Silica Sol-Gel Microbead Encapsulation as a Novel Delivery Method for Symbiotic Microbes

Author(s):  
Luke Elissiry ◽  
Jingwen Sun ◽  
Ann M. Hirsch ◽  
Chong Liu

Synthetic fertilizer is responsible for the greatly increased crop yields that have enabled worldwide industrialization. However, the production and use of such fertilizers are environmentally unfriendly and unsustainable; synthetic fertilizers are produced via non-renewable resources and fertilizer runoff causes groundwater contamination and eutrophication. A promising alternative to synthetic fertilizer is bacterial inoculation. In this process, a symbiotic relationship is formed between a crop and bacteria species that can fix nitrogen, solubilize phosphorus, and stimulate plant hormone production. The bacteria carrier developed here aims to maintain bacteria viability while in storage, protect bacteria while encapsulated, and provide a sustained and controllable bacterial release. This novel bacterial delivery method utilizes inorganic nanomaterials, silica microbeads, to encapsulate symbiotic bacteria. These microbeads, which were produced with aqueous, non-toxic precursors, are sprayed directly onto crop seeds and solidify on the seeds as a resilient silica matrix. The bacterial release from the carrier was found by submerging coated seeds in solution to simulate degradation in soil environments, measuring the number of bacteria released by the plate count technique, and comparing the carrier to seeds coated only in bacteria. The carrier’s effectiveness to enhance plant growth was determined through greenhouse plant assays with alfalfa (<i>Medicago sativa</i>) plants and the nitrogen-fixing <i>Sinorhizobium meliloti</i> Rm1021 strain. When compared to bacteria-only inoculation, the silica microbead carrier exhibited significantly (P < 0.05) increased holding capacity of viable bacteria and increased plant growth by a similar amount, demonstrating the capability of inorganic nanomaterials for microbial delivery. The carrier presented in this work has potential applications for commercial agriculture and presents an opportunity to further pursue more sustainable agricultural practices.

2020 ◽  
Author(s):  
Luke Elissiry ◽  
Jingwen Sun ◽  
Ann M. Hirsch ◽  
Chong Liu

Synthetic fertilizer is responsible for the greatly increased crop yields that have enabled worldwide industrialization. However, the production and use of such fertilizers are environmentally unfriendly and unsustainable; synthetic fertilizers are produced via non-renewable resources and fertilizer runoff causes groundwater contamination and eutrophication. A promising alternative to synthetic fertilizer is bacterial inoculation. In this process, a symbiotic relationship is formed between a crop and bacteria species that can fix nitrogen, solubilize phosphorus, and stimulate plant hormone production. The bacteria carrier developed here aims to maintain bacteria viability while in storage, protect bacteria while encapsulated, and provide a sustained and controllable bacterial release. This novel bacterial delivery method utilizes inorganic nanomaterials, silica microbeads, to encapsulate symbiotic bacteria. These microbeads, which were produced with aqueous, non-toxic precursors, are sprayed directly onto crop seeds and solidify on the seeds as a resilient silica matrix. The bacterial release from the carrier was found by submerging coated seeds in solution to simulate degradation in soil environments, measuring the number of bacteria released by the plate count technique, and comparing the carrier to seeds coated only in bacteria. The carrier’s effectiveness to enhance plant growth was determined through greenhouse plant assays with alfalfa (<i>Medicago sativa</i>) plants and the nitrogen-fixing <i>Sinorhizobium meliloti</i> Rm1021 strain. When compared to bacteria-only inoculation, the silica microbead carrier exhibited significantly (P < 0.05) increased holding capacity of viable bacteria and increased plant growth by a similar amount, demonstrating the capability of inorganic nanomaterials for microbial delivery. The carrier presented in this work has potential applications for commercial agriculture and presents an opportunity to further pursue more sustainable agricultural practices.


2004 ◽  
Vol 5 (1) ◽  
pp. 43
Author(s):  
Any Mercedes Lucero Mafla ◽  
Luis Alberto Peña Villamil ◽  
Tito Bacca Ibarra

<p>Actualmente, en los municipios del departamento de Nariño (Colombia), en los cultivos de trigo y papa que son los principales sistemas de producción, se presentan altas infestaciones de poblaciones de chisas encontrándose hasta 350 larvas/m2, representando un factor limitante para la producción de los cultivos. Una alternativa promisoria para el manejo de esta plaga es la utilización de métodos biológicos que incluyen el uso de hongos entomopatógenos. El objetivo del presente trabajo fue el de evaluar el efecto de <em>Beauveria bassiana, Metarhizium anisopliae </em>sobre larvas de <em>Ancognatha scarabaeoides </em>en laboratorio e invernadero. Los aislamientos de hongos se obtuvieron de larvas infectadas en los municipios de Yacuanquer y Ospina. En el laboratorio, se seleccionaron 5 de 9 aislamientos de hongos: Mt1, Bb cosmo, Mt2, Bb4 y Bb10 que presentaron mortalidades superiores al 50%, éstas se evaluaron a concentraciones de 1x105 a 1x1010 esporas/ml. El porcentaje acumulado de mortalidad a los 18 días después de la inoculación fueron: del 100% para Bb cosmo, Mt1 y Mt2 en la concentración de 1x1010 esporas/ml y del 90% para Bb4 y Bb10 en la concentración de 1x109 esporas/ml, presentando concentraciones letales 90(CL90) de 1.1x1010, 7.3x109, 2.2x1010, 3.9x1010 y 4.3x1010 esporas/ml respectivamente. En invernadero se evaluaron los mismos microorganismos con sus respectivas concentraciones letales 50(CL50) y 90(CL90), encontrándose porcentajes de mortalidad del 76.00%, 67.50%, 63.50%, 59.00% y 53.50% para Mt1, Bb cosmo, Mt2, Bb4 y Bb10. Estos resultados indican la posibilidad de incluir estos biocontroladores nativos en el manejo integrado de las chisas en Nariño.</p><p> </p><p><strong>Evaluation of the biocontrol activity of <em>Beauveria bassiana, Metarhizium anisopliae</em>, on larvae of <em>Ancognatha scarabaeoides </em>(Coleoptera: Scarabaeidae).</strong></p><p>High grub populations of coleopteran, frequently attack crops of wheat and potato in the Department of Nariño, Colombia. Reports indicate that infestations levels reach more than 350 larvae/ m2, which severely reduce crop yields. Use of biological control measurements as fungal entomopathogens seems to be a promising alternative for management of this pest. The present work aimed to evaluate the effect of <em>Beauveria bassiana </em>and <em>Metarhizium anisopliae </em>on larvae of <em>Ancognatha scarabaeoides </em>both in laboratory and greenhouse conditions. Isolates of entomopathogen fungus were obtained from infected larvae in the municipalities of Yacuanquer and Ospina. A sample of 5 isolates, which previously had shown to cause mortality rates higher than 50%, was selected in the laboratory: Mt1, Bb cosmo, Mt2, Bb4 and Bb10. Isolates concentrations from 1x105 to 1x1010 spores/ml were tested. The cumulative mortality percentage (at 18 days after the inoculation) ranged from 100% with Bb cosmo, Mt1 and Mt2 at concentrations of 1x1010 spores/ml to 90% with Bb4 and Bb10 at concentrations of 1x109 spores/ml. Lethal doses 90 (LD90) of 1.1x1010, 7.3x109, 2.2x1010, 3.9x1010 and 4.3x1010 spores/ml were calculated for each isolate, respectively. An evaluation of the biocontrol activity of the isolates was carried out under greenhouse conditions. Mortality percentages obtained reached 76%, 67.5%, 63.5%, 59% and 53.5% for Mt1, Bb cosmo, Mt2, Bb4 and Bb10, respectively. These results suggest that the use of native biocontrolers is a promising alternative to be included in the integrated management for white grubs in Nariño.</p>


Cellulose ◽  
2019 ◽  
Vol 26 (18) ◽  
pp. 9403-9412 ◽  
Author(s):  
Maria Gunnarsson ◽  
Merima Hasani ◽  
Diana Bernin

Abstract Cellulose is the most important biopolymer on earth and, when derived from e.g. wood, a promising alternative to for example cotton, which exhibits a large environmental burden. The replacement depends, however, on an efficient dissolution process of cellulose. Cold aqueous alkali systems are attractive but these solvents have peculiarities, which might be overcome by understanding the acting mechanisms. Proposed dissolution mechanisms are for example the breakage of hydrophobic interactions and partly deprotonation of the cellulose hydroxyl groups. Here, we performed a mechanistic study using equimolar aqueous solutions of LiOH, NaOH and KOH to elucidate the dissolution process of microcrystalline cellulose (MCC). The pH was the highest for KOH(aq) followed by NaOH(aq) and LiOH(aq). We used a combination of conventional and advanced solution-state NMR methods to monitor the dissolution process of MCC by solely increasing the temperature from − 10 to 5 °C. KOH(aq) dissolved roughly 25% of the maximum amount of MCC while NaOH(aq) and LiOH(aq) dissolved up to 70%. Water motions on nanoscale timescales present in non-frozen water, remained unaffected on the addition of MCC. Magnetisation transfer (MT) NMR experiments monitored the semi-rigid MCC as a function of temperature. Interestingly, although NaOH(aq) and LiOH(aq) were able to dissolve a similar amount at 5 °C, MT spectra revealed differences with increasing temperature, suggesting a difference in the swollen state of MCC in LiOH(aq) already at − 10 °C. Furthermore, MT NMR shows a great potential to study the water exchange dynamics with the swollen and semi-rigid MCC fraction in these systems, which might give valuable insights into the dissolution mechanism in cold alkali.


Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 899 ◽  
Author(s):  
D. P. C. Stewart ◽  
K. C. Cameron ◽  
I. S. Cornforth ◽  
J. R. Sedcole

A 2-year field trial determined the influence of applying spent mushroom substrate (SMS) on soil physical properties and the growth of 4 consecutive vegetable crops (sweetcorn, cabbage, potato, cabbage). Treatments comprised 0, 20, 40, and 80 t/ha of moist SMS, both with and without inorganic fertiliser, applied to each crop, giving a range of SMS rates up to 320 t/ha. SMS improved the environment for plant root growth by decreasing soil bulk density (by 0· 05-0·25 g/cm 3 at 100 mm depth), increasing aggregate stability (by 13-16%), reducing clod and surface crust formation (by 16-31 and 18-94%, respectively), increasing the infiltration rate (by 130-207 mm/h), increasing the water content of the soil (by 0-7% w/w), and reducing diurnal temperature changes. Some of these changes were not evident until repeated applications of 80 t/ha SMS had been made. Soil physical properties were related to crop yield, and soil physical properties’ principal components were related to crop principal components using regression analysis (r2 of 0·20-0·60 and 0·16-0·54, respectively). The soil physical properties that had the most influence on plant growth were specific to each crop and included bulk density, water content, surface crust cover, infiltration rate, and aggregate size distribution. Soil physical properties had a large influence on the potato yield irrespective of fertiliser use and on both cabbage crop yields when fertiliser was not used, but not on the sweetcorn yield (the first crop to be grown). The effect of changing soil physical properties on plant growth was most apparent when fertiliser was not used. This was because the improved physical properties increased plant yield (at least in part) because of increased plant nutrient uptake.


2019 ◽  
Vol 64 (2) ◽  
pp. 153-161 ◽  
Author(s):  
László Nagy-Győr ◽  
Emese Farkas ◽  
Mihai Lăcătuș ◽  
Gergő Tóth ◽  
Dániel Incze ◽  
...  

In this study, an efficient and generally applicable 2nd generation sol – gel entrapment method was developed for immobilization of yeastcells. Cells of Lodderomyces elongisporus, Candida norvegica, Debaryomyces fabryi, Pichia carsonii strains in admixture with hollow silica microspheres support were immobilized in sol – gel matrix obtained from polycondensation of tetraethoxysilane. As biocatalysts in theselective acyloin condensation of benzaldehyde catalyzed by pyruvate decarboxylase of the yeast, the novel immobilized whole-cell preparations were compared to other states of the cells such as freshly harvested wet cell paste, lyophilized cells and sol – gel entrapped preparations without hollow silica microspheres support. Reusability and storability studies designated this novel 2nd generation sol – gel method as a promising alternative for solid formulation of whole-cells bypassing expensive and difficult downstream steps while providing easy-to-handle and stable biocatalysts with long-term preservation of the biocatalytic activity.


Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 192 ◽  
Author(s):  
Domenico Ronga ◽  
Elisa Biazzi ◽  
Katia Parati ◽  
Domenico Carminati ◽  
Elio Carminati ◽  
...  

Microalgae are attracting the interest of agrochemical industries and farmers, due to their biostimulant and biofertiliser properties. Microalgal biostimulants (MBS) and biofertilisers (MBF) might be used in crop production to increase agricultural sustainability. Biostimulants are products derived from organic material that, applied in small quantities, are able to stimulate the growth and development of several crops under both optimal and stressful conditions. Biofertilisers are products containing living microorganisms or natural substances that are able to improve chemical and biological soil properties, stimulating plant growth, and restoring soil fertility. This review is aimed at reporting developments in the processing of MBS and MBF, summarising the biologically-active compounds, and examining the researches supporting the use of MBS and MBF for managing productivity and abiotic stresses in crop productions. Microalgae are used in agriculture in different applications, such as amendment, foliar application, and seed priming. MBS and MBF might be applied as an alternative technique, or used in conjunction with synthetic fertilisers, crop protection products and plant growth regulators, generating multiple benefits, such as enhanced rooting, higher crop yields and quality and tolerance to drought and salt. Worldwide, MBS and MBF remain largely unexploited, such that this study highlights some of the current researches and future development priorities.


2000 ◽  
Vol 80 (1) ◽  
pp. 33-41 ◽  
Author(s):  
G.C. Topp ◽  
B. Dow ◽  
M. Edwards ◽  
E. G. Gregorich ◽  
W. E. Curnoe ◽  
...  

Deleterious soil structural conditions, as from compaction, can reduce plant growth and yields by reducing aeration and oxygen in the rooting environment. Using a double-membrane oxygen cathode in each of four corn plots, we measured soil oxygen concentrations in duplicate at depths of 5, 10, 20 and 30 cm during the growing season. In addition, temperature, water content and bulk density determinations allowed the monitoring of O2 concentration trends under no-till and conventional-till corn management. Carbon dioxide flux from the soil surface was measured weekly. Temporal patterns of O2 levels fluctuated in response to rainfall at all depths but much less so at 30-cm depth. At 30 cm the O2 concentration remained inadequate for optimum plant growth (<0.01 kg m−3) for over 2 mo after planting under no-till with poorly timed trafficking. Under conventional till and appropriately timed trafficking adequate aeration occurred more than a month earlier than under no-till. The CO2 output was generally lower by 10 to 30% in no-till than that in conventional till, indicating measurably lower levels of biological activity. The relative magnitudes of mid-season O2 concentrations and CO2 flux densities showed the same pattern as the crop yields for all tillage treatments. More analyses of seasonal O2 consumption patterns are required to determine if lack of O2 is a causal factor for the reduced crop yield. Key words: TDR, aeration, oxygen measurement, carbon dioxide, tillage, root zone


2013 ◽  
Vol 789 ◽  
pp. 28-32 ◽  
Author(s):  
Bambang Priyono ◽  
Akhmad Herman Yuwono ◽  
B. Munir ◽  
A. Rahman ◽  
A. Maulana ◽  
...  

Dye-sensitized solar cell (DSSC) is one of the very promising alternative renewable energy sources to anticipate the diminishing in the fossil fuel reserves in the next few decades and to make use of the abundance of intensive sunlight energy in tropical countries like Indonesia. TiO2nanoparticles have been used as the photo electrode in DSSC because of its high surface area and allow the adsorption of a large number of dye molecules. In the present study, TiO2aerogel have been synthesized via sol-gel process with water to inorganic precursor ratio (Rw) of 2.00, followed with subsequent drying by CO2supercritical extraction (SCE). As comparison, the TiO2xerogel was also prepared by conventional drying and annealing. Both types of gels were subjected to conventional and multi-step annealing. The resulting nanoparticles in aerogel and xerogel have a band-gap energy of 3.10 and 3.04 eV, respectively. The open circuit voltage (Voc) measurement reveals that the DSSC fabricated with aerogel provided a higher voltage (21,40 mV) than xerogel (1,10 mV).


The development and marketing of novel technology by the chemical industry has been a fundamental ingredient in the improvement of crop yields. Further advances will result from the continuing development of more effective pesticides. Improved application technology and better diagnosis of precise crop requirements will also lead to the more efficient usage of existing and future products. New approaches to crop improvement based on chemical plant-growth regulators and genetic engineering of plants represent major technological opportunities for the future. Realization of these opportunities demands a substantially increased investment in basic plant research, a requirement already recognized within the chemical industry.


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