AN OPTIMIZED PROCESS FOR MANUFACTURING AN AZOSPIRILLUM INOCULANT FOR CROPS

An optimized process for manufacturing a crop moculant was developed with an Azospirillum lipoferum strain. This process involves the entrapment of living cells in alginate beads and dehydration. The influence of several parameters, alginate concentration, additions of adjuvants at different stages, dilution of culture broth, water activity and dehydration method on bacterial survival is presented. The highest survival was obtained by addition of skim milk and controlled air-dehydration of the alginate beads. Finally, a powdered inoculant was obtained, containing more than 10 billion cells/g, easy to store and to handle, which can be used in the field as a microgranule or as a seed coating. Furthermore, the biodegradability insures that there is no environmental pollution. © 1990 Springer-Verlag.