Review and Perspectives of the Use of Alginate as a Polymer Matrix for Microorganisms Applied in Agro-Industry

Abstract

Alginate is a polysaccharide with the property of forming hydrogels, which is economic production, zero toxicity, and biocompatibility. In the agro-industry, alginate is used as a super absorbent polymer, coating seeds, fruits, and vegetables and as a carrier of bacteria and fungi as plant-growth promoters and biocontrol. The latter has a high impact on agriculture since the implementation of microorganisms in a polymer matrix improves soil quality; plant nutrition, and is functional as a preventive measure for the appearance of phytopathogenic. Additionally, it minimizes losses of foods due to wrong post-harvest handling. In this review, we provide an overview of physicochemical properties of alginate, some methods for preparation and modification of capsules and coatings, to finally describe its application in agro-industry as a matrix of plant-growth-promoting microorganisms, its effectiveness in cultivation and post-harvest, and its effect on the environment, as well as the prospects for future agro-industrial applications.

Polymeric Encapsulate of Streptomyces Mycelium Resistant to Dehydration with Air Flow at Room Temperature

“…Despite the reported instability of calcium alginate as an encapsulating support for biological material [ 38 ], it continues to be used preferentially for its biocompatibility and safety properties with biological material, as well as the possibility of improving the properties of the alginate either by mixing with other polymers or by including various additives in the alginate matrix [ 35 , 36 ]. In the present study, which was focused on the development of an encapsulated and dehydrated formulation of the Streptomyces CDBB1232 mycelium, of the different additives integrated into the calcium alginate matrix (trehalose, kaolin, and gum arabic), only the gum arabic protected the mycelium from the air-drying process.…”

“…The inconvenience of moisture removal with heat is the viability loss of the microbial cells because of their high sensitivity to heat or shear stresses, which usually damage the cellular membrane. Thus, the encapsulation of the biological material prior to dehydration is the strategy of interest and under study, considering the great variety of solid supports available (inorganic, organic, and polymeric) and the possibility of modifying their physicochemical properties by integrating into them the appropriate additive or additives ( Supplementary Table S2 ) [ 4 , 14 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ].…”

“…Of the known polymeric supports, alginate is one of the most commonly used in the encapsulation of microbial strains [ 34 , 35 , 36 , 37 ]. Alginate is a biocompatible, biodegradable, and nontoxic support that can be applied to encapsulate hydrophilic active substances.…”

Translating controlled release systems from biomedicine to agriculture

“…Such alginate hydrogels have been extensively explored for biomedical applications like wound healing (moist wound dressing), drug delivery (encapsulation of active substances for controlled release), and tissue engineering (scaffolding material) (Zhang et al, 2021c). In agriculture, alginate has been used to encapsulate, protect, and release growth-promoting microorganism soil inoculants (Martínez-Cano et al, 2022). Alginate has also been used to deliver nutrients (Fan et al, 2019).…”

Encapsulation with Natural Polymers to Improve the Properties of Biostimulants in Agriculture

“…Another use is the optimization of the fertilization process by encapsulating various fertilizers such as biochar [ 68 ] or biofertilizers [ 69 ]. In the agricultural industry, alginate is also used as a superabsorbent polymer to coat seeds, fruits, and vegetables and as a carrier of bacteria and fungi to promote plant growth and biocontrol [ 70 ]. Alginate hydrogel combined with some amino acids has been used as a coating agent, to be used in seeds for commercial applications, to stimulate the early growth of plants and thus leading to higher crop yields [ 71 ].…”