A comparative study of different factors involved in mass cultivation of rhizobia, using shakers and fermentors.

Growth was proportionally linear to increasing load of inoculum although an inoculum load of 6 to 8% was optimum to obtain uniform number of viable cells, beyond which the number of viable cells did not increase. From the point of view of contamination with other microorganisms and the nodulating ability of cultures, fermentor cultures were better than shake cultures. When growth of Rhizobium was studied in relation to unit of mannitol consumed, it was observed that fermentors are more economical for culturing rhizobia than shakers.