COMPARAISON DE L’ACTIVITE PROTEASIQUE DES SOUCHES DE Bacillus thuringiensis STRAINS

Abstract

During this work, a screening among 4 receiving host cells of B. thuringiensis was realized in order to distinguish the least producing proteolytic enzymes strain. We found that the proteolytic activity of the B. thuringiensis subspecies israelensis 14T and 4Q7 after 48 hours is about 165.9 IU and at 138.08 IU, respectively. While the B. thuringiensis subspecies kurstaki HD1cryB and the cured BUPM95 is about 95.36 IU and 400.62 IU, respectively. Therefore, HD1cryB and 4Q7 were chosen as hosts cells for the pHT-Blue-vip3Aa16 plasmid. The electroporation of B. thuringiensis strains was verified via the PCR amplification since a band of 820 pb corresponding to the vip3Aa16 gene was detected. The synthesis of the protein Vip3Aa16 from the recombinant strains HD1cryB (pHT-Blue-vip3Aa16) and 4Q7 (pHT-Blue-vip3Aa16) demonstrated that HD1cryB proteases did not affect the Vip3Aa16 expression rate. Thus, the B. thuringiensis HD1cryB could be a very suitable host strain.