Spray-Drying Microencapsulation of Bacillus megaterium in PVA/Cationic Starch/Zinc Oxide for Promoting Growth and Zinc Availability in Soybean Plants

Author(s)

Lodi, Ludimila Araujo ; Borges, Roger ; Lopes, Marina Momesso ; Graciano, Vanessa Araujo ; Bortoletto-Santos, Ricardo ; Barud, Hernane S. ; de Oliveira-Paiva, Christiane Abreu ; Ribeiro, Caue ; Farinas, Cristiane Sanchez

• Document type: Journal article
• Source: ACS AGRICULTURAL SCIENCE & TECHNOLOGY; v. N/A, p. 13-pg., 2024-11-11.

Abstract

Zinc (Zn) is essential for plant development and its deficiency can reduce agricultural productivity. Nutrient-solubilizing microorganisms offer a promising solution to enhance the zinc availability for plants. However, directly applying these microorganisms in the field presents challenges such as cell viability loss. Here, we developed a formulation using poly(vinyl alcohol) (PVA), cationic starch (CS), and zinc oxide (ZnO) for microencapsulating Bacillus megaterium via spray drying. Our results showed that B. megaterium effectively solubilizes zinc oxide. The PVACS-ZnO matrix provided a favorable environment for the growth and development of B. megaterium, releasing cells in quantities exceeding initial inoculation (10 log10 CFU/g). Additionally, it protected the cells against adverse field conditions, maintaining bacterial viability after heat (50 degrees C/48 h), UV light (95% after 180 min), and fungicide/insecticide exposure (99% after 2 h), unlike free bacteria. Accelerated shelf life tests indicated prolonged stability of PVACS-ZnO microspheres, with double the estimated shelf life (14 months) compared to free bacteria (6 months). In greenhouse experiments, the formulation increased aerial and root biomass of soybean plants, and enhanced phosphorus and zinc absorption. These findings indicate that PVASC-ZnO formulations offer a promising strategy for encapsulating microorganisms and enhancing zinc availability, resulting in an effective and environmentally friendly biofertilizer product. (AU)

• FAPESP's process: 17/50334-3 - Institutional research development plan (PDIp): modernization and adequacy of strategic multi-user units of the Instituto Biológico
• Grantee: Ana Eugênia de Carvalho Campos
• Support Opportunities: Research Grants - State Research Institutes Modernization Program
• FAPESP's process: 23/09673-0 - Development of wet mechanochemical treatment for the use of WTP sludge as raw material for the production of controlled-release fertilizers
• Grantee: Roger Borges
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• FAPESP's process: 20/12210-3 - Development of technological alternatives for the use of ETA sludge as raw material for the production of controlled release fertilizers
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE
• FAPESP's process: 21/11965-3 - Center for the sustainable management of pests, diseases and weeds
• Grantee: Mário Eidi Sato
• Support Opportunities: Research Grants - Science Centers for Development
• FAPESP's process: 24/09631-8 - Multifunctional bioinputs based on microorganisms and amino acids with plant nutrition and biostimulation properties for application in agriculture
• Grantee: Cristiane Sanchez Farinas
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/01549-8 - Development of wet mechanochemical treatment for the use of WTP sludge as raw material for the production of controlled-release fertilizers
• Grantee: Cauê Ribeiro de Oliveira
• Support Opportunities: Regular Research Grants