Mariana Brondi1,2,Camila Florencio2,Luiz Mattoso2,Caue Ribeiro2,Cristiane Farinas1,2
Federal University of Sao Carlos1,Embrapa Instrumentation2
Mariana Brondi1,2,Camila Florencio2,Luiz Mattoso2,Caue Ribeiro2,Cristiane Farinas1,2
Federal University of Sao Carlos1,Embrapa Instrumentation2
The application of microbial inoculants in agriculture is a sustainable alternative to increase crops productivity and reduce the environmental problems related to the exacerbated use of agrochemicals. For a successful product, its formulation must provide protection to microorganism from its production to its final application on crops. The use of natural polysaccharides as encapsulation matrices has shown interesting results in the maintenance of cell viability. Matrices of cellulose and its derivatives (nanocellulose, carboxymethyl cellulose, among others) can be interesting to be used in this type of application, since these materials are abundant, renewable and biodegradable. Therefore, this study evaluated the encapsulation of spores of the biocontrol fungus <i>Trichoderma harzianum</i> in a green matrix of nanocellulose (CNC) and carboxymethyl cellulose (CMC), through a simple process of ionic cross-linking in a CaCl<sub>2</sub> solution. For beads production, two different polymeric dispersions with the spores (10<sup>9</sup> spores/g polymer) were evaluated: a 5% (w/v) CNC and a mixture of CNC (5%) with CMC (1.5% w/v) in a volume ratio of 3:1. These dispersions were dripped into the salt solution for beads formation. After the coagulation process, the beads were stored wet and under refrigeration. X-Ray microtomography and SEM micrograph showed the uniform distribution of the materials and highlighted the spore’s presence within the matrices, respectively. Shelf-life tests showed that the free microorganism presented a much higher viability loss over time than the ones encapsulated. Antagonistic tests showed that the <i>T. harzianum</i> spores, encapsulated in both matrices and stored for 1 year, were able to suppress the growth of the phytopathogenic fungus <i>Fusarium solani</i>, maintaining its effect as a biocontrol agent. Therefore, our results indicated that both CNC and the composite CNC:CMC are interesting sustainable matrices for improving microbial inoculants protection and shelf-life.