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Abstract
The present work is aiming to propose a new formulation of Bacillus spp. strains in combination with natural phosphate by spray drying. Bacillus sp. strain (SS0306) has proven its plant growth promoting effectiveness mainly on phosphate solubilization capacity and improved nutrient assimilation in wheat plants. Bacterial microencapsulation methods involved spray-drying assays that were conducted using 5% of rock phosphate with 2%–10% of maltodextrin and 2% of alginic acid sodium salt. The process parameters were also optimized with inlet temperature (155 °C), feed rate (9 min mL−1), and spray air rate (413.87 L h−1). Results showed a moisture content of the dried powders ranged between 2% and 8% and satisfactory viability levels of Bacillus sp. SS0306 (105–106 CFU g−1) after drying assay, with the survival rates between 61.56% and 64.18%. Optimized process reached 50.30% and 65.10% for the product yield, with 1.25 ± 0.006 mg g−1 of higher Pi content observed in rock phosphate formulations based on Alg 2%. The present study opens new possibilities to develop Bio-mineral fertilizers using the spray drying approach.
Acknowledgement
The Authors would like to acknowledge the support through the R&D Initiative – Appel à projetsautour des phosphates APPHOS – sponsored by OCP (OCP Foundation, R&D OCP, Mohammed VI Polytechnic University, National Center of Scientific and technical Research CNRST, Ministry of Higher Education, Scientific Research and Professional Training of Morocco MESRSFC) under the project entitled *Bioformulation d’un Consortium de Microorganismes solubilisateurs du phosphate: effets bénéfiques sur la croissance et la protection des plantes*, project ID *BIO-BIZ-01/2017*.
Disclosure statement
The authors declare no conflict of interest.