bacteria in raw meat, with reduced analysis time, costs, and manipulating steps.

Efficacy of Bio-Agents in Managing Root Rot of Okra Caused by Rhizoctonia solani

Okra or lady’s finger [Abelmoschus esculentus (L.) Moench] is one of the most important summer vegetables of Rajasthan as well as India. Okra is attacked by several diseases caused by fungi and important one is root rot caused by Rhizoctonia solani Kuhn, which is an important constraint to the crop and causes significant economic losses. During present study, two bio-agents were evaluated alone and in combination Trichoderma harzianum through seed (4 g/kg) and soil (4 kg/ha) applications for two consecutive years under artificial inoculation conditions in the field. Among these, seed + soil application of Trichoderma harzianum was found most effective in reducing disease incidence (48.76%) and in increasing pod yield (13.46%) followed by seed treatment with T. harzianum + soil application of Pseudomonas fluorescens (46.41% and 12.84%, respectively). Looking to the increasing demand of organically produces in the market, root rot disease can be managed effectively with these eco-friendly approaches for supplying organically produced vegetables to fulfil the ever-increasing demand among health-conscious people.

Determining conditions for inactivation of multispecies biofilm cells by peracetic acid applying response surface methodology

Biofilms can form on various surfaces and are typically associated with multiple microbial species. Particularly in the food industry, biofilms are often a source of contamination, necessitating mitigation strategies. In this study, Response Surface Methodology (RSM) was utilized to optimize conditions for the inactivation of multispecies biofilm cells, with peracetic acid (PAA) (0.05%–0.5%), treatment time (5–30 min), and temperature (25–60 °C) as independent variables. The multispecies biofilm consisted of Gram-positive and Gram-negative bacteria previously isolated from biofilms formed in the presence of raw milk. Stainless steel coupons were immersed in reconstituted whole milk inoculated with Pseudomonas fluorescens, Rahnella inusitata, Staphylococcus aureus, and Micrococcus aloeverae. Sessile cell counts of approximately 108 CFU/cm2 were obtained after 10 days of incubation at 4 °C. The response surface model exhibited a good fit, with R2 of 0.949 and adjR2 of 0.883. All independent variables had a positive effect on the inactivation of biofilm cells. The maximum inactivation achieved was approximately 7 log (CFU/cm2), with the highest values observed at 0.5% PAA, for 30 min at 60 °C. Epifluorescence microscopy revealed that many cells in the biofilm were dead or injured after treatment at the central point (PAA = 0.275%; Time = 17.5 min; Temperature = 42.5 °C). RSM helps to predict better conditions for maximum biofilm eradication and proves to be a promising approach for monitoring the inactivation of multispecies biofilm cells, which warrants further exploration.

Bioagents and Beyond: Harnessing the Diversity of Nematophagous Microorganisms and Predators for Sustainable Management of Plant–Parasitic Nematodes

ABSTRACTThe scientific interest in using natural methods to control plant diseases and pests is significantly growing. Microorganisms and predators that feed on plant–parasitic nematodes are important in controlling these pests. Many studies show promising results in using these natural enemies to manage nematode populations. Our review identifies the most promising natural enemies for different types of nematodes. We highlight fungi such as Purpureocillium lilacinum, Metacordyceps chlamydosporia, Hirsutella rhossiliensis, Orbilia oligospora and Arthrobotrys spp., and bacteria such as Pasteuria penetrans, Bacillus subtilis and Pseudomonas fluorescens. These species show strong potential against specific nematode genera such as Meloidogyne, Heterodera, Pratylenchus and Globodera. Despite their effectiveness, several challenges hinder their widespread use. These include a lack of awareness among farmers, difficulties in mass‐producing and applying bioagents and limited research on their effectiveness in various environmental conditions. Future research should focus on overcoming these challenges. This includes improving the production and application of bioagents, educating farmers and conducting more field studies to confirm their effectiveness. By addressing these concerns, biological control can become a reliable and sustainable method for managing nematode pests in agriculture.

Integrated Control of Alternaria Blotch in Apple Orchards

ABSTRACTAn investigation of Alternaria blotch in apple orchards was conducted to evaluate the effectiveness of fungicides, plant extracts and bioagents against Alternaria mali through the development of integrated disease management strategies. Under pot conditions, potential combinations of fungicides, plant extracts and biocontrol agents for mitigating the disease were evaluated. Furthermore, polyhouse studies showed that bioagents such as Trichoderma viride, Bacillus subtilis and Pseudomonas fluorescens have disease control potential. Moreover, this research explored the impact of fungicides on the production of primary inoculum, highlighting the potential to impede conidial production by the pathogen. Over two cropping seasons, field assessments indicated the efficiency of integrated approaches in managing Alternaria blotch of apples. This study highlights the importance of reducing chemical inputs while ensuring successful disease management, offering important insights into a more sustainable approach to the management of diseases in apple orchards.

Autofluorescence-guided Removal of Bacterial Biofilms from Tissues Using Cold Atmospheric Pressure Plasma (CAP).

Cold atmospheric pressure plasma (CAP) has the potential to completely remove biofilms from surfaces. The goal of this study is to employ the autofluorescence nature of bacterial biofilms to guide the removal of these biofilms using a CAP scalpel. Pseudomonas fluorescens biofilms, which produce a green fluorescence under 405 nm UV light, were grown on 12 chicken samples. The tissue model (chicken tissue) is placed on a motorized X-Y stage with the plasma discharge device directly above the sample. Fluorescent-guided CAP treatment of biofilm regions was carried out using a 1.37 lpm Ar/H2O plasma device with 39.5 × 54 mm2 dimension and a 1 * 0.6 mm2 plasma discharge outlet with discharge speed was 1 mm/s and sample distance of 4 mm. The discharge voltage and current were 3.24 kV and 1.2 mA respectively. Results based on analysis of the fluorescent images show that 97% biofilm removal; CFU analysis confirms that up to 99.98% of the bacteria are now absent from the tissue's surface. This is the first instance of two new applications: using cold atmospheric plasma (CAP) to remove bacterial biofilms from soft tissues and employing CAP in an image-guided procedure.

PRP5 Induction by Infection of Pythium Sp. in Tomato

The Pseudomonas fluorescens isolate FP 7 was found to protect the tomato plants against soil borne fungus, Pythium aphanidermatum. The ability to induce defense proteins viz. -1,3 glucanase, peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) by this P. fluorescens isolate FP 7 against P. aphanidermatum fungus was further studied. Increased activity of PO, PPO and -1,3 glucanase were observed in plants pretreated with FP 7 isolate. Native PAGE (polyacrylamide gel electrophoresis) of PO showed the single isoform in all the treatment including the control and difference is by the increased intensity of the band in the inoculated control and FP 7 treatment in the tomato plant. Isoform analysis of the PPO showed the induction of the PPO in the P. fluorescens treated plants challenged with P. aphanidermatum. -1,3 glucanase in tomato cultivar, Co 3 with and without challenge inoculation of P. aphanidermatum, revealed changes in the isoform pattern after staining the gel with 2,3,5-triphenyl tetrazolium chloride. Moreover, higher accumulation of phenolics was noticed in plants pretreated with P. fluorescens isolate FP 7 challenged with P. aphanidermatum. The relevant function of Thaumatin like defense proteins and secondary metabolites involved in the phenylpropanoid pathway collectively contributing to enhanced resistance is discussed.

The Microbiota of the Outer Gut Mucus Layer of the Migrating Northeast Arctic Cod (Gadus morhua) as Determined by Shotgun DNA Sequencing.

Animals form functional units with their microbial communities, termed metaorganisms. Despite extensive research on some model animals, microbial diversity in many species remains unexplored. Here, we describe the taxonomic profile of the microbes from the outer gut mucus layer from the Northeast Arctic cod using a shotgun DNA sequencing approach. We focused on the mucus to determine if its microbial composition differs from that of the fecal microbiota, which could reveal unique microbial interactions and functions. Metagenomes from six individuals were analyzed, revealing three different taxonomic profiles: Type I is dominated in numbers by Pseudomonadaceae (44%) and Xanthomonadaceae (13%), Type II by Vibrionaceae (65%), and Type III by Enterobacteriaceae (76%). This stands in sharp contrast to the bacterial diversity of the transient gut content (i.e., feces). Additionally, binning of assembled reads followed by phylogenomic analyses place a high-completeness bin of Type I within the Pseudomonas fluorescens group, Type II within the Photobacterium phosphoreum clade, and Type III within the Escherichia/Shigella group. In conclusion, we describe the adherent bacterial diversity in the Northeast Arctic cod's intestine using shotgun sequencing, revealing different taxonomic profiles compared to the more homogenous transient microbiota. This suggests that the intestine contains two separate and distinct microbial populations.

Biological decolorisation of the anionic Dye Acid Blue 9 by bacterial consortium: A sustainable and ecofriendly approach for the treatment of textile wastewater

Industrialization has led to the proliferation of dye waste, posing significant environmental challenges due to the structural complexity of dyes. Various industries discharge untreated toxic waste into water bodies, posing severe environmental hazards to humans as well as aquatic ecosystem. Synthetic dyes from textiles exacerbate this issue due to their toxicity, making the management of industrial wastewater a significant environmental challenge. This study offers a potential solution by investigating the degradation of hazardous Acid Blue-9 (AB9) dye using bacterial consortium containing Pseudomonas fluorescens and Bacillus subtilis. The experiments were conducted in minimal salt media with varying concentrations of different parameters (pH, temperature, initial dye concentration, size of inoculum, carbon and nitrogen sources) used for optimization process. Using the One-Factor-At-A-Time method, the consortium in the study was able to decolorize at a noteworthy rate of decolorisation about 85–87.2 %. This rate was notably increased to around 90.02 % with the implementation of Response Surface Methodology. Additionally, the decolorisation process was further confirmed by using UV-Visible Spectroscopy and Fourier Transform InfraRed Spectroscopy. Additionally, a phytotoxicity assessment test on crops of agricultural significance supports the potential of this bacterial consortium for the bioremediation of AB9 contaminated water. The dye samples treated with bacterial consortium showed significantly higher seed germination rates (∼82.9 %), along with increased shoot (∼9.13 cm) and root lengths(∼3.01 cm), compared to the untreated samples. This promising finding suggests the potential for reusing treated water in agriculture and industry, offering a sustainable solution to water pollution.

Water-soluble chlorogenic acid-chitosan and polydatin-chitosan conjugates: antibacterial activity and inhibition of lipid and protein oxidation.

Chitosan (CS), an abundant alkaline polysaccharide, is valued for its biocompatibility, non-toxicity, and antibacterial properties. However, its limited solubility and modest antioxidant activity constrain its utility. Grafting polyphenols onto chitosan through the use of grafting reactions can enhance both the solubility and bioactivity of chitosan. Among the techniques employed, the free radical grafting method is favored for its simplicity, environmental sustainability, and its effectiveness in preserving biological activity. In this study, chlorogenic acid (CGA) and polydatin (PLD) were conjugated successfully to chitosan by a Vc/H2O2 redox system. Analytical techniques such as ultraviolet-visible (UV-visible) spectroscopy, fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and proton nuclear magnetic resonance (1H NMR) were employed to confirm the formation of covalent bonding between the polyphenol molecules and the chitosan backbone. The novel conjugates displayed superior antioxidant properties in comparison with pristine chitosan, as evidenced by their enhanced 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical, and hydroxyl radical scavenging capacities, and Fe2+ reducing power. Both CGA-CS and PLA-CS exhibited excellent lipid and protein oxidation inhibition capabilities. Furthermore, the conjugates were shown to have significant antibacterial effects against four common pathogenic bacteria: Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas putida, and Staphylococcus aureus (P < 0.05). The newly synthesized water-soluble polyphenol-chitosan conjugates demonstrated remarkable biological activity, particularly CGA-CS. This study offers new insights and a strong theoretical foundation for developing natural food preservation materials with potential applications in the food industry. © 2024 Society of Chemical Industry.

SYNERGISTIC EFFECT OF BACILLUS MUCILAGINOSUS AND PSEUDOMONAS FLUORESCENS ON THE AVAILABILITY OF SOIL POTASSIUM, GROWTH AND YIELD OF CUCURBITA PEPO L.

A field experiment was carried out at the field of Agricultural Research and Experiments Station during the season 2021-2022 in order to study the synergestic effect and compatible between Bacillus mucilaginosus and Pseudomonas fluorescens when they added as combination on potassium availability in the soil and on some plant growth characteristics and yield of Cucurbita pepo L. The experiment included four treatments B0, control , B1 addition of Bacillus mucilaginosus inoculum, B2 addition Pseudomonas fluorescens inoculum and B1 B2 addition of acombination of B1 and B2 inoculum . The experiment was conducted by using randomised complete blocks design in three replicates . The results showed that the co- inoculation with Bacillus mucilaginous and Pseudomonas fluorescens significant effect on quantity of soluble,exchangeable potassium as well as the plant height, dry weight of shoots, percentage of potassium in the shoot and in the fruits and total yield as compared with individual inoculation for any bacteria B1 or B2 which refers to positive synergestic effect. B1B2 treatment achieved the highest mean of soluble, exchangeable potassium which amounted to(0.163,0.856) cmol kg-1 soil respectively with an increase of (21.642 %, 15.676%) and (33.606%, 22.636%) of what was achieved by treatment (B1, B2) for the mean of soluble, exchangeable potassium respectively . B1B2 treatment achieved the lowest mean of( non-exchangeable and mineral) potassium which amounted to (35.280) cmol kg-1 soil.