Stabilization of a chimeric malaria antigen in separation and purification through efficient inhibition of protease activity by imidazole

•Fast degradation was discovered for malaria antigen M.RCAg-1 after cell disintegration.•Imidazole and EDTA could efficiently inhibit the degradation.•A robust process was developed for large-scale production under GMP conditions.•The chimeric antigen was showed as monomer with a loose conformation.•M.RCAg-1 itself was stable and could elicit high levels of specific antibodies.