THE ENRICHMENT OF RHIZOBIUM FROM A MODEL SYSTEM USING IMMUNOMAGNETIC SEPARATION

Using immunomagnetic separation up to 200-fold enrichment of Rhizobium strains from mixtures has been achieved. This is the first report successfully using indirect separation, in which antiserum was attached to cells rather than immunomagnetic beads, thus allowing unfractionated serum to be employed. Optimal reaction conditions have been defined and the critical stages identified. Incubation of cells with immunomagnetic beads for an hour is needed to maximise cell recovery from suspension and at least six washing steps are needed to remove loosely bound cells from the beads so that non-specific binding is minimised. It is also evident that some anti-Rhizobium sera are better than others at promoting cell recovery, although the reason for this has not been found.