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Viana JL, da Silva JS, de Mattos GC, Pinto MCC, Dutra LDS, Carvalho LLDA, Pinto JCCDS, Pinheiro VCS, Roque RA. Microencapsulation of Bacillus thuringiensis strains for the control of Aedes aegypti. Exp Parasitol 2023; 255:108654. [PMID: 37956783 DOI: 10.1016/j.exppara.2023.108654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/15/2023]
Abstract
In this study, we investigated the microencapsulation of two strains of the entomopathogenic bacteria Bacillus thuringiensis (B. thuringiensis) (BtMA-750 and BtMA-1114), which are biopesticides of high toxicity for the mosquito vector Aedes aegypti. The encapsulation of different concentrations of microorganisms in starch microparticles was evaluated, and the inverse suspension polymerization technique was explored. It was possible to observe that the higher amounts of the biopesticide caused a slight decrease in the diameter of the particles; however, even when encapsulated, the biopesticide still presents an average diameter that is able to be consumed by the larvae of Aedes aegypti. Furthermore, it was noticed that the presence of both of the B. thuringiensis strains did not affect the thermal stability of the particles. The microencapsulated bacterial strains presented a high number of viable spores and preserved the expression of proteins with molecular masses corresponding to the insecticidal toxins Cry and Cyt, indicating that the encapsulation process was conducted satisfactorily. Finally, the encapsulated strains were tested against Ae. aegypti larvae and maintained 100% larval mortality even after 35 days. Therefore, microencapsulation of B. thuringiensis not only guarantees the bacterial activity, but also prolongs the action of the biopesticide. Collectively, such findings highlight the great potential of the new biopesticides, which may help to reduce the population indices of the mosquito vector Ae. aegypti via a sustainable and environment-friendly route.
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Affiliation(s)
- Juliete L Viana
- Universidade do Estado do Amazonas - UEA, Programa de Pós-graduação em Biodiversidade e Biotecnologia da Rede BIONORTE - PPG BIONORTE, Av. Carvalho Leal, 1777, Ed. Anexo, 4° andar, Cachoeirinha, Manaus, CEP 69065001, AM, Brazil.
| | - Joelma S da Silva
- Curso Ciências Naturais, Campus VII, Universidade Federal do Maranhão, Avenida Dr. José Anselmo, 2008, São Sebastião, Codó, CEP 65400-000, MA, Brazil
| | - Gabriela C de Mattos
- Programa de Engenharia Química/COPPE - Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, CEP 21941-598, RJ, Brazil
| | - Martina C C Pinto
- Programa de Engenharia Química/COPPE - Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, CEP 21941-598, RJ, Brazil
| | - Luciana da S Dutra
- Programa de Engenharia Química/COPPE - Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, CEP 21941-598, RJ, Brazil
| | - Larissa L de A Carvalho
- Programa de Engenharia Química/COPPE - Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, CEP 21941-598, RJ, Brazil
| | - José Carlos C da S Pinto
- Programa de Engenharia Química/COPPE - Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, CEP 21941-598, RJ, Brazil
| | - Valéria Cristina S Pinheiro
- Laboratório de Entomologia Médica, Departamento de Química e Biologia, Universidade Estadual do Maranhão Campus Caxias, Praça Duque de Caxias, s/n, Morro do Alecrim, Caxias, CEP 65604-380, MA, Brazil
| | - Rosemary A Roque
- Instituto Nacional de Pesquisas da Amazônia, Laboratório de Controle Biológico e Biotecnologia da Malária e Dengue, Manaus, CEP 69060-001, AM, Brazil
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2
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Zhao D, Li Z, Xia J, Kang Y, Sun P, Xiao Z, Niu Y. Research progress of starch as microencapsulated wall material. Carbohydr Polym 2023; 318:121118. [PMID: 37479436 DOI: 10.1016/j.carbpol.2023.121118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 07/23/2023]
Abstract
Starch is non-toxic, low cost, and possesses good biocompatibility and biodegradability. As a natural polymer material, starch is an ideal choice for microcapsule wall materials. Starch-based microcapsules have a wide range of applications and application prospects in fields such as food, pharmaceuticals, cosmetics, and others. This paper firstly reviews the commonly used wall materials and preparation methods of starch-based microcapsules. Then the effect of starch wall materials on microcapsule properties is introduced in detail. It is expected to provide researchers with design inspiration and ideas for the development of starch-based microcapsules. Next the applications of starch-based microcapsules in various fields are presented. Finally, the future trends of starch-based microcapsules are discussed. Molecular simulation, green chemistry, and solutions to the main problems faced by resistant starch microcapsules may be the future research trends of starch-based microcapsules.
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Affiliation(s)
- Di Zhao
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China.
| | - Zhibin Li
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China
| | - Jiayi Xia
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China
| | - Yanxiang Kang
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China
| | - Pingli Sun
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China
| | - Zuobing Xiao
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China; School of Agriculture and Biology, Shanghai Jiaotong University, No. 800 Dongchuan Road, Shanghai 200240, China
| | - Yunwei Niu
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100 Haiquan Road, Shanghai 201418, China.
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Bustillos-Rodríguez JC, Ordóñez-García M, Ornelas-Paz JDJ, Sepúlveda-Ahumada DR, Zamudio-Flores PB, Acosta-Muñiz CH, Gallegos-Morales G, Berlanga-Reyes DI, Rios-Velasco C. Effect of High Temperature and UV Radiation on the Insecticidal Capacity of a Spodoptera frugiperda Nucleopolyhedrovirus Microencapsulated in a Matrix Based on Oxidized Corn Starch. NEOTROPICAL ENTOMOLOGY 2023; 52:104-113. [PMID: 36626092 DOI: 10.1007/s13744-022-01016-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
A multiple nucleopolyhedrovirus native isolate (SfCH32) of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) was encapsulated by spray-drying in a matrix based on oxidized corn starch without and with a fluorescent brightener. The microcapsules were exposed to UV radiation (365 nm) for 0, 2, 4, and 8 h at 25 °C or temperatures of 35, 40, and 45 °C for 8 h. The data obtained with temperatures 35, 40, and 45 °C were contrasted with those obtained at 25 °C. The microcapsules were evaluated for size, shape, and insecticidal capacity against third instar S. frugiperda larvae under laboratory conditions. The 82-84.2% of the encapsulating matrix, in a dry-weight basis, was recovered as NPV microcapsules of heterogeneous shape and size. The exposure to UV radiation and temperatures reduced significantly the insecticidal capacity of tested viruses; however, such capacity was higher for microencapsulated than for non-microencapsulated viruses. The non-encapsulated virus that had been exposed to 45 °C or maintained at UV radiation for 8 h showed the lowest insecticidal activity at 5th day post-inoculation, with a larvae mortality of 25.3 and 16%, respectively. The fluorescent brightener increased significantly the insecticidal capacity of encapsulated and non-encapsulated viruses, causing a mortality of 100% at that time point, and decreased the median lethal time independently of the incubation temperature and exposure time to radiation. The findings suggested that an encapsulating matrix based on oxidized corn starch might protect the insecticidal capacity of NPV under field conditions.
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Affiliation(s)
| | - Magali Ordóñez-García
- Centro de Investigación en Alimentación Y Desarrollo, A.C., Campus Cuauhtémoc, Chihuahua, Mexico
| | | | | | | | | | - Gabriel Gallegos-Morales
- Departamento de Parasitología Agrícola, Universidad Autónoma Agraria Antonio Narro, Saltillo, Coahuila, Mexico
| | | | - Claudio Rios-Velasco
- Centro de Investigación en Alimentación Y Desarrollo, A.C., Campus Cuauhtémoc, Chihuahua, Mexico.
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Yaakov N, Kottakota C, Mani KA, Naftali SM, Zelinger E, Davidovitz M, Ment D, Mechrez G. Encapsulation of Bacillus thuringiensis in an inverse Pickering emulsion for pest control applications. Colloids Surf B Biointerfaces 2022; 213:112427. [PMID: 35219966 DOI: 10.1016/j.colsurfb.2022.112427] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 01/23/2023]
Abstract
Here, we present an inverse Pickering emulsion-based formulation for Bacillus thuringiensis serovar aizawai (BtA) encapsulations utilized towards pest control applications. The emulsification was carried out by high shear homogenization process via ULTRA-TURRAX®. The water-in-mineral oil emulsions were stabilized by commercial hydrophobic silica. Different silica contents and water/oil ratios were studied. Stable emulsions were obtained at 2 and 3 wt% silica at 30% and 20% water volumes, respectively. The structure of the Pickering emulsions were characterized by laser scanning confocal microscopy and cryogenic scanning electron microscopy. The BtA cells, spores and crystals were encapsulated in the water droplets of the inverse Pickering emulsions. An emulsion composed of 3 wt% silica and 30% water was found to be the most suitable for encapsulation. The pest control efficiency of the encapsulated BtA against Spodoptera littoralis first instar larvae was tested. The studied BtA/emulsion system exhibited a mortality rate of 92%. However, the non-formulated BtA has shown 71% mortality, and the emulsion alone resulted in only 9% mortality. These findings confirm that an emulsion with encapsulated BtA can function as an efficient formulation for biopesticides.
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Affiliation(s)
- Noga Yaakov
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel
| | - Chandrasekhar Kottakota
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel; Department of Biochemistry and Biotechnology, Sri Krishnadevaraya College of Agricultural Sciences (SKCAS), Anantapurum, Andhra Pradesh, 515002, Affiliated to Acharya N.G. Ranga Agricultural University (ANGRAU), Guntur, Andhra Pradesh 522034, India
| | - Karthik Ananth Mani
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel
| | - Shoham Matsrafi Naftali
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel; Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel
| | - Einat Zelinger
- The Interdepartmental Equipment Unit, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel
| | - Michael Davidovitz
- Department of Entomology, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel
| | - Dana Ment
- Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel
| | - Guy Mechrez
- Department of Food Sciences, Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO), Volcani Institute, Rishon LeZion 7505101, Israel.
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5
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de Oliveira JL, Fraceto LF, Bravo A, Polanczyk RA. Encapsulation Strategies for Bacillus thuringiensis: From Now to the Future. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:4564-4577. [PMID: 33848162 DOI: 10.1021/acs.jafc.0c07118] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Bacillus thuringiensis (Bt) has been recognized for its high potential in the control of various agricultural pests. Developments in micro/nanotechnology have opened new perspectives for the production of more efficient formulations that can overcome some obstacles associated with its use in the field, such as formulation instability and loss of activity as a result of the degradation of pesticidal protein by its exposure to ultraviolet radiation, among other problems. This review describes current studies and recent discoveries related to Bt and processes for the encapsulation of Bt derivatives, such as Cry pesticidal proteins. Different techniques are described, such as extrusion, emulsion, spray drying, spray cooling, fluidized bed, lyophilization, coacervation, and electrospraying to obtain micro- and nanoparticulate systems. It is noteworthy that products based on microorganisms present less risk to the environment and non-target organisms. However, systematic risk assessment studies of these new Bt biopesticides are necessary, considering issues, such as interactions with other organisms, the formation of toxic secondary metabolites, or the interspecific transfer of genetic material. Given the great potential of these new formulations, a critical assessment is provided for their future use, considering the technological challenges that must be overcome to achieve their large-scale production for efficient agricultural use.
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Affiliation(s)
- Jhones L de Oliveira
- Department of Agricultural Production Sciences, Faculty of Agronomy and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, São Paulo 14884-900, Brazil
| | - Leonardo Fernandes Fraceto
- Institute of Science and Technology, São Paulo State University (UNESP), Avenida Três de Março 511, Alto da Boa Vista, Sorocaba, São Paulo 18087-180, Brazil
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 201, Colonia Chamilpa, Cuernavaca, Morelos 62210, Mexico
| | - Ricardo Antonio Polanczyk
- Department of Agricultural Production Sciences, Faculty of Agronomy and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, São Paulo 14884-900, Brazil
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6
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Pérez-Landa I, Bonilla-Landa I, Monribot-Villanueva J, Ramírez-Vázquez M, Lasa R, Ramos-Torres W, Olivares-Romero J, Barrera-Méndez F. Photoprotection and release study of spinosad biopolymeric microparticles obtained by spray drying. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2020.08.096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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Espinosa-Solis V, García-Tejeda YV, Leal-Castañeda EJ, Barrera-Figueroa V. Effect of the Degree of Substitution on the Hydrophobicity, Crystallinity, and Thermal Properties of Lauroylated Amaranth Starch. Polymers (Basel) 2020; 12:E2548. [PMID: 33143285 PMCID: PMC7692550 DOI: 10.3390/polym12112548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 11/30/2022] Open
Abstract
In this paper, we consider amaranth starch extracted from the seeds of Amaranthus hypochondriacus L. An amphiphilic character is conferred to the starch by a chemical modification, which involves an esterification by lauroyl chloride at three modification levels. The degree of substitution (DS) after the modification ranged from 0.06 to 1.16. X-ray photoelectron spectroscopy analysis confirmed the presence of fatty acyl chains on the surface of the esterified starches. The hydrophobicity of starches was confirmed by their adsorption isotherms, which showed a decrease in the moisture adsorption of lauroylated as DS increased. X-ray diffraction analysis revealed a higher crystallinity, which was observed in the two samples subjected to the highest levels of modification. A higher crystallinity is related to a higher gelatinization enthalpy. These results are in agreement with the thermal characterization obtained by differential scanning calorimetry (DSC). An inhibition of the retrogradation properties of lauroylated amaranth starches was also observed.
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Affiliation(s)
- Vicente Espinosa-Solis
- Coordinación Académica Región Huasteca Sur de la UASLP, Universidad Autónoma de San Luis Potosí, km 5, Carretera Tamazunchale-San Martín, 79960 Tamazunchale, Mexico;
| | - Yunia Verónica García-Tejeda
- Instituto Politécnico Nacional, Academia de Ciencias Básicas, UPIITA Avenida Instituto Politécnico Nacional No. 2580, Col. Barrio la Laguna Ticomán, 07340 Gustavo A. Madero, Mexico
| | - Everth Jimena Leal-Castañeda
- Instituto Politécnico Nacional, Academia de Matemáticas, ESIA. 07738, Col. Barrio la Laguna Ticomán, 07340 Gustavo A. Madero, Mexico;
| | - Víctor Barrera-Figueroa
- Instituto Politécnico Nacional, Sección de Estudios de Posgrado e Investigación, UPIITA, Avenida Instituto Politécnico Nacional No. 2580, Col. Barrio la Laguna Ticomán, 07340 Gustavo A. Madero, Mexico;
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Joshi PP, Van Cleave A, Held DW, Howe JA, Auad ML. Preparation of slow release encapsulated insecticide and fertilizer based on superabsorbent polysaccharide microbeads. J Appl Polym Sci 2020. [DOI: 10.1002/app.49177] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Prutha P. Joshi
- Department of Chemical EngineeringAuburn University Auburn Alabama USA
- Department of Polymer and Fiber EngineeringAuburn University Auburn Alabama USA
| | - Ashleigh Van Cleave
- Department of Crop, Soil and Environmental SciencesAuburn University Auburn Alabama USA
| | - David W. Held
- Department of Entomology and Plant PathologyAuburn University Auburn Alabama USA
| | - Julie A. Howe
- Department of Soil and Crop SciencesTexas A&M University College Station Texas USA
| | - Maria L. Auad
- Department of Chemical EngineeringAuburn University Auburn Alabama USA
- Department of Polymer and Fiber EngineeringAuburn University Auburn Alabama USA
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9
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Eski A, Demirbağ Z, Demir İ. Microencapsulation of an indigenous isolate of Bacillus thuringiensis by spray drying. J Microencapsul 2019; 36:1-9. [PMID: 30836029 DOI: 10.1080/02652048.2019.1572238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In this study, microencapsulation by spray drying was performed to protect spores and crystals of an indigenous isolate of Bacillus thuringiensis Se13 from environmental stress. The effects of wall material, inlet temperature, and outlet temperature on microencapsulation of Bt-Se13 were investigated using Taguchi's orthogonal array. The most suitable wall material determined as maltodextrin DE10. The optimum inlet and outlet temperatures of spray drier were determined as 160 °C and 70 °C, respectively. The number of viable spores, mean particle size, wetting time, percentage of suspensibility and moisture content of the product produced under optimum conditions were determined as 8.1 × 1011 cfu g-1, 13.462 µm, 25.22 s, 77.66% and 7.29%, respectively. As a result of efficiency studies on Spodoptera exigua in the laboratory conditions, the LC50 was determined as 1.6 × 104 cfu mL-1. Microencapsulated Bt-Se13 based bio-pesticide may be registered for the control of S. exigua and can be tested against other lepidopterans which share the same environment.
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Affiliation(s)
- Ardahan Eski
- a Faculty of Sciences, Department of Biology , Karadeniz Technical University , Trabzon , Turkey
| | - Zihni Demirbağ
- a Faculty of Sciences, Department of Biology , Karadeniz Technical University , Trabzon , Turkey
| | - İsmail Demir
- a Faculty of Sciences, Department of Biology , Karadeniz Technical University , Trabzon , Turkey
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10
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Coelho LM, Silva PM, Martins JT, Pinheiro AC, Vicente AA. Emerging opportunities in exploring the nutritional/functional value of amaranth. Food Funct 2018; 9:5499-5512. [DOI: 10.1039/c8fo01422a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Amaranthusspp. is a highly nutritive pseudocereal, rich in macronutrients and micronutrients, including vitamins and minerals.
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Affiliation(s)
| | - Pedro Miguel Silva
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
| | - Joana T. Martins
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
| | - Ana C. Pinheiro
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
- Instituto de Biologia Experimental e Tecnológica
| | - António A. Vicente
- CEB – Centre of Biological Engineering
- University of Minho
- 4710-057 Braga
- Portugal
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He X, Sun Z, He K, Guo S. Biopolymer microencapsulations of Bacillus thuringiensis crystal preparations for increased stability and resistance to environmental stress. Appl Microbiol Biotechnol 2017; 101:2779-2789. [PMID: 28050633 DOI: 10.1007/s00253-016-8070-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/12/2016] [Accepted: 12/17/2016] [Indexed: 10/20/2022]
Abstract
Parasporal crystals synthesized by Bacillus thuringiensis (Bt) have been widely used as microbial pesticides because of their toxicity to the larval stages of specific insects. However, parasporal crystals can be damaged by environmental stresses, such as high temperature, ultraviolet radiation, and desiccation. To reduce environmental susceptibility of parasporal crystals and extend the duration of their activity, we developed a new type of protection by making microcapsules of crystals (MCs). The microcapsules were self-assembled by alternate deposition (layer by layer) of low-cost chitosan and sodium alginate (or sodium carboxymethyl cellulose) on the crystal surface. Crystal toxins (Cry1Ac) were released from microcapsules at pH values above 9.0. Bioassay results demonstrated that microencapsulated preparations had larvicidal toxicity equivalent to the non-encapsulated form. Microencapsuled crystals were protected from environmental stresses such as high temperature and desiccation. The results indicate that microcapsule protection can enhance the efficacy of Bt in pest control, especially to Lepidoptera larvae that have a alkaline midgut.
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Affiliation(s)
- Xiaolin He
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhongqin Sun
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Kanglai He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Shuyuan Guo
- School of Life Science, Beijing Institute of Technology, Beijing, China.
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