recombinant plasmids, these recombinant plasmids containing bacteria, method for the production of fermented food products, animal feed, components derseben or proteins using these bacteria.

摘要

The cryptic Streptococcus cremoris Wg2 plasmid pWV01 (1.5 Md) was genetically marked with the chloramphenicol resistance (CmR) gene from pCI94, the erythromycin resistance (EmR) gene from pEI94 cop-6, the chloramphenicol acetyl transferase (CAT) gene, or combinations thereof to provide recombinant vector plasmids which can replicate in B. subtilis, E. coli and lactic streptococci. The CmR and EmR genes were expressed under regie of their own promoters, whereas the CAT gene was expressed under regie of the B. subtilis SP02 promotor. Instead of antibiotic resistance markers, the use of auxotrophic markers, e. g. the genes for lactose metabolism, is envisaged. Moreover, other genes were inserted into these plasmids and expressed in Streptococcus lactis, namely the bovine prochymosin gene described in EP-PA 0077109 (A2) under regie of B. subtilis SP02 promoter and the protease gene(s) from Streptococcus cremoris Wg2 plasmid pWV05. These and similar plasmids can be used to transform lactic acid bacteria to provide them with improved or new properties for the use in the fermentative preparation of food products, animal feedstuffs and ingredients thereof, as well as of proteins. A method for isolating other protease genes is provided which can be used instead of the pWV05-derived protease gene(s).