Solubilization Efficiency Research Articles

The combined Application of Iron and Phosphate Solubilizing Bacteria to enhance Wheat (Triticum aestivum L.) growth and yield

This study had the objective of evaluating the efficiency of prepared iron and phosphate biofertilizers in improving wheat growth and yield. To isolate bacteria that dissolve iron and phosphate, different soil samples were collected from the Erbil governorate, a total of eighteen iron solubilizing bacteria were selected on a modified agar medium and all isolates belonged to Pseudomonas fluorescence. Twenty-two isolates of phosphate solubilizing bacteria were recognized and referred to P. putida, P.fluorescens, and Bacillus megaterium using microscopical, cultural, physiological and molecular tests. According to iron and phosphate solubilizing efficiency test, the most efficient isolate of iron solubilizing bacteria (Pfl3) and P-solubilizin bacteria (Ppu2, Bm14) were selected for biofertilizers preparation  Local and imported iron and phosphate biofertilizers were applied in pot experiment. Most biofertilizers were significantly increased yield components of wheat plants. Maximum shoot length, root length, tillers number,1000 seed weight, spike number and yield (99.60cm, 58.95cm, 22, 38.75g. 20, 5.52 ton/ha  respectively) were recorded by incoculation with P. Flourence + P. putida +B. megatrium significantly higher than uninoculated control and treatments with imported biofertilizer. It can be concluded that local iron and phosphate solubilizing bacterial isolates can be used for Fe and P biofertilizers.  &nbsp

Oral delivery of calcitonin-ion pairs: In vivo proof of concept for a highly lipophilic counterion

Hydrophobic ion pairing and subsequent incorporation into self-emulsifying drug delivery systems (SEDDS) is a promising strategy to orally deliver hydrophilic macromolecular drugs. Within this study, hydrophobic ion pairs (HIP) between salmon calcitonin (sCT) and highly lipophilic sulfosuccinate counterions were formed and compared to frequently applied commercially available counterions. Bis(isotridecyl) sulfosuccinate resulted in HIPs of the highest lipophilicity and in significantly higher solubility in lipophilic co-solvents. Thus, bis(isotridecyl) sulfosuccinate allowed efficient solubilization of sCT in a SEDDS preconcentrate based on a lipophilic co-solvent and an indigestible lipid, but omitting hydrophilic co-solvents. In addition to the increased solubility in the lipidic matrix, markedly reduced dissociation in biorelevant media resulted in high distribution coefficients between oil droplet and FaSSGF or FaSSIF (logD) of 2.98 ± 0.12 or 2.77 ± 0.14, respectively. The composition of the lipidic matrix preserved integrity of the oil droplets after emulsification and subsequent lipolysis, allowing to fully exploit the potential of the HIP attributed to the high logD. Oral administration of the HIP-loaded SEDDS resulted in an excellent relative pharmacological activity of 13.8 ± 5.6 % measured as hypocalcaemic effect in rats.

Rhizobium Inoculation Improved the Rhizosphere P Dynamics and P Uptake Capacity of Pigeon Pea Plants Grown in Strongly Weathered Soil Only under P Fertilized Conditions

The improvement of phosphorus (P) use efficiency (PUE) is a critical problem in crop production because of phosphorus’ scarcity. Especially in strongly weathered soil with a high P fixation capacity, a low PUE generally limits plant growth. Here, in a 70-day pigeon pea cultivation pot experiment using Ultisols, we evaluated the effects of Rhizobium inoculation (−I/+I) on the plant growth, rhizosphere, bulk soil P dynamics, and plant root P acquisition characteristics, with or without P fertilization (0P: no P application; 50SSP:50 kg P ha−1 with single superphosphate). The combination of Rhizobium inoculation with P fertilization (50SSP + I) increased the plant growth, P uptake, and organic acid content per pot by 63%, 41%, and 130%, respectively, but not without P fertilization (0P + I). The labile and moderately labile inorganic P (NaHCO3-Pi and NaOH-Pi) contents were higher (55% and 44%, respectively) in the rhizosphere soil than those in the bulk soil in the 50SSP + I treatment, indicating the efficient solubilization of the applied P under the 50SSP + I treatment. The fertilized PUE was higher in the 50SSP + I treatment (26%) than that in the 50SSP−I treatment (15%). Thus, these results suggest that Rhizobium inoculation with 50SSP should stimulate plant root P acquisition characteristics, leading to the solubilization of applied P in the rhizosphere and efficient plant P uptake. In conclusion, the 50SSP + I treatment effectively improved the PUE of pigeon peas in strongly weathered soil.

Design and Optimization of Rivaroxaban-Cyclodextrin-Polymer Triple Complex Formulation with Improved Solubility.

This study aimed to ensure the convenience of administration and reproducibility of efficacy, regardless of the meal, by improving the solubility of rivaroxaban (RIV). RIV is a non-vitamin K antagonist oral anticoagulants that exhibits a coagulation effect by directly inhibiting coagulation factor Xa. However, RIV has a very low solubility; therefore, it must be administered with a meal at high doses. We used a drug- hydroxypropyl-beta-cyclodextrin (CD)-water-soluble polymer triple complex (R-C-P complex) to solubilize RIV. Using Minitab, we evaluated the effect of each factor on RIV solubility and developed an optimal R-C-P complex formulation. The amount of CD, amount of polymer, and polymer type were set as the independent variables X1, X2, and X3, respectively. RIV solubility (Y1) and dissolution rate for 45 min in pH 4.5 medium (Y2) and pH 1.2 medium (Y3) were set as response variables. The most efficient RIV solubilization effect was obtained from the composition using CD and HPMC 2208, and physicochemical properties and dissolution parameters were analyzed. RIV in the R-C-P complex was present in an amorphous form and showed high solubility. Unlike commercial products, it showed a 100% dissolution rate. The R-C-P complex formulation secured high RIV solubility and 100% release regardless of pH. The results imply that high-dose RIV can be administered regardless of the meal, reducing the risk of changing the drug effect due to the patient's administration mistake.

Influence of Different Pretreatment Methods and Conditions on the Anaerobic Digestion Efficiency of Spent Mushroom Substrate

Consumption of mushrooms has recently increased due to their health benefits; consequently, increased mushroom cultivation generates large volumes of spent mushroom substrate (SMS) and effective methods for SMS valorization are thus required. Anaerobic digestion (AD) processes SMS with minimal energy and reduces the amount of waste generated; moreover, it contributes to energy generation through biogas production. To improve the energy efficiency of AD and promote sufficient biomass pretreatment, thermal pretreatment conditions require further investigation. Here, we evaluated the pretreatment efficiency and biogas production of the SMS thermal pretreatment process, studying different pretreatment temperatures to understand the formation of SMS degradation products and the changes in AD efficiency. Particularly, mechanical and hydrothermal pretreatment (HTP) methods were employed to improve SMS biodegradability. By increasing the substrate solubilization efficiency, HTP increased the biogas yield more effectively than mechanical pretreatment. Additionally, HTP improved the substrate’s physicochemical properties and increased the reactive surface area for microorganisms by changing the substrate morphology. Further, the biodegradability of the hydrothermally pretreated SMS was higher (87.46%) than that of the mechanically pretreated SMS (61.37%). Thus, SMS could be employed in biogas production and HTP play a key role in improving the biogas yield during SMS processing.

Silkworm carotenoprotein as an efficient carotenoid extractor, solubilizer and transporter

Found in many organisms, water-soluble carotenoproteins are prospective antioxidant nanocarriers for biomedical applications. Yet, the toolkit of characterized carotenoproteins is rather limited: such proteins are either too specific binders of only few different carotenoids, or their ability to transfer carotenoids to various acceptor systems is unknown. Here, by focusing on a recently characterized recombinant ~27-kDa Carotenoid-Binding Protein from Bombyx mori (BmCBP) [Slonimskiy et al., International Journal of Biological Macromolecules 214 (2022): 664–671], we analyze its carotenoid-binding repertoire and potential as a carotenoid delivery module. We show that BmCBP forms productive complexes with both hydroxyl- and ketocarotenoids - lutein, zeaxanthin, astaxanthin, canthaxanthin and a smaller antioxidant, aporhodoxanthinone, but not with β-carotene or retinal, which defines its broad ligand specificity toward xanthophylls valuable to human health. Moreover, the His-tagged BmCBP apoform is capable of cost-efficient and scalable enrichment of xanthophylls from various crude methanolic herbal extracts. Upon carotenoid binding, BmCBP remains monomeric and shows a remarkable ability to dynamically shuttle carotenoids to biological membrane models and to unrelated carotenoproteins, which in particular makes from the cyanobacterial Orange Carotenoid Protein a blue-light controlled photoswitch. Furthermore, administration of BmCBP loaded by zeaxanthin stimulates fibroblast growth, which is attractive for cell- and tissue-based assays.

Metagenomic Influential Insights in the Formation of Biogenic Iron Hydroxysulfate Precipitates by Ferrous Oxidative Microbial Consortia

The formation of iron hydroxysulfate precipitated minerals by microbial bioleaching is an undesired dominant process because it decreases the solubilization efficiency of targeted metals. To date, the microbial role in forming these precipitated minerals is unclear. Herein, we compared two microbial community diversity (consortia M1-18 and M8-15) with the distinct formation of secondary iron minerals. In the case of M1-18, a 16S rRNA metagenomic analysis revealed a higher microbial diversity and a prevalence of Ferrimicrobium and Acidimicrobiacea. This consortium also showed a slightly higher oxidation capacity and a remarkably higher particulate precipitate capacity of secondary minerals. In contrast, the consortium M8-15 showed lower diversity and poor precipitate capacity. XRD, EDS, and FE-SEM analysis of secondary iron minerals showed that the microbial consortia promote the mineralogical formation of the secondary iron precipitates in the form of schwertmannite, an early metastable phase that can be easily transformed to jarosite.

TRANSETHOSOMES AS BREAKTHROUGH TOOL FOR CONTROLLED TRANSDERMAL DELIVERY OF DEXKETOPROFEN TROMETAMOL: DESIGN, FABRICATION, STATISTICAL OPTIMIZATION, IN VITRO, AND EX VIVO CHARACTERIZATION

Objective: Transethosomes (TEs) have introduced an emerging avenue of interest in vesicular research for transdermal delivery of drugs and can be a proper delivery system for painkillers like NSAIDS. This study aimed to formulate and characterize the potential of TE to enhance the transdermal transport of Dexketoprofen trometamol (DKT) to achieve controlled pain management compared to DKT solution. Methods: Factorial design (23) was adopted to appraise the influence of independent variables, namely, Lipoid S100 and surfactant concentrations and surfactant type (X3) on the % solubilization efficiency (% SE), vesicle size (VS), and % release efficiency (% RE). Thin film hydration was the preferred approach for preparing TEs where vesicle size, zeta potential, polydispersity index, %SE and %RE were investigated. The optimized formula was nominated and subjected to several studies. For the permeation study, optimum TE was incorporated into carbapol gel base for comparison with DKT solution. Also, an accelerated stability study was assessed for optimized formula. Results: All the prepared DKT-loaded TEs revealed acceptable VS, PDI, and ZP. The highest %SE (86.08±1.05 %) and lowest %RE (44.62±1.36 %) were observed in case of F1. The optimized formula (F1) displayed VS of 133.2±1.62 nm, PDI of 0.342±0.03 and ZP of-21.6±2.45 mV. F1 revealed enhanced skin permeation of a 2.6-fold increase compared with DKT solution. Moreover, F1 was stable upon storage and a non-significant change (P>0.05) was observed. Conclusion: DKT was successfully incorporated into vesicle carrier and can signify an alternative option for providing this therapy, bypassing the poor bioavailability and considerable adverse consequences of using the oral route besides improved patient compliance.

Biological Solubilisation of Leather Industry Waste in Anaerobic Conditions: Effect of Chromium (III) Presence, Pre-Treatments and Temperature Strategies.

Collagen-based polymers and their blends have attracted considerable interest for new materials development due to their unique combination of biocompatibility, physical and mechanical properties and durability. Leather, a modified natural biopolymer made from animal rawhide and the first synthetic collagen-based polymer known since the dawn of civilization, combines all these features. Rawhide is transformed into leather by tanning, a process in which the collagen is cross-linked with different agents to make it stronger and more durable and to prevent its decay. Research on the development of environmentally friendly procedures and sustainable materials with higher efficiency and lower costs is a rapidly growing field, and leather industry is not an exemption. Chrome-tanned and vegetable-tanned (chromium-free) shavings from the leather industry present a high content of organic matter, yet they are considered recalcitrant waste to be degraded by microbiological processes like anaerobic digestion (AD), a solid technology to treat organic waste in a circular economy framework. In this technology however, the solubilisation of organic solid substrates is a significant challenge to improving the efficiency of the process. In this context, we have investigated the process of microbial decomposition of leather wastes from the tannery industry to search for the conditions that produce optimal solubilisation of organic matter. Chrome-tanned and chromium-free leather shavings were pre-treated and anaerobically digested under different temperature ranges (thermophilic-55 °C-, intermediate-42 °C- and mesophilic-35 °C) to evaluate the effect on the solubilisation of the organic matter of the wastes. The results showed that the presence of chromium significantly inhibited the solubilization (up to 60%) in the mesophilic and intermediate ranges; this is the fastest and most efficient solubilization reached under thermophilic conditions using the chromium-free leather shaving as substrates. The most suitable temperature for the solubilization was the thermophilic regime (55 °C) for both chromium-free and chrome-tanned shavings. No significant differences were observed in the thermophilic anaerobic digestion of chromium-free shavings when a pre-treatment was applied, since the solubilisation was already high without pre-treatment. However, the pre-treatments significantly improved the solubilisation in the mesophilic and intermediate configurations; the former pre-treatment was better suited in terms of performance and cost-effectiveness compared to the thermophilic range. Thus, the solubilisation of chromium-free tannery solid wastes can be significantly improved by applying appropriate pre-treatments at lower temperature ranges; this is of utter importance when optimizing anaerobic processes of recalcitrant organic wastes, with the added benefit of substantial energy savings in the scaling up of the process in an optimised circular economy scenario.

ISOLATION AND MOLECULAR CHARACTERIZATION OF PHOSPHATE SOLUBILIZING BACTERIA FROM RHIZOSPHERIC SOILS OF TROPICAL LOWLAND RICE

Phosphate-solubilizing bacteria (PSB) can promote the dissolution of insoluble phosphorus in soil, enhancing the availability of soluble P and reducing the consumption of fertilizer and aid in sustainable agricultural development. The phosphate solubilising bacteria were isolated from the rhizospheric soils of the experimental site located in the ICAR-National Rice Research Institute's experimental farm in Cuttack, India. & the population of PSBs varied between 1-22.5 cfu/gm*104 and higher in DSR (Direct seeded rice) compared to TPR (Transplanted rice). Phosphate solubilization efficiency (PSE) of the isolates gave better result in Pikovskaya’s agar medium plates i.e. 188.9% in K6 (Kasalath, P80, DSR) rather than National Botanical Research Institute’s Phosphate growth medium (NBRIP) i.e. 73.3% for K6. The highest PSE% in C sources was found in lactose i.e. 166.7% for the isolate K9 (Kasalath, P0, DSR) and 180.0% for the isolate D17 (Dular, P80, TPR) for potassium nitrate as N source. The morphological study by staining characteristics showed that all the isolates were gram negative and cocci except D19 (Dular, P80, TPR) which was gram positive and rod shaped. Amplified fragments of oligonucleotide primers in RAPD characterization showed 51.81% polymorphism and 44.54% monomorphism. Based on dendrogram all the isolates were placed in group A except S11 (Dular, P80, TPR) which was placed in major group B showing great variation from all other isolates and group A consists of 6 minor groups in which minor group A6 was the largest containing 5 isolates i.e. Kasalath, P40, DSR (S13), Kasalath, P80, DSR (S14, S15, S16) & IR36, P40, DSR (S17).

Sulfite altered permanganate pretreatment effects on the volatile fatty acid production during sludge anaerobic fermentation

Anaerobic fermentation is a low-carbon strategy for waste activated sludge (WAS) treatment with resource recovery. This study compared the effects of potassium permanganate (PM) and calcium sulfite-assisted PM (PM/CS) pretreatment on volatile fatty acids (VFAs) production during WAS fermentation. The effects of combined PM/CS on the total VFAs production were observed to be inferior to sole PM (2689 versus 3507 mg COD/L), but PM/CS pretreatment resulted in acetate-enriched VFAs (88.2% ratio) with improved sludge dewatering. The scavenging effects of interfering compounds on free radicals, which are previously speculated for extracellular polymeric substances (EPS) disruption, and the EPS-binding effects of Ca2+ in PM/CS reactors might both restrain the effective WAS solubilization and hydrolysis efficiencies in comparison with that of PM, and thus resulted in the reduced VFAs production. Moreover, both PM and PM/CS pretreatment altered the microbial community structure and metabolic traits, which were beneficial to the VFAs generation. However, the PM/CS pretreatment was more conducive to the enrichment of acetate-producing bacteria (e.g., Proteiniclasticum and Christensenellaceae_R_7_group) and acetate-forming metabolic functions (e.g., pyruvate metabolism and propanoate and butanoate degradation). Also, methanogenesis, which is an acetate-consumption process, was remarkably inhibited in PM/CS reactor, thereby promoting acetic acid accumulation effectively. This study demonstrated the distinct effects of different PM-based pretreatment on WAS fermentation and provided guidance on the appropriate pretreatment selection for WAS disposal.

Single-cell Raman-activated sorting and cultivation (scRACS-Culture) for assessing and mining in situ phosphate-solubilizing microbes from nature

Due to the challenges in detecting in situ activity and cultivating the not-yet-cultured, functional assessment and mining of living microbes from nature has typically followed a ‘culture-first’ paradigm. Here, employing phosphate-solubilizing microbes (PSM) as model, we introduce a ‘screen-first’ strategy that is underpinned by a precisely one-cell-resolution, complete workflow of single-cell Raman-activated Sorting and Cultivation (scRACS-Culture). Directly from domestic sewage, individual cells were screened for in-situ organic-phosphate-solubilizing activity via D2O intake rate, sorted by the function via Raman-activated Gravity-driven Encapsulation (RAGE), and then cultivated from precisely one cell. By scRACS-Culture, pure cultures of strong organic PSM including Comamonas spp., Acinetobacter spp., Enterobacter spp. and Citrobacter spp., were derived, whose phosphate-solubilizing activities in situ are 90–200% higher than in pure culture, underscoring the importance of ‘screen-first’ strategy. Moreover, employing scRACS-Seq for post-RACS cells that remain uncultured, we discovered a previously unknown, low-abundance, strong organic-PSM of Cutibacterium spp. that employs secretary metallophosphoesterase (MPP), cell-wall-anchored 5′-nucleotidase (encoded by ushA) and periplasmic-membrane located PstSCAB-PhoU transporter system for efficient solubilization and scavenging of extracellular phosphate in sewage. Therefore, scRACS-Culture and scRACS-Seq provide an in situ function-based, ‘screen-first’ approach for assessing and mining microbes directly from the environment.

Formation of in-situ microemulsion and its efficiency for residual PCE removal in low temperature aquifers

Microemulsion is used extensively for enhanced oil recovery due to its efficient solubilization. Recently, in-situ microemulsion has been considered to have great potential for remediation of dense non-aqueous phase liquid contaminated aquifers. However, the temperature of aquifers is substantially below that of oilfields (30–120 °C), and the influence of temperature variation on in-situ microemulsion formation and solubilization is unclear. In this work, the efficient in-situ microemulsion for low temperature aquifers were established via the ε-β fishlike phase diagram; the solubilization capacity and size distribution of microemulsion at low temperature of about 10 °C were investigated; and the remediation efficiency of microemulsion flushing for residual tetrachloroethylene (PCE) removal was evaluated. Microemulsion precursor composition of 6.0 wt% compound surfactants (Tween80: SDS=3:2), 8.0 wt% isopropyl alcohol (IPA) and 3.0 wt% NaCl was prepared to form microemulsion with PCE in situ. The PCE apparent solubility was determined to be 80.28 g L−1 at 10 °C, which was three orders of magnitude higher than that in water at the same temperature, about 0.06 g L−1. The solubilization capacity was inversely proportional to temperature and IPA concentration, whereas proportional to Na+ concentration. The microemulsion droplets size were enlarged with the increase of IPA concentration, Na+ concentration and PCE solubilization by DLS experiments. Besides, sand column flushing using various eluents (water, micelle solution, in-situ microemulsion) was conducted to determine the removal efficiency for residual PCE. It was determined that in-situ microemulsion formulations can achieve removal efficiency of 97.1% for residual PCE, which was higher than that flushed via water and micelle solution, about 54.6% and 1.1%. In summary, the results confirm great feasibility of in-situ microemulsion for DNAPLs polluted aquifer remediation.

Chemo-Sonic Pretreatment Approach on Marine Macroalgae for Energy Efficient Biohydrogen Production

The core objective of this analysis is to implement a combination of alkaline (NaOH) and sonication pretreatment techniques to produce energy-efficient biohydrogen from the marine macroalgae Chaetomorpha antennina. Anaerobic fermentation was implemented in control, sonic solubilization (SS) and sonic alkali solubilization (SAS) pretreatment for 15 days. In control, a biohydrogen production of 40 mL H2/gCOD was obtained. The sonicator intensities varied from 10% to 90% for a period of 1 h during SS pretreatment. About 2650 mg/L SCOD release with a COD solubilization of 21% was obtained at an optimum intensity of 50% in a 30 min duration, in which 119 mL H2/gCOD biohydrogen was produced in the anaerobic fermentation. SAS pretreatment was performed by varying the pH from 8 to 12 with the optimum conditions of SS where a SCOD release of 3400 mg/L, COD solubilization efficiency of 26% and a maximum biohydrogen production of 150 mL H2/gCOD was obtained at a high pH range of 11 in the fermentation. The specific energy required by SS (9000 kJ/kgTS) was comparatively higher than SAS (4500 kJ/kg TS). SAS reduced half of the energy consumption when compared to SS. Overall, SAS pretreatment was found to be energetically favorable in a field application.

Solubilization of Mouse Sperm Chromatin for Sequencing Analyses Using a Chaperon Protein.

Sperm chromatin compaction is physiologically essential for sperm to acquire the fertility. However, this unique structure composed of protamines makes us unable to solubilize the chromatin due to its resistance to sonication and enzymes usually used for chromatin fragmentation in somatic cells. Even when intense enzymatic treatment is applied, it appears to solubilize only certain portions of sperm chromatin presumably because of the heterogeneous properties. To overcome this issue, we previously developed a method to treat the sperm with recombinant nucleoplasmin, a protamine remover in fertilized embryos, followed by sonication. The nucleoplasmin treatment dramatically increased the efficiency of sperm chromatin solubilization, while arelatively large amount of recombinant nucleoplasmin was required. Here, we describe an improvement of nucleoplasmin method with a less amount of recombinant protein and a shorter reaction time.

Isolation, Solubilization of Inorganic Phosphate, and Production of Organic Acids by Individual and Co-inoculated Microorganisms

Phosphate solubilizing microorganisms (PSMs) mineralize phosphate (PO4³−) to make phosphorous available for plant uptake. This study is designed to isolate the PSMs from the subtropical environmental samples. Total 35 bacterial and 18 fungal isolates were found to be effective P solubilizers depend on their ability of P solubilization that were determined qualitatively and quantitatively using National Botanical Research Institute Phosphorus media. Efficient PSMs that were solubilizing phosphate in maximum amount were identified as Pseudomonas aeruginosa, Serratia marcescens, Pseudomonas mosselii, Bacillus licheniformis, Bacillus subtilis, Bacillus species, Aspergillus flavus, Aspergillus foetidus, Aspergillus niger, Aspergillus tubingensis, and Penicillium chrysogenum. Among them, A. tubingensis was observed as the most efficient phosphate solubilizing strain. For the first time, combined phosphate solubilization activity of A. tubingensis with other efficient phosphate solubilizers was checked and found that A. tubingensis and P. aeruginosa acted synergistically and solubilized phosphate in increased amount. High-performance liquid chromatography results revealed that A. tubingensis produced variety of organic acids including succinic, gluconic, oxalic, and citric acids. Scanning electron microscopy results confirmed the presence of firmly attached large fungal hyphae on tri-calcium phosphate (Ca3(PO4)2). Thus, the results suggest that the use of these PSMs either single or combined as bioinoculants will help to increase the availability of soluble phosphorous.

Plant growth promoting activities of P solubilizing bacteria and their impact on disease resistance in groundnut, <em>Arachis hypogaea</em> L. against soil borne fungal pathogens

Plant growth promoting (PGP) activities of soil bacteria directly help plants in taking up the nutrients, attuning the growth hormones and indirectly safeguard by inhibiting diverse groups of fungal pathogens. In this study, we explored the native P solubilizing bacteria (PSB) isolated from the acid soils (pH < 5.5) of Odisha for selection of efficient PGPR with antifungal potential. Five PSB strainswere checked for their P solubilization efficiencies with Ca3(PO4)2,AlPO4,FePO4 and Fe3(PO4)2. The bioconversion of P by all the five strains in the broth medium followed the order Ca-P > Fe(III)-P > Fe(II)-P >Al-P. The strains interestingly showed potential plant growthpromoting properties including indole acetic acid (IAA) andsiderophore production in in vitro tests. These five strains also exhibited antifungal activities against fungal pathogens( Pythium aphanidermatum, Fusarium oxysporum, Pythium debaryanum, Thanatephorus cucumeris and Aspergillus niger )of groundnut. A field study was carried out with two of the above PSB strains [identified as Bacillus amyloliquefaciens (KT633845) and Burkholderia cepacia (KT717633)] with groundnut. Both the stains significantly influenced the plantgrowth (plant height, nodule no. and nodule dry weight) and pod yield. However, these two strains inoculated along withdoses of inorganic phosphate (SSP, single super phosphate) resulted in significantly higher pod yield as well as residual soil P.Additionally; the prevalence of both seedling mortality and plant mortality due to collar rot and stem rot were found to bereduced significantly in the inoculated plots. The findings substantiate the growth promoting ability of the two P solubilizingstrains, and thus qualifies to be used as biofertilizers either alone or as components of INM practices

Phosphate solubilization and plant growth promotion by two Pantoea strains isolated from the flowers of Hedychium coronarium L.

Phosphorus (P) is an essential macronutrient for plants and is considered as one of the limiting nutrients to plants. The majority of P in the soil is found in the form of insoluble phosphate complexes, making the P unavailable for plants. In the present study, we report two highly efficient phosphate solubilizing bacteria isolated from the closed flower ofHedychium coronariumL., a medicinal plant commonly known as Gulbakawali. Based on morphological, biochemical, and molecular characterization, the two bacterial isolates were identified as genusPantoeaand designated as HCF6 and HCF9. Both these isolates efficiently solubilize tricalcium phosphate [Ca3(PO4)2] present in National Botanical Research Institute’s Phosphate (NBRIP) medium by releasing soluble phosphate up to 2000 μg ml-1and also partially solubilize aluminium phosphate (AlPO4). HCF6 and HCF9 possess several plant growth promoting traits and were evaluated for plant growth promotion ability using sand as a growth medium. Wheat plants treated with the bacterial isolates had increased root and shoot length and plant dry mass and accumulated higher inorganic phosphate in the plant tissue suggesting their role in mobilizing soluble P from insoluble P-complexes. Overall, our findings suggest that both thesePantoeaisolates (HCF6 and HCF9) represent promising candidates as bioinoculants.

Stress-Tolerant Endophytic Isolate Priestia aryabhattai BPR-9 Modulates Physio-Biochemical Mechanisms in Wheat (Triticum aestivum L.) for Enhanced Salt Tolerance.

In efforts to improve plant productivity and enhance defense mechanisms against biotic and abiotic stresses, endophytic bacteria have been used as an alternative to chemical fertilizers and pesticides. In the current study, 25 endophytic microbes recovered from plant organs of Triticum aestivum L. (wheat) were assessed for biotic (phyto-fungal pathogens) and abiotic (salinity, drought, and heavy metal) stress tolerance. Among the recovered isolates, BPR-9 tolerated maximum salinity (18% NaCl), drought (15% PEG-6000), and heavy metals (µg mL−1): Cd (1200), Cr (1000), Cu (1000), Pb (800), and Hg (30). Based on phenotypic and biochemical characteristics, as well as 16S rDNA gene sequencing, endophytic isolate BPR-9 was recognized as Priestia aryabhattai (accession no. OM743254.1). This isolate was revealed as a powerful multi-stress-tolerant crop growth promoter after extensive in-vitro testing for plant growth-promoting attributes, nutrient (phosphate, P; potassium, K; and zinc, Zn) solubilization efficiency, extracellular enzyme (protease, cellulase, amylase, lipase, and pectinase) synthesis, and potential for antagonistic activity against important fungal pathogens viz. Alternaria solani, Rhizoctonia solani, Fusarium oxysporum, and Ustilaginoidea virens. At elevated salt levels, increases were noted in indole-3-acetic acid; siderophores; P, K, and Zn-solubilization; ACC deaminase; and ammonia synthesized by Priestia aryabhattai. Additionally, under in-vitro plant bioassays, wheat seedlings inoculated with P. aryabhattai experienced superior growth compared to non-inoculated seedlings in high salinity (0–15% NaCl) environment. Under NaCl stress, germination rate, plant length, vigor indices, and leaf pigments of wheat seedlings significantly increased following P. aryabhattai inoculation. Furthermore, at 2%-NaCl, B. aryabhattai greatly and significantly (p ≤ 0.05) decreased relative leaf water content, membrane damage, and electrolyte leakage compared with the non-inoculated control. Catalase, superoxide dismutase, and peroxidase activity increased by 29, 32, and 21%, respectively, in wheat seedlings exposed to 2% NaCl and inoculated with the bacteria. The present findings demonstrate that endophytic P. aryabhattai strains might be used in the future as a multi-stress reducer and crop growth promoter in agronomically important crops including cereals.

Coupling surfactants with ISCO for remediating of NAPLs: Recent progress and application challenges.

Non-aqueous phase liquids (NAPLs) pose a serious risk to the soil-groundwater environment. Coupling surfactants with in situ chemical oxidation (ISCO) technology is a promising strategy, which is attributed to the enhanced desorption and solubilization efficiency of NAPL contaminants. However, the complex interactions among surfactants, oxidation systems, and NAPL contaminants have not been fully revealed. This review provides a comprehensive overview on the development of surfactant-coupled ISCO technology focusing on the effects of surfactants on oxidation systems and NAPLs degradation behavior. Specifically, we discussed the compatibility between surfactants and oxidation systems, including the non-productive consumption of oxidants by surfactants, the role of surfactants in catalytic oxidation systems, and the loss of surfactants solubilization capacity during oxidation process. The effect of surfactants on the degradation behavior of NAPL contaminants is then thoroughly summarized in terms of degradation kinetics, byproducts and degradation mechanisms. This review demonstrates that it is crucial to minimize the negative effects of surfactants on NAPL contaminants oxidation process by fully understanding the interaction between surfactants and oxidation systems, which would promote the successful implementation of surfactant-coupled ISCO technology in remediation of NAPLs-contaminated sites.