Preservation of Azotobacter chroococcum vegetative cells in dry polymers

Rojas‐Tapias, Daniel F.; Sierra, Oriana Ortega; Botía, Diego Rivera; Bonilla, Ruth

doi:10.11144/javeriana.sc20-2.pacv

Cited by 8 publications

(7 citation statements)

References 17 publications

(18 reference statements)

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“…The protectant effect of polymers was observed because the energy of activation increased when compared with the control (PBS), meaning that it takes more energy and time for cells to start degrading. The experimental values of the activation energy in our study (with a maximum value of 13.2 kcal/mol) were inferior to those described by other authors for Azotobacter (22.07 kcal/mol) and Bacillus spores (19.7 kcal/mol) when they were evaluating the effect of carrageenan, alginate and acacia gum over cell viability (Rojas-Tapias et al, 2015;Sorokulova et al 2008), but is necessary to highlight that, Azospirillum is much more sensitive to temperature than those microorganisms, and Bacillus spores are more resistant to any kind of stress. According to Dell et al (2007) and Huey and Kingsolver (2011), the use of the Arrhenius model is well accepted for biological processes, fitting in about 80 to 90% the behavior of thermal sensitivity among plants, microbes and animals.…”

Section: Screening Under Stress Conditionscontrasting

confidence: 99%

“…The viscosity and water holding capacity of these hydrophilic polymers reduced the drying rate and helped to protect cells from environmental stresses. Similar results were obtained with carrageenan on Azotobacter chroococcum (Rojas-Tapias et al, 2015), and alginate with Rhizobium and Bradyrhizobium strains (Tittabutr et al, 2007;Rivera et al, 2014). It is important to establish that these two polymers are used in other type of formulations like microencapsulation, which have been proved to maintain cell viability of nitrogen fixing bacteria for over fourteen years (Bashan and Gonzalez, 1999).…”

Section: Screening Under Stress Conditionsmentioning

confidence: 62%

“…Data of bacterial death during time helped to determine the apparent rate constants of degradation for each polymer, and the energy of activation was determined in a plot where the log of the rate is linearly related to the inverse of absolute temperature. In terms of viability, the energy of activation is the energy barrier needed to overcome cell degradation (Rojas-Tapias et al, 2015). The protectant effect of polymers was observed because the energy of activation increased when compared with the control (PBS), meaning that it takes more energy and time for cells to start degrading.…”

Section: Screening Under Stress Conditionsmentioning

confidence: 99%

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Polymers selection for a liquid inoculant of Azospirillum brasilense based on the Arrhenius thermodynamic model

and¹,

Rebeca²

2015

Afr. J. Biotechnol.

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Plant growth promoting bacteria (PGPB) enhances the growth of their hosts and can protect them from biotic and abiotic stresses. Bacterial inoculants contain one or more of these beneficial strains in a carrier material, which must be able to maintain the viability of the cells during the time of storage, and also guarantee the biological activity of the strains once applied in the soil. These inoculants can be solid, liquid, gel or oil-based, depending on the characteristics of the strains and the shelf life expected by the producers. In this study, we used a method of accelerated degradation to select a polymer and a concentration to maintain cell stability of a liquid inoculant based on the strain C16 Azospirillum brasilense. A screening at 45°C was made to compare the protectant effect of five polymers on the viability of the strain (p/v): carrageenan (1.5%), sodium alginate (1%), trehalose (10 mM), polyvinylpyrrolidone (2%), glycerol (10 mM) and phosphate saline buffer as control. Carrageenan and sodium alginate showed significant differences in cell viability over the use of other polymers (P < 0.05). We evaluated cell viability with these two polymers at three concentrations and three different temperatures (4, 28 and 45°C) for 60 days and determined the bacterial degradation rates. Based on the Arrhenius thermodynamic model, we calculated the time required to reduce cell concentration in three log units, and observed that the protectant activity of each polymer and each concentration depends on the temperature of storage. Cell viability was best preserved in all treatments at 4°C. In general, alginate prolonged cell viability at 28°C, and carrageenan at 45°C. Alginate at 1% and carrageenan at 0.75% showed a stable behavior (superior to the control) in the three evaluated temperatures, so we conclude that they can be used for a formulation of a liquid inoculant based on the strain C16 of A. brasilense.

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Section: Screening Under Stress Conditionscontrasting

confidence: 99%

Section: Screening Under Stress Conditionsmentioning

confidence: 62%

Section: Screening Under Stress Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Polymers selection for a liquid inoculant of Azospirillum brasilense based on the Arrhenius thermodynamic model

and¹,

Rebeca²

2015

Afr. J. Biotechnol.

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“…The protection capabilities of dry biopolymers were illustrated by the accelerated aging in alginate, POLYOX, carrageenan, and acacia gum (Rojas-Tapias et al 2013, 2015. They reported storage enhancement of 1.8-5.5 (Table 2).…”

Section: Examples Of Preservation Of Microorganisms In Natural Biopolmentioning

confidence: 95%

Biopolymers for sample collection, protection, and preservation

Sorokulova

Olsen

Vodyanoy

2015

Appl Microbiol Biotechnol

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One of the principal challenges in the collection of biological samples from air, water, and soil matrices is that the target agents are not stable enough to be transferred from the collection point to the laboratory of choice without experiencing significant degradation and loss of viability. At present, there is no method to transport biological samples over considerable distances safely, efficiently, and cost-effectively without the use of ice or refrigeration. Current techniques of protection and preservation of biological materials have serious drawbacks. Many known techniques of preservation cause structural damages, so that biological materials lose their structural integrity and viability. We review applications of a novel bacterial preservation process, which is nontoxic and water soluble and allows for the storage of samples without refrigeration. The method is capable of protecting the biological sample from the effects of environment for extended periods of time and then allows for the easy release of these collected biological materials from the protective medium without structural or DNA damage. Strategies for sample collection, preservation, and shipment of bacterial, viral samples are described. The water-soluble polymer is used to immobilize the biological material by replacing the water molecules within the sample with molecules of the biopolymer. The cured polymer results in a solid protective film that is stable to many organic solvents, but quickly removed by the application of the water-based solution. The process of immobilization does not require the use of any additives, accelerators, or plastifiers and does not involve high temperature or radiation to promote polymerization.

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“…Tapias et al 2013;Rojas-Tapias et al 2015), que provienen del metabolismo de diversos microorganismos, paredes celulares de las algas marinas y resina de árboles. Existen varios requisitos para que estos polímeros sean componentes de inoculantes, tales como no ser tóxicos, proteger a los microorganismos inoculados de competidores de suelo y de factores ambientales y ser lentamente…”

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Caracterización de la colonización y promoción del crecimiento vegetal por <i>Burkholderia tropica</i> en gramíneas

Bernabeu¹

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Objetivo general Desarrollar metodologías conducentes a la aplicación agronómica de bacterias diazótrofas endófitas promotoras del crecimiento vegetal como una nueva alternativa de inoculación en gramíneas, particularmente cereales, que contribuya a la sustentabilidad económica y ambiental de estos cultivos, procurando un mejor aprovechamiento de los recursos naturales del suelo y del ambiente. Objetivos específicos 1. Evaluar algunas de las habilidades de B. tropica MTo-293 como colonizadora competente y como promotora del crecimiento vegetal: a- la formación biofilm y la producción de enzimas líticas b- la solubilización de compuestos insolubles de fósforo. 2. Caracterizar el proceso de colonización de B. tropica MTo-293 en plantas de trigo y sorgo después de inocular semillas de ambas gramíneas, como primer requisito para poder expresar los posibles efectos benéficos. 3. Evaluar aspectos prácticos fundamentales para el posible uso de B. tropica MTo-293 como inoculante: a- viabilidad bacteriana en formulaciones líquidas y sobre la superficie de las semillas; b- compatibilidad con agroquímicos. 4. Evaluar el efecto promotor de B. tropica MTo-293 en ambos cereales en ensayos a campo. 5. Realizar la búsqueda de genes de B. tropica MTo-293 relacionados con la rizocompetencia y la promoción del crecimiento vegetal.

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Preservation of Azotobacter chroococcum vegetative cells in dry polymers

Cited by 8 publications

References 17 publications

Polymers selection for a liquid inoculant of Azospirillum brasilense based on the Arrhenius thermodynamic model

Polymers selection for a liquid inoculant of Azospirillum brasilense based on the Arrhenius thermodynamic model

Biopolymers for sample collection, protection, and preservation

Caracterización de la colonización y promoción del crecimiento vegetal por <i>Burkholderia tropica</i> en gramíneas

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