Bacillus Mucilaginosus Research Articles

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.

Synergistic effect of rhamnolipid and Bacillus mucilaginosus on detoxification and activation of municipal solid waste incineration fly ash

In recent years, the substantial increase in municipal solid waste incineration fly ash (MSWIFA) production has made its treatment a critical issue. However, the high toxicity of MSWIFA makes its utilization still in the exploratory stage. In this study, the heavy metal leaching rate, particle size distribution and activity index of MSWIFA were tested to investigate the detoxification and activation effects of Bacillus mucilaginosus on MSWIFA by introducing rhamnolipid. The results show that the microbial treatment can greatly increase the leaching rate of heavy metals in MSWIFA and its 28-day and 90-day activity indexes, especially by the synergistic treatment. For the Bacillus mucilaginosus and rhamnolipid treated MSWIFA (BR-MSWIFA), the maximum leaching rates follow the order from high to low of 85.57% Cr, 78% Cu, 76.38% Zn, 62.78% Pb and 37.65% Mn, while having a low mass loss of less than 5%, which is important for its reuse. Moreover, compared with the untreated MSWIFA (U-MSWIFA), the average particle sizes of Bacillus mucilaginosus treated MSWIFA (B-MSWIFA) and BR-MSWIFA decrease from 8.39 μm to 7.80 μm and 4.31 μm, and the 28-day activity indexes increase from 80.19% to 101.59% and 110.61%. The effect mechanism is that rhamnolipid not only can promote the growth, reproduction, and metabolic acid production of Bacillus mucilaginosus, but also disperse the extracellular polymeric substance (EPS) and MSWIFA particles, thus increase their contact area and the bioleaching. This study provided a theoretical foundation for the harmless treatment and resource utilization of solid wastes containing heavy metals.

Synergistic Effects of Ternary Microbial Self-Healing Agent Comprising Bacillus pasteurii, Saccharomyces cerevisiae, and Bacillus mucilaginosus on Self-Healing Performance in Mortar

In order to prevent structural damage or high repair costs caused by concrete crack propagation, the use of microbial-induced CaCO3 precipitation to repair concrete cracks has been a hot topic in recent years. However, due to environmental constraints such as oxygen concentration, the width and depth of repaired cracks are seriously insufficient, which affects the further development of microbial self-healing agents. In this paper, a ternary microbial self-healing agent composed of different proportions of Bacillus pasteurii, Saccharomyces cerevisiae, and Bacillus mucilaginosus was designed, and its crack repair ability was evaluated. When the mixing ratio was 7:1:2, the cell concentration was the highest, the precipitation amount of CaCO3 was the highest, and the crystallinity of calcite crystal was the highest. Compared to the single microorganism, the mortar specimens with ternary microorganisms had the largest repair area (up to 100%) and the deepest repair depth (CaCO3 presents at 9–12 mm from the crack surface). This is because when the concrete breaks, all three microorganisms are activated by water, O2, and CO2. Saccharomyces cerevisiae and Bacillus mucilaginosus accelerated the growth of Bacillus pasteurii and more mineralized products; CaCO3 was rapidly formed and quickly filled on the crack surface. When CaCO3 seals the surface of the crack, the internal Saccharomyces cerevisiae and Bacillus mucilaginosus continue to play a role. Bacillus mucilaginosus can accelerate the dissolution of CO2 produced by the anaerobic fermentation of Saccharomyces cerevisiae and the hydrolysis of CO32−, thereby improving the repair of the crack depth direction.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ РАЗЛИЧНЫХ ВИДОВ УДОБРЕНИЙ ПРИ ВЫРАЩИВАНИИ КНЯЖЕНИКИ АРКТИЧЕСКОЙ (RUBUS ARCTICUS L.)

The objective of research is to develop a nutrition system for Arctic brake. The paper presents the results of research on growing Arctic brake (Rubus arcticus L.) on acidic light sod-podzolic soils in the natural and climatic conditions of the Kostroma Region. Two soil fertilization options were used: 1) azophoska 400 kg/ha (N60P60K60 as the main fertilizer + N30P30K30 top dressing); 2) the developed nutrition system, including the main organomineral fertilizer containing humic substances and bacterial spores (Bacillus subtillis, Bacillus mucilaginosus) and 3 top dressings with solutions of the mineral fertilizer Akvarin in May, June and September (10 %, 6 and 3 %, respectively). Local application of organomineral fertilizers at a dose of 500 kg/ha with 3 additional feedings of water-soluble mineral fertilizers of the Akvarin brand containing macro- and microelements has a beneficial effect on increasing the microbiological activity of the soil, ammonifiers by 25.8 %, phosphate-mobilizing bacteria by 39.1 %, its agrochemical indicators, inclu¬ding the content of organic matter by 0.4 %, mobile phosphorus and exchangeable potassium by 7.6–12.4 mg/kg, the survival rate of R. arcticus plants, the formation of the bush habitus, with the additional formation of partial shoots by 35 pcs/bush, the physiological activity of plants, expressed in an increase in the productivity of photosynthesis by 38 % and a significant increase in the yield of berries to 53.2 g/m2 (by 47.6 %). Expanding the possibility of forming R. arcticus plantations on acidic sod-podzolic soils will increase the occupancy rate of fallow soils and put them into operation. Production of berry products in the Kostroma Region as an ecologically safe region will provide enterprises engaged in the preparation of baby and dietary food with high-quality medicinal raw materials.

Synergistic enzymatic mechanism of lepidolite leaching enhanced by a mixture of Bacillus mucilaginosus and Bacillus circulans

Numerous studies have demonstrated that the co-leaching of ores by different silicate bacteria significantly improves the performance of bioleaching systems. Nevertheless, the mechanism of different silicate bacteria synergistically or complementarily enhanced the leaching process of lithium-containing silicate remains unclear. This study discussed the leaching impact of the combined presence of two metabolically distinct silicate bacteria on lepidolite, with the aim of comprehending the synergistic effect resulting from the presence of Bacillus mucilaginosus and Bacillus circulans in the leaching process. The results indicated that the polysaccharides and proteins secreted by bacteria-containing functional groups such as -OH and -COOH, which played an important role in the complex decomposition of ores. Organic acids played the role of acid etching and complexation. Bacillus mucilaginosus and Bacillus circulans exhibited low individual leaching efficiency, primarily due to their weak organic acid secretion. Moreover, the prolific polysaccharide production by Bacillus mucilaginosus led to bacterial aggregation, diminishing contact capability with minerals. Bacillus circulans decomposed the excessive polysaccharides produced by Bacillus mucilaginosus through enzymatic hydrolysis in the co-bioleaching process, providing later nutrient supply for both strains. The symbiosis of the two strains enhanced the synthesis and metabolic capabilities of both strains, resulting in increased organic acid secretion. In addition, protein and humic acid production by Bacillus mucilaginosus intensified, collectively enhancing the leaching efficiency. These findings suggested that the primary metabolic products secreted by different bacterial strains in the leaching process differ. The improvement in bioleaching efficiency during co-leaching was attributed to their effective synergistic metabolism. This work contributes to the construction of an efficient engineering microbial community to improve the efficiency of silicate mineral leaching, and reveals the feasibility of microbial co-culture to improve bioleaching.

The Impact of Nitrogen-Fixing Bacteria-Based Biostimulant Alone or in Combination with Commercial Inoculum on Tomato Native Rhizosphere Microbiota and Production: An Open-Field Trial.

The agricultural sector is currently encountering significant challenges due to the effects of climate change, leading to negative consequences for crop productivity and global food security. In this context, traditional agricultural practices have been inadequate in addressing the fast-evolving challenges while maintaining environmental sustainability. A possible alternative to traditional agricultural management is represented by using beneficial micro-organisms that, once applied as bioinoculants, may enhance crop resilience and adaptability, thereby mitigating the adverse effects of environmental stressors and boosting productivity. Tomato is one of the most important crops worldwide, playing a central role in the human diet. The aim of this study was to evaluate the impact of a nitrogen-fixing bacterial-based biostimulant (Azospirillum sp., Azotobacter sp., and Rhizobium sp.) in combination or not with a commercial inoculum Micomix (Rhizoglomus irregulare, Funnelliformis mosseae, Funnelliformis caledonium, Bacillus licheniformis, and Bacillus mucilaginosus) (MYC) on the native rhizosphere communities and tomato production. Bacterial populations in the different samples were characterized using an environmental metabarcoding approach. The bioinocula effect on the native rhizosphere microbiota resulted in significant variation both in alpha and beta diversity and in a specific signature associated with the presence of biostimulants.

Energy and Environmental Assessment of Bacteria-Inoculated Mineral Fertilizer Used in Spring Barley Cultivation Technologies

In the scientific literature there is a lack of information on the integrated effect of bioenriched complex mineral fertilizers in the energy and environmental aspects of spring barley production technology. The aim of this study was to validate the type of phosphorus-releasing bacteria and to carry out an energy and environmental assessment of the use of mineral fertilizers enriched with them for barley fertilization. The experimental field studies (2020–2022) were carried out in open ground on sandy loam soil in southern Lithuania. Four barley cultivation technologies (SC) were applied. Control (SC–1) did not use complex mineral fertilizers; in SC–2, 300 kg ha−1 of N5P20.5K36 fertilizer was applied. In SC–3, the same fertilizer was enriched with a bacterial inoculant (Paenibacillus azotofixans, Bacillus megaterium, Bacillus mucilaginosus, and Bacillus mycoides) at a rate of 150 kg ha−1, and in SC–4, 300 kg ha−1 of N5P20.5K36 fertilizer were applied and the same enrichment with the bacterial inoculant was carried out. The results confirmed the hypothesis that spring barley cultivation technologies using bacterial inoculants (SC–3 and SC–4) have higher mineral fertilizer efficiency than SC–2. In all three years, the bacterial inoculant had a positive effect on phosphorus fertilizer efficiency. In SC–4 (2020) it was 8%, in 2021—7%, and in 2022—even 17% higher compared to SC–2. In terms of energy balance, a significant influence of the bacterial inoculant was found. In 2020 and 2021, the energy balance of SC–4 was 10%, and in 2022, 22.8% higher compared to SC–2. The increase in fertilizer use efficiency resulted in a positive environmental impact, with greenhouse gas (GHG) emissions decreasing by 10% in 2020, 15% in 2021, and 19% in 2022 when comparing SC–4 and SC–2. The use of the tested bacterial formulations, without changing the mineral fertilizer rate, can lead to an average reduction in GHG emissions of about 15%. This study demonstrates that enriching mineral fertilizers with specific bacterial inoculants for spring barley cultivation significantly enhances phosphorus efficiency, improves energy balance, and reduces greenhouse gas emissions, underscoring the potential for bioaugmented fertilizers to optimize agricultural sustainability.

Efficiency of Bacillus mucilaginosus isolated from the soil in dissolving potassium in its microenvironment

Soil bacteria have an effective role in dissolving soil potassium. Bacillus mucilaginosus plays an effective role in dissolving potassium in the soil so that the plant may absorb it easily. The present study aimed to test the efficiency of bacteria in dissolving potassium present in the soil surrounding the roots of crops. B. mucilaginosus was isolated and diagnosed from the rhizosphere soil of Celery, Wheat, Basil and Alfalfa plants. The diagnosis included studying the isolates' culture, microscopic and biochemical characteristics. The laboratory study also included testing the efficiency of these bacterial isolates in dissolving potassium compounds in Modified Aleksandrov agar medium and estimating the dissolution coefficient. The results of isolation and identification of bacteria isolated from 19 out of 50 soil samples planted with different crops (Celery, Wheat, Basil and Alfalfa) showed that 8 isolates could dissolve potassium. The results of the microscopic examination of these eight isolates showed that they were sticky in shape, positive for Gram-staining, forming spores and the capsule, while the movement examination showed that they were positive for these tests (movement test). The biochemical tests and cultural characteristics showed that the eight isolates bear the characteristics of B. mucilaginosus. The results showed that the dissolution coefficient of potassium for the different isolates ranged between 2.28 and 1.14, while the type of sugar added to the culture medium increased the efficiency of bacterial isolates for potassium solubility. The study demonstrated the bacteria's efficiency in the rhizosphere region in dissolving potassium, which helps the plant use it easily.

Research on the decomposition mechanisms of lithium silicate ores with different crystal structures by autotrophic and heterotrophic bacteria

Ores serve as energy and nutrient sources for microorganisms. Through complex biochemical processes, microorganisms disrupt the surface structure of ores and release metal elements. However, there is limited research on the mechanisms by which bacteria with different nutritional modes act during the leaching process of different crystal structure ores. This study evaluated the leaching efficiency of two types of bacteria with different nutritional modes, heterotrophic bacterium Bacillus mucilaginosus (BM) and autotrophic bacterium Acidithiobacillus ferrooxidans (AF), on different crystal structure lithium silicate ores (chain spodumene, layered lepidolite and ring elbaite). The aim was to understand the behavioral differences and decomposition mechanisms of bacteria with different nutritional modes in the process of breaking down distorted crystal lattices of ores. The results revealed that heterotrophic bacterium BM primarily relied on passive processes such as bacterial adsorption, organic acid corrosion, and the complexation of small organic acids and large molecular polymers with metal ions. Autotrophic bacterium AF, in addition to exhibiting stronger passive processes such as organic acid corrosion and complexation, also utilized an active transfer process on the cell surface to oxidize Fe2+ in the ores for energy maintenance and intensified the destruction of ore lattices. As a result, strain AF exhibited a greater leaching effect on the ores compared to strain BM. Regarding the three crystal structure ores, their different stacking modes and proportions of elements led to significant differences in structural stability, with the leaching effect being highest for layered structure, followed by chain structure, and then ring structure. These findings indicate that bacteria with different nutritional modes exhibit distinct physiological behaviors related to their nutritional and energy requirements, ultimately resulting in different sequences and mechanisms of metal ion release from ores after lattice damage.

Enhancing soil health and nutrient cycling through soil amendments: Improving the synergy of bacteria and fungi

The synergy between bacteria and fungi is a key determinant of soil health and have a positive effect on plant development under drought conditions, with the potentially enhancing the sustainability of amending soil with natural materials. However, identifying how soil amendments influence plant growth is often difficult due to the complexity of microorganisms and their links with different soil amendment types and environmental factors. To address this, we conducted a field experiment to examine the impact of soil amendments (biochar, Bacillus mucilaginosus, Bacillus subtilis and super absorbent polymer) on plant growth. We also assessed variations in microbial community, links between fungi and bacteria, and soil available nutrients, while exploring how the synergistic effects between fungus and bacteria influenced the response of soil amendments to plant growth. This study revealed that soil amendments reduced soil bacterial diversity but increased the proportion of the family Enterobacteriaceae, Nitrosomonadaceae, and also increased soil fungal diversity and the proportion of the sum of the family Lasiosphaeriaceae, Chaetomiaceae, Pleosporaceae. Changes in soil microbial communities lead to increase the complexity of microbial co-occurrence networks. Furthermore, this heightened network complexity enhanced the synergy of soil bacteria and fungi, supporting bacterial functions related to soil nutrient cycling, such as metabolic functions and genetic, environmental, and cellular processes. Hence, the BC and BS had 3.0-fold and 0.5-fold greater root length densities than CK and apple tree shoot growth were increased by 62.14 %,50.53 % relative to CK, respectively. In sum, our results suggest that the synergistic effect of bacteria and fungi impacted apple tree growth indirectly by modulating soil nutrient cycling. These findings offer a new strategy for enhancing the quality of arable land in arid and semi-arid regions.

Effects of biofertilizers on the growth, leaf physiological indices and chlorophyll fluorescence response of spinach seedlings.

Chemcial fertilizer as the main strategy for improving the vegetable yields was excessively applied in recent years which led to progressively serious soil problems such as the soil acidification. According the situation, five different biofertilizer treatments [no fertilizer (CK), inoculations of Bacillus subtilis (Bs, T1), combination of Bs and Bacillus mucilaginosus (Bs+Bm, T2), Bs and Bacillus amyloliquefaciens (Bs+Ba, T3), and Bm+Ba (T4)] were conducted to investigate the effect of the growth, leaf physiological indices, and chlorophyll fluorescence of spinach seedlings in the growth chamber. The growth and physiological indices of the spinach seedlings attained a maximum under the T2 treatments. Under the T2 treatment, the ABS/RC (Absorption flux per RC), TR0/RC (Trapping flux per RC), and ET0/RC (Electron transport flux per RC) was significantly increased, while the DI0/RC [Dissipated energy flux per RC (at t = 0)] was decreased. The OJIP curve was improved under of the inoculations of fertilizers, and the increasing range was the largest under the T2 treatment. The leaf light response curve (LC) was also significantly increased under the T2 treatment. The plant growth characteristics [leaf length (LL), leaf weight (LW), plant height (PH)] were positively correlated with the J-I-P test chlorophyll fluorescence parameters [PIABS (Performance index for energy conservation from exciton to the reduction of intersystem electron acceptors), φP0 (Maximum quantum yield of primary photochemistry), φE0 (Quantum yield of electron transport), ψ0 (The probability that a trapped exciton moved an electron in electron transport chain further than QA-), TR0/RC, and ET0/RC] while negatively correlated with φD0 (Quantum yield of energy dissipation) and DI0/RC. The leaf physiological characteristics [SP (soluble protein concentrations), SC (soluble carbohydrate concentrations), Chl a (chlorophyll a), Chl b (chlorophyll b), Chl a+b, Chl a/b, and WP (water potential)] were positively correlated with the J-I-P test chlorophyll fluorescence parameters (PIABS, φP0, φE0, ψ0, ABS/RC, TR0/RC, and ET0/RC) while negatively correlated with φD0 and DI0/RC. These results indicated that the combination of Bs+Bm inoculations promoted the growth of the spinach and improved the adaptability of the vegetable to acid soil while Ba inoculation didn't have any effects to plants.

Impact of soil amendment using indigenous inoculants on tomato growth and yield parameters

Tomato (Lycopersicon esculentum mill) is one of the most important vegetable crops in the world. It is widely acknowledged that using composts and microbial inoculants as soil amendments, rather than industrialized fertilizer and raw manure, could improve soil nutrients, promote soil health and consequently improve crop yields. Global population increase necessitates increasing crop yields. Improvement and maintenance of soil fertility is essential via bio-augmentation in this economic recovery era. In this work, an open field experiment was conducted in other to study the "Yield Effects of Indigenous Microbial Inoculants on Tomato using autochthonous microbial consortia”. The experiment was laid in Randomized complete Block Design (RCBD) with three replicate consisted of six inoculants samples; Indigenous cultures viz; (A) Control, (B)Bacillus mucilaginosus (C) Azospirillum sp., (D) Azotobacter sp. (E) Commercial strains of the inoculants (F) Consortium of B, C and D. The various morphological features/yields parameters measured at intervals includes; no. of leaves, plant height, root length, accumulated dry matter and average fruit weight. The result shows that indigenous inoculants (F) increased tomato overall yield. This research is also of great significance for the development of management strategies for soil maintenance, environmental protection, and resource conservation in Nigeria where soil fertility is on the decrease due to over-use of land in other to achieve food security. From the result of the research, it can be concluded that soil augmentation with indigenous inoculants improves tomato morphological features and yields, hence should be preferred above their exotic commercial strain counterparts because of cost of importation/indigenous product development and GDP growth.

Response of Bacillus megaterium and Bacillus mucilaginosus Strains on Yield and Quality of Soybean

At present due to continuous use of phosphatic and potassic fertilizers a deposits of these nutrient have increased in the soil of studied area, and Bacillus megaterium and Bacillus mucilaginosus solubilize/mobilize P and K in the soil, thus, for increasing yield and quality of soybean, an experiment was planned with the aim to investigate the response of Bacillus megaterium and Bacillus mucilaginosus strains on yield and quality of soybean [Glycine max (L.) Merrill.] at All India Coordinated Research Project (AICRP) on Integrated Farming System Research at College of Agriculture, Indore, Madhya Pradesh, India during kharif, 2019 & 20. The research was conducted in randomized block design (RBD) with 8 treatments, viz. Control with 75% RDF (T1), Control with 100% RDF (T2), 75% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas seed treatment (T3), 100% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas seed treatment (T4), 75% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas foliar application at 30 and 45 DAS (T5), 100% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas foliar application at 30 and 45 DAS (T6), 75% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas seed treatment + foliar application of Bacillus megaterium and Bacillus mucilaginosus strainsat 30 and 45 DAS (T7) and 100% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas seed treatment + foliar application of Bacillus megaterium and Bacillus mucilaginosus strainsat 30 and 45 DAS (T8). The seed yield (1139 kg ha-1) of soybean increased to the tune of 14.26 and 19.72 per cent with application of 100% RDF with Bacillus megaterium and Bacillus mucilaginosus strainsas seed treatment + foliar application of Bacillus megaterium and Bacillus mucilaginosus strains (T8) at 30 and 45 DAS compared to control (786 kg ha-1). Among all the treatments, yield attributes such as pods count plant-1 (29.66), seeds count pod-1 (3.36) and seed yield plant-1 (13.17) were observed highest with T8 at 30 and 45 DAS.

Lithium extraction from typical lithium silicate ores by two bacteria with different metabolic characteristics: Experiments, mechanism and significance

Microorganisms obtain inorganic nutrients or energy from specific minerals to selectively weather minerals, but few studies on the differences in metabolic components of different functional bacteria lead to different weathering effects. This study evaluated the leaching effects of two bacteria with distinct metabolic characteristics on lithium silicate minerals with different structures. We aimed to understand the microscopic mechanism of crystal destruction of lithium silicate minerals with different structures under the action of microorganisms. The results showed that the metabolites produced by an acid producing silicate strain Raoultella sp. Z107 (strain Z107) had a high content of organic acids, among which lactic acid was up to about 11 g/L. Bacillus mucilaginosus 21,699 (strain BM) secreted capsular polysaccharide with a high content of 14.84 mg/L. The metabolic activities of the two strains were significantly different. Through the analysis of the leaching residue, it was found that the lithium silicate minerals were acid etched, interlayer domains expanded, crystallinity decreased, and metal bonds were broken under the action of bacteria. The dissolution of lithium silicate minerals by bacteria is a combination of bacterial adsorption, organic acid corrosion, and complexation of small molecular organic acids and macromolecular polymers with metal ions. The acid erosion and complexation effects of organic acids are greater than the single complexation of capsular polysaccharides, and the layered lepidolite is more likely to be decomposed by the weathering of bacterial metabolites than the chain structure spodumene. These results indicate that the diversity of metabolic activity of bacteria from different sources and the sequence and decomposition mechanism of metal ions released from minerals after lattice destruction are also different. Microorganisms decompose minerals for energy and nutrients, and eventually become the main players in the transformation of elements in biogeology.

Influence of Chemical, Organic, and Biological Silicon Fertilization on Physiological Studies of Egyptian Japonica Green Super Rice (Oryza sativa L.)

Rice plants are known to be silicon (Si) accumulators, hence farmers often use specific commercial chemical fertilizers to meet the nutrient needs of plants. Farmers commonly use fertilizers that are expensive and produce immediate effects, yet they contaminate the soil, water, and air. We should reduce the use of chemical fertilizers by combining a part of them with alternative organic and biological sources of Si, such as rice husk and Bacillus mucilaginosus (Si-solubilizing bacteria). Furthermore, it rationalizes chemical fertilizer consumption, reduces environmental pollution, and improves nutrient use efficiency to achieve rationalization of consumption with economic benefits in spending and rationalization of consumption of chemicals polluting the environment. In two successive growth seasons, 2021 and 2022, a field experiment was conducted to determine the effects of chemical, organic, and biological silicon fertilization in physiological studies of Egyptian Japonica green super rice. A randomized complete block design was used, with four replications, and the following treatments were used: T1, recommended dose of silica gel (SG; chemical Si); T2, recommended dose of rice husk (RH; organic Si); T3, recommended dose of Si-solubilizing bacteria (SSB; Bacillus mucilaginosus; biological Si); T4, ½ SG + ½ RH; T5, ½ SG + ½ SSB; T6, ½ RH + ½ SSB; T7, 1/3 SG + 1/3 RH + 1/3 SSB; T8, zero chemical, organic, and biological Si (control). The results showed that the application of silica gel as a chemical Si fertilizer, rice husk as an organic Si fertilizer, and Bacillus mucilaginosus as a Si-solubilizing bacteria or biological Si fertilizer source resulted in significantly higher yields of grain (10.71 and 10.53) t ha−1 and straw (12.66 and 12.37) t ha−1 in 2021 and 2022, respectively. Following that, silica gel, when combined with Si-solubilizing bacteria, led to increases in grain yield output of 10.32 and 10.39 t ha−1 and straw yield of 12.16 and 12.05 t ha−1 in 2021 and 2022, respectively. In addition, yield attributes, chlorophyll content in leaves, flag leaf area, flag leaf weight, chlorophyll in flag leaf, crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), and silicon uptake in grain and straw were determined as follows: The application of silica gel as a chemical Si fertilizer, rice husk as an organic Si fertilizer, and Bacillus mucilaginosus as a Si-solubilizing bacteria or biological Si fertilizer source had a substantial impact on all examined characteristics. According to the optimal treatment, one part of the three parts of Si fertilization utilized just chemical Si fertilizer and the other two parts organic and biological Si. So we can minimize chemical fertilizer use and reduce soil pollution. The findings of this study will be valuable for future research, such as the usage of alternative organic and biological sources of Si in rice.

Role of vermicompost and biochar in soil quality improvement by promoting Bupleurum falcatum L. nutrient absorption

AbstractBupleurum falcatum L. has gained attention due to its medicinal value in its root. B. falcatum was continuously cultivated and intensively chemically fertilized in order to attain a high yield, which reduced the soil quality and caused continuous cropping problems. Thus, there is a significant impact on S. baicalensis yield and quality. To solve this problem, soil with 0 or 3 continuous cropping years (0‐ and 3‐year soil) was fertilized with several organic materials, which are Bacillus subtilis, Bacillus mucilaginosus, humic acid fertilizer, biochar, and vermicompost. The experiment examined the effectiveness of B. falcatum's growth and nutrient uptake under various organic materials. It was shown that organic materials improved soil fertility and promoted the growth and nutrient uptake of B. falcatum. The combination of vermicompost and biochar had a better improvement effect. It increased soil nutrients by 23.8%–73.3% (0‐year soil) and 24.6%–71.1% (3‐year soil), respectively. In two types of soil, both microbial number and enzyme activity substantially increased. The B. falcatum shoot and root biomass with vermicompost was increased 74.8%–84.5% (without biochar) and 41.8%–71.1% (with biochar) in two types of soil. Vermicompost and biochar also significantly promoted the root development of B. falcatum. The root length increased by 13.3%–66.7%, the root diameter by 38.6%–84.8%, the root volume by 8.4%–61.3%, and the specific root length varied by −171.9% to 3.1% when compared with the control. The nutrient (N, P, and K) concentrations in shoots and roots changed from −3.9% to 67.2% and from 1.4% to 53.5%. All the findings demonstrated that long‐term continuous cropping caused cropping obstacles, deteriorated soil quality, and inhibited the B. falcatum growth. Applying organic fertilizers, such as vermicompost and biochar, can help to improve soil quality, increase soil nutrients, promote the growth and nutrient absorption of B. falcatum, and eliminate continuous cropping obstacles.

Bioleaching of available silicon from coal tailings using Bacillus mucilaginosus: a sustainable solution for soil improvement.

In China, a large amount of soil lack available silicon, which leads to a decrease in crop yield. Furthermore, the solid waste coal tailings contain abundant minerals that are rich in silicon, which have not been fully utilized. In this work, we used Bacillus mucilaginosus as the leaching agent to convert insoluble silicon in coal tailings into available silicon for crop. After single-factor experiments, the optimal leaching conditions with bacterial dosage, coal tailings weight, initial pH, leaching temperature, and shaking speed were obtained. Kinetic analysis showed that the controlling process of the leaching was a chemical reaction. The leaching process was characterized by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectrometer (FT-IR), and high-performance liquid chromatography (HPLC). The results showed that bioleaching is a feasible and efficient method to extract silicon from coal tailings, with a maximum leaching amount of 260 mg L-1 after 16 days, which occupied 93% of the total effective silicon. In conclusion, this work demonstrates that bioleaching technology can effectively solve the problem of the environmental utilization of coal tailings by converting them into a soil improver that can provide beneficial nutrients for crop growth.

PGPB and/or AM Fungi Consortia Affect Tomato Native Rhizosphere Microbiota.

Tomatoes are one of the most important crops worldwide and also play a central role in the human diet. Microbial consortia are microorganism associations, often employed as bioinoculants, that can interact with the native rhizosphere microbiota. The aim of this study was to evaluate the impact of a bacterial-based biostimulant (Pseudomonas fluorescens and Bacillus amyloliquefaciens) (PSBA) in combination, or not, with a commercial inoculum Micomix (Rhizoglomus irregulare, Funnelliformis mosseae, Funnelliformis caledonium, Bacillus licheniformis, Bacillus mucilaginosus) (MYC) on the native rhizosphere communities and on tomato production. The trial was carried out using Solanum lycopersicum in an open field as follows: control full NPK (CFD), control reduced NPK (CRD), MYC, PSBA, PSBA + MYC. Bacterial population in the different samples were characterized using a next generation sequencing approach. The bioinocula effect on the native rhizosphere microbiota resulted in significant variation both in alpha and beta diversity and in a specific signature associated with the presence of biostimulants, especially in the presence of co-inoculation (PSBA + MYC). In particular, the high initial biodiversity shifts in the community composition occurred and consisted in the increase in the abundance of genera correlated to the soil acidification and in an enhanced density of nitrogen-fixing microbes. The results also highlighted the well-known rhizosphere effect.

Synergistic Effect of Organic and Biofertilizers on Strawberry Cultivation

In the contemporary era, the excessive use of chemical fertilizers in areas where strawberries are intensively cultivated disrupts the balance of nature and reduces economic efficiency. Therefore, using organic and biofertilizers in sustainable agriculture can solve these problems. The effect of organic fertilizer and other treatments on the yield, quality, and plant growth of the Monterey strawberry variety was investigated. Solid farm manure and a liquid organic fertilizer of vegetable origin were used as basic fertilizers, while five different commercial fertilizers containing bacteria and mycorrhiza were used as complementary fertilizers. In addition, this study examined plant growth parameters, including root length, stem diameter, leaf area, yield per plant, fruit weight, pH in the fruit, SSC, acid, SSC-to-acid ratio, and plant nutrient content. The Biofarm+Botanica+Fontera microzone bacterial fertilizer (Azosprillium brasilense, Azotobacter vinelandii, Rhizobium trifollii, Pseudomonas fluorescens, Bacillus subtilis, Bacillus licheniformis, Azotobacter chroococcum, Bacillus amyloliquefaciens, and Bacillus mucilaginosus) treatment provided the best results; namely, it produced the highest total yield (250.17 g plant−1), largest fruits (18.13 g), highest SSC-to-acid ratio (18.05), and best nitrogen, phosphorus, potassium, calcium, and magnesium contents in the leaves. Similarly, the same treatment produced the longest root, thickest stem, and maximum leaf area. As a result of this study, it is recommended to use biofertilizers together with organic fertilizers to ensure high-quality fruit production.

Chemical mutation of Bacillus mucilaginosus genes to enhance the bioleaching of vanadium-bearing shale

The recovery and utilization of vanadium from vanadium-bearing shale are significant because vanadium is an important strategic metal. This study explored a cleaner metal extraction method to recover vanadium from vanadium-bearing shale using a novel strain of mutated Bacillus mucilaginosus (B.M) for an enhanced bioleaching process. The highly efficient bioleaching bacterium B.M-0.2 was obtained by chemical mutation using hydroxylamine hydrochloride. The optimal conditions for vanadium extraction by the mutagenized bacteria were 0.5 g/L ammonium nitrate, 5 g/L sucrose, pH 7.5, ore particle size of less than 0.074 mm accounting for 92.34% of the total, and pulp density of 10 g/L. Under these conditions, the vanadium leaching efficiency of B.M-0.2 was 8.16% higher than that of the original bacteria after a bioleaching period of 30 days. The Organic acid test results also showed that the mutant B.M-0.2 had notably high acid production. The genome of the mutant B.M-0.2 was sequenced via polymerase chain reaction, which revealed clear changes. Through KEGG pathway analysis, pathways related to the proteins that were differentially expressed between the two were also revealed. The results showed that the B.M mutated chemically using hydroxylamine hydrochloride has great potential to improve the recovery of vanadium from vanadium-bearing shale.