Sodium Alginate-Gelatin Nanoformulations for Encapsulation of Bacillus velezensis and Their Use for Biological Control of Pistachio Gummosis.

Mojde Moradi Pour,Roohallah Saberi Riseh,Yury A Skorik

doi:10.3390/ma15062114

Mojde Moradi Pour, Roohallah Saberi Riseh + Show 1 more

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https://doi.org/10.3390/ma15062114

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Abstract

Biopolymer-based nanocomposites are favorable materials for the encapsulation of biofertilizers and biocontrol agents. In this research, sodium alginate, a widely used natural polymer, was extracted and purified from Macrocystis pyrifera. Its composition was confirmed using 1H NMR and FTIR analyses, and its molecular weight and mannuronic acid/guluronic acid ratio were obtained. Sodium alginate–gelatin microcapsules enriched with carbon nanotubes and SiO2 nanoparticles were prepared to encapsulate Bacillus velezensis, and the biological effects of this formulation on the control of pistachio gummosis and growth parameters were investigated. Microscopy examination showed that the microcapsules had quite globular shapes. XRD confirmed the occurrence of an electrostatic interaction when sodium alginate was blended with gelatin. The survival rate of the encapsulated bacteria was about 107 CFU/mL and was maintained after one year of storage. The aim of this study was to achieve a unique formulation containing beneficial bacteria and nanoparticles for the synergistic control of Phytophthora drechsleri.

Highlights

Biopolymers are natural polymers produced by fauna, flora, and microorganisms.Many biopolymers, such as carbohydrates, proteins, and lipids [1], are useful in encapsulation technology, and carbohydrate polymers play a key role [2,3]
The growth inhibition halo caused by the B. velezensis bacterial strain was 1.6 cm in diameter (Figure 2)
We investigated the plant growth-promoting (PGP) activity of B. velezensis in pistachio plants, and we examined the benefits of encapsulating the plant growth-promoting rhizobacteria (PGPR) in microcapsules prepared with a biopolymer (ALG-gelatin) and nanoparticles (SiO2 and Carbon nanotubes (CNTs))

Summary

Introduction

Biopolymers are natural polymers produced by fauna, flora, and microorganisms Many biopolymers, such as carbohydrates (e.g., sodium alginate, gellan gum, xanthan gum, chitosan, starch), proteins (e.g., gelatin, whey protein), and lipids (e.g., types of butter) [1], are useful in encapsulation technology, and carbohydrate polymers play a key role [2,3]. The encapsulation of microorganisms is attracting attention as a method to improve the efficiency of beneficial microorganisms [4–7]. The high cost of obtaining this naturally occurring polysaccharide polymer limits its commercial use. By contrast, another natural polymer, gelatin, has the benefits of low cost and biodegradability, and many researchers reported that encapsulation using a combination of ALG and gelatin is more efficient than using ALG alone [12]. Encapsulating different formulations of microbial agents using these agents can play an important role in the biological control of plant diseases

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