Scale-up from shake flasks to pilot-scale production of the plant growth-promoting bacterium Azospirillum brasilense for preparing a liquid inoculant formulation

For pilot-scale production of chito-oligosaccharides, it must be cost-effective to prepare designable recombinant chitosanase. Herein, an efficient method for preparing recombinant Bacillus chitosanase from Escherichia coli by elimination of undesirable substances as a precipitate is proposed. After an optimized culture with IPTG (Isopropyl β-d-1-thiogalactopyranoside) induction, the harvested cells were resuspended, disrupted by sonication, divided by selective precipitation, and stored using the same solution conditions. Several factors involved in these procedures, including ion types, ionic concentration, pH, and bacterial cell density, were examined. The optimal conditions were inferred to be pH = 4.5, 300 mM sodium dihydrogen phosphate, and cell density below 1011 cells/mL. Finally, recombinant chitosanase was purified to >70% homogeneity with an activity recovery and enzyme yield of 90% and 106 mg/L, respectively. When 10 L of 5% chitosan was hydrolyzed with 2500 units of chitosanase at ambient temperature for 72 h, hydrolyzed products having molar masses of 833 ± 222 g/mol with multiple degrees of polymerization (chito-dimer to tetramer) were obtained. This work provided an economical and eco-friendly preparation of recombinant chitosanase to scale up the hydrolysis of chitosan towards tailored oligosaccharides in the near future.

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Ultrastructure of interaction in alginate beads between the microalgaChlorella vulgariswith its natural associative bacteriumPhyllobacterium myrsinacearumand with the plant growth-promoting bacteriumAzospirillum brasilense

Canadian Journal of Microbiology ◽

10.1139/w00-115 ◽

2001 ◽

Vol 47 (1) ◽

pp. 1-8 ◽

Cited By ~ 37

Author(s):

Vladimir K Lebsky ◽

Luz E Gonzalez-Bashan ◽

Yoav Bashan

Keyword(s):

Wastewater Treatment ◽

Plant Growth ◽

Azospirillum Brasilense ◽

Bacterial Species ◽

Alginate Beads ◽

Transmission Electron ◽

Associative Bacteria ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Treatment Water

Chlorella vulgaris, a microalga often used in wastewater treatment, was coimmobilized and coincubated either with the plant growth-promoting bacterium Azospirillum brasilense, or with its natural associative bacterium Phyllobacterium myrsinacearum, in alginate beads designed for advanced wastewater treatment. Interactions between the microalga and each of the bacterial species were followed using transmission electron microscopy for 10 days. Initially, most of the small cavities within the beads were colonized by microcolonies of only one microorganism, regardless of the bacterial species cocultured with the microalga. Subsequently, the bacterial and microalgal microcolonies merged to form large, mixed colonies within the cavities. At this stage, the effect of bacterial association with the microalga differed depending on the bacterium present. Though the microalga entered a senescence phase in the presence of P. myrsinacearum, it remained in a growth phase in the presence of A. brasilense. This study suggests that there are commensal interactions between the microalga and the two plant associative bacteria, and that with time the bacterial species determined whether the outcome for the microalga is senescence or continuous multiplication.Key words: Azospirillum, Chlorella, Phyllobacterium, wastewater treatment, water bioremediation.

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Protection of Tomato Seedlings against Infection by Pseudomonas syringae pv. Tomato by Using the Plant Growth-Promoting Bacterium Azospirillum brasilense

Applied and Environmental Microbiology ◽

10.1128/aem.68.6.2637-2643.2002 ◽

2002 ◽

Vol 68 (6) ◽

pp. 2637-2643 ◽

Cited By ~ 72

Author(s):

Yoav Bashan ◽

Luz E. de-Bashan

Keyword(s):

Plant Growth ◽

Pseudomonas Syringae ◽

Azospirillum Brasilense ◽

Dry Weight ◽

Tomato Plants ◽

Bacterial Speck ◽

Plant Growth Promoting ◽

Bacterial Speck Disease ◽

Growth Promoting ◽

Mist Chamber

ABSTRACT Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (107 versus 105 CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (107 versus 106 CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (105 to 106 CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>108 CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato.

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Promoter-trap identification of wheat seed extract-induced genes in the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp245

Microbiology ◽

10.1099/mic.0.2007/009381-0 ◽

2007 ◽

Vol 153 (10) ◽

pp. 3608-3622 ◽

Cited By ~ 58

Author(s):

Joël F. Pothier ◽

Florence Wisniewski-Dyé ◽

Michèle Weiss-Gayet ◽

Yvan Moënne-Loccoz ◽

Claire Prigent-Combaret

Keyword(s):

Plant Growth ◽

Azospirillum Brasilense ◽

Seed Extract ◽

Wheat Seed ◽

Promoter Trap ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Induced Genes

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Inoculation with the Plant-Growth-Promoting Rhizobacterium Azospirillum brasilense Causes Little Disturbance in the Rhizosphere and Rhizoplane of Maize (Zea mays)

Microbial Ecology ◽

10.1007/s00248-004-0148-x ◽

2005 ◽

Vol 50 (2) ◽

pp. 277-288 ◽

Cited By ~ 52

Author(s):

Yoav Herschkovitz ◽

Anat Lerner ◽

Yaacov Davidov ◽

Michael Rothballer ◽

Anton Hartmann ◽

...

Keyword(s):

Zea Mays ◽

Plant Growth ◽

Azospirillum Brasilense ◽

Plant Growth Promoting ◽

Growth Promoting

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Effect of Azospirillum brasilense and mycorrhizal soil fungi on topinambur grown in a greenhouse

Journal of Applied Biotechnology & Bioengineering ◽

10.15406/jabb.2021.08.00261 ◽

2021 ◽

Vol 8 (4) ◽

pp. 104-110

Author(s):

Di Barbaro Gabriela ◽

Andrada Horacio ◽

Batallan Morales Silvana ◽

Espeche Acosta Eliana ◽

Rizo Melisa ◽

...

Keyword(s):

Plant Growth ◽

Mycorrhizal Fungi ◽

Azospirillum Brasilense ◽

Soil Fungi ◽

Jerusalem Artichoke ◽

Promoting Effect ◽

Greenhouse Production ◽

Plant Growth Promoting ◽

Growth Promoting ◽

The Moment

To determine the effect of Azospirillum brasilense and soil mycorrhizal fungi on the nutrition of the Jerusalem artichoke crop (Helianthus tuberosus L.), evaluations of agronomic parameters and the health status of the plants were carried out, under greenhouse conditions. The tests were carried out, at the moment of the implantation of the culture: the tubers were inoculated with A. brasilense and with native mycorrhizal fungi, generating four treatments including the control and the co-inoculation of the consortium of the microorganisms under study (T0: control or control without inoculation; T1: inoculation with native A. brasilense; T2: inoculation with native mycorrhizal fungi and T3: joint inoculation with A. brasilense and native mycorrhizal fungi. The results indicate that co-inoculation with A. brasilense and with native mycorrhizal fungi increased plant growth in height, leaf area, biomass, dry matter, and yields significantly in greenhouse production. It was determined that the application of the selected microorganisms has a plant growth-promoting effect, increasing the productivity of cultivated topinambur in the greenhouse

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Using two plant growth promoting bacteria to sustainably reduce the drought-induced loss in Triticum aestivum yield

Notulae Scientia Biologicae ◽

10.15835/nsb12210580 ◽

2020 ◽

Vol 12 (2) ◽

pp. 433-446

Author(s):

El-Anwar OSMAN ◽

Wedad A. KASIM ◽

Nabil A. OMAR ◽

Samar E. SALAMA

Keyword(s):

Amino Acids ◽

Drought Stress ◽

Plant Growth ◽

Free Amino Acids ◽

Free Amino ◽

Azospirillum Brasilense ◽

Stenotrophomonas Maltophilia ◽

Plant Growth Promoting ◽

Total Free Amino Acids ◽

Growth Promoting

In a greenhouse experiment, the inoculated and uninoculated grains with Azospirillum brasilense NO40 or Stenotrophomonas maltophilia were sown in unsterilized sandy soil and watered normally till the 8th day. Thereafter, the drought stress was initiated by watering pots once every 10 days while the unstressed pots were irrigated normally once every 5 days. Samples of spikes and dry grains were collected after 120 days from sowing. The results indicated that the inoculated-drought-stressed plants maintained significantly higher values of all of the measured yield parameters, where the yielded grains had higher amounts of the direct reducing sugars, sucrose, starch; lower contents of total soluble proteins and the total free amino acids, and altered protein patterns compared to those of the uninoculated-drought-stressed plants. SDS-PAGE of the yielded grains showed that drought led to the appearance of some newly synthesized stress protein bands and disappearance of others. Inoculation with PGPB resulted in the re-appearance of some of the disappearing bands and the synthesis of new others. Meanwhile, wheat inoculation under normal conditions resulted in significantly promoted grain yields with higher contents of carbohydrates, total soluble proteins and total free amino acids than that of the uninoculated control. It has been proved that treating wheat plants with the PEG-tolerant Azospirillum brasilense NO40 or Stenotrophomonas maltophilia that were compatible with the systems into which they were introduced and possess multiple plant growth promoting traits, can be an efficient strategy to enhance wheat growth and productivity, not only under normal conditions, but also under drought stress.

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Compatibility of Azospirillum brasilense with Pesticides Used for Treatment of Maize Seeds

International Journal of Microbiology ◽

10.1155/2020/8833879 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Mariana S. Santos ◽

Artur B. L. Rondina ◽

Marco A. Nogueira ◽

Mariangela Hungria

Keyword(s):

Plant Growth ◽

Root Hair ◽

Azospirillum Brasilense ◽

Plant Protection ◽

Plant Growth Promoting Bacteria ◽

Root Volume ◽

Maize Seeds ◽

Plant Growth Promoting ◽

Growth Promoting

Seed treatment with chemical pesticides is commonly used as an initial plant protection procedure against pests and diseases. However, the use of such chemicals may impair the survival and performance of beneficial microorganisms introduced via inoculants, such as the plant growth-promoting bacterium Azospirillum brasilense. We assessed the compatibility between the most common pesticide used in Brazil for the treatment of maize seeds, composed of two fungicides, and one insecticide, with the commercial strains Ab-V5 and Ab-V6 of A. brasilense, and evaluated the impacts on initial plant development. The toxicity of the pesticide to A. brasilense was confirmed, with an increase in cell mortality after only 24 hours of exposure in vitro. Seed germination and seedling growth were not affected neither by the A. brasilense nor by the pesticide. However, under greenhouse conditions, the pesticide affected root volume and dry weight and root-hair incidence, but the toxicity was alleviated by the inoculation with A. brasilense for the root volume and root-hair incidence parameters. In maize seeds inoculated with A. brasilense, the pesticide negatively affected the number of branches, root-hair incidence, and root-hair length. Therefore, new inoculant formulations with cell protectors and the development of compatible pesticides should be searched to guarantee the benefits of inoculation with plant growth-promoting bacteria.

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