Abstract
Microencapsulation of plant-beneficial bacteria, such as pink pigmented facultative methylotrophs (PPFM), may greatly extend the shelf life of these Gram-negative microorganisms and facilitate their application to crops for sustainable agriculture. A species of PPFM designated Methylobacterium radiotolerans was microencapsulated in cross-linked alginate microcapsules (CLAMs) prepared by an innovative and industrially scalable process that achieves polymer cross-linking during spray-drying. PPFM survived the spray-drying microencapsulation process with no significant loss in viable population, and the initial population of PPFM in CLAMs exceeded 1010 CFU/g powder. The PPFM population in CLAMs gradually declined by 4 to 5 log CFU/g over one year of storage. The extent of alginate cross-linking, modulated by adjusting the calcium phosphate content in the spray-dryer feed, did not influence cell viability after spray-drying, viability over storage, or dry particle size. However, particle size measurements and light microscopy of aqueous CLAMs suggest that enhanced crosslinking may limit the release of encapsulated bacteria. This work demonstrates an industrially scalable method for producing alginate-based inoculants that may be suitable for on-seed or foliar spray applications.
Highlights
A s knowledge of plant-microbe interactions expands, commercial interests aspire to harness these interactions to advance sustainable agriculture
This study demonstrates a novel and highly scalable process to microencapsulate Gram-negative rhizobacteria in a cross-linked alginate matrix, using M. radiotolerans as a model pink pigmented facultative methylotrophs (PPFM)
While microencapsulation in dry cross-linked alginate has been proposed for a variety of plant-beneficial bacteria, including PPFMs,[20] the method employed in this study streamlines the microencapsulation process using existing industrial equipment
Summary
A s knowledge of plant-microbe interactions expands, commercial interests aspire to harness these interactions to advance sustainable agriculture While rhizobacteria such as Azospirillum and Pseudomonas have been applied to crops for decades to facilitate nitrogenfixation and to enhance protection against plant pathogens,[1] other rhizobacteria such as pink pigmented facultative methylotrophs (PPFMs) have only recently drawn attention for their beneficial interactions with plants and their potential application in modern agriculture.[2]. Application of Methylobacterium radiotolerans to jatropha, a potential biodiesel crop, dramatically increased seed yield while improving biomass production.[10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
