RESUMO
Enzymatic modification of meat with a high content of connective tissue is an effective mean, allowing to improve its properties and expand its use. Microbial enzymes have been extensively investigated as meat tenderizers. Compliance with safety requirements in terms of forecasting the development of various risks is essential for the use of these enzymes in food industry. The method of producing recombinant protease as a potential candidate for applications on meat tenderization was described in the article. The aim of this study was the production of recombinant Pichia pastoris with M9 peptidase gene from Aeromonas salmonicida. Material and methods. Objects: peptidase gene M9 (GenBank: CP000644.1 ASA_3723) Aeromonas salmonicida (strain of laboratory collection, isolated from the surface of raw meat), the vector plasmid pPic9K, competent E. coli DH5α cells, competent Pichia pastoris GS115 cells, culture fluid (QOL) from recombinant Pichia pastoris clones, beef shank samples. To obtain a recombinant strain, genetic engineering methods, the PCR method, and the bacteriological method were used. Polyacrylamide gel electrophoresis was used to separate and analyze the components of the supernatant. Enzyme activity was evaluated by HPLC-MS/MS using synthesized peptides. The impact of the supernatant from recombinant clones on the connective tissue of raw meat was assessed by histological method. Results and discussion. A metalloprotease M9 gene was cloned from the Aeromonas salmonicida (2748 bp) and expressed in Pichia pastoris. The molecular mass of the recombinant protein was estimated to be 120 kDa by SDS-PAGE. Histological analyses of the control and enzyme treated beef samples showed degradation intramuscular connective tissue, suggesting its effectiveness on meat tenderization. Conclusion. The recombinant strain Pichia pastoris, which produces the recombinant M9 peptide of Aeromonas salmonicida, has a specific enzymatic activity against collagen, the main component of the connective tissue of meat. The obtained recombinant peptidase M9 can be used as an enzyme softener of raw meat with a high content of connective tissue.
