Parameter evaluation for developing phosphate-solubilizing Bacillus inoculants

• Published in: Brazilian journal of microbiology Vol. 55; no. 1; pp. 737 - 748
• Main Authors: Bini, Daniel, Mattos, Bianca Braz, Figueiredo, José Edson Fontes, dos Santos, Flávia Cristina, Marriel, Ivanildo Evodio, dos Santos, Cristiane Alcantara, de Oliveira-Paiva, Christiane Abreu
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-03-2024; Springer Nature B.V
• Subjects: Accumulation; Activated carbon; Activated charcoal; Availability; Bacillus pumilus; Bacillus subtilis; Biomedical and Life Sciences; Carboxymethyl cellulose; Carboxymethylcellulose; Cassava; Cellulose; Charcoal; Corn; Crop yield; Food Microbiology; Inoculum; Life Sciences; Medical Microbiology; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Mineralization; Mixtures; Mycology; Parameters; Peat; Phosphorus; Productivity; Rock phosphate; Room temperature; Shelf life; Soil and Agricultural Microbiology - Research Paper; Storage conditions; Strains (organisms); Zea mays; Phosphate-solubilizing bacteria; Shelf life; Phosphate fertilizers; Maize yield; L; Zea mays L
• ISSN: 1517-8382; 1678-4405; 1678-4405
• DOI: 10.1007/s42770-023-01182-0

Bacterial inoculants have been used in agriculture to improve plant performance. However, laboratory and field requirements must be completed before a candidate can be employed as an inoculant. Therefore, this study aimed to evaluate the parameters for inoculant formulation and the potential of
Bacillus
subtilis
(B70) and
B
.
pumilus
(B32) to improve phosphorus availability in maize (
Zea mays
L.) crops. In vitro experiments assessed the bacterial ability to solubilize and mineralize phosphate, their adherence to roots, and shelf life in cassava starch (CS), carboxymethyl cellulose (CMC), peat, and activated charcoal (AC) stored at 4 °C and room temperature for 6 months. A field experiment evaluated the effectiveness of strains to increase the P availability to plants growing with rock phosphate (RP) and a mixture of RP and triple superphosphate (TS) and their contribution to improving maize yield and P accumulation in grains. The B70 was outstanding in solubilizing RP and phytate mineralization and more stable in carriers and storage conditions than B32. However, root adherence was more noticeable in B32. Among carriers, AC was the most effective for preserving viable cell counts, closely similar to those of the initial inoculum of both strains. Maize productivity using the mixture RPTS was similar for B70 and B32. The best combination was B70 with RP, which improved the maize yield (6532 kg ha
−1
) and P accumulation in grains (15.95 kg ha
−1
). Our results indicated that the inoculant formulation with AC carrier and B70 is a feasible strategy for improving phosphorus mobilization in the soil and maize productivity.