Amino acids, in particular L-lysine and L-glutamate, are used in human medicine, in the pharmaceuticals industry, in the foodstuffs industry, but in particular in animal nutrition.
It is known that amino acids are produced by fermentation from strains of coryneform bacteria, in particular Corynebacterium glutamicum. Because of their great importance, work is constantly being undertaken to improve the preparation methods. Improvements to the methods can relate to fermentation measures, such as e. g. stirring and supply of oxygen, or the composition of the nutrient media, such as e. g. the sugar concentration during the fermentation, or the working up to the product form by e.g. ion exchange chromatography, or the intrinsic output properties of the microorganism itself.
Methods of mutagenesis, selection and mutant selection are used to improve the output properties of these microorganisms. Strains which are resistant to antimetabolites, such as e.g. the lysine analogue S-(2-aminoethyl)-cysteine, or are auxotrophic for metabolites of regulatory importance and produce L-amino acids, such as e. g. L-lysine or L-glutamate, are obtained in this manner.
Methods of the recombinant DNA technique have also been employed for some years for improving the strain of Corynebacterium strains which produce amino acids, by amplifying individual amino acid biosynthesis genes and investigating the effect on the amino acid production. Review articles in this context are to be found, inter alia, in Kinoshita (xe2x80x9cGlutamic Acid Bacteriaxe2x80x9d, in: Biology of Industrial Microorganisms, Demain and Solomon (Eds.) I.B.R., Benjamin Cummings, London, UK, 1985, 115-142), Hilliger (BioTec 2, 40-44 (1991)) I.B.R., Eggeling (Amino Acids 6:261-272 (1994)) I.B.R., Jetten and Sinskey (Critical Reviews in Biotechnology 15, 73-103 (1995)) I.B.R. and Sahm et al. (Annuals of the New York Academy of Science 782, 25-39 (1996)) I.B.R.
The object of the present invention was to provide new aids for improved fermentative preparation of amino acids, in particular L-lysine and L-glutamate.
This object is achieved by a genetically modified coryneform bacterium, the cma gene of which, which codes for cyclopropane-mycolic acid synthase, is amplified.
Amino acids, in particular L-lysine and L-glutamate, are used in human medicine, in the pharmaceuticals industry, in the foodstuffs industry, and in particular in animal nutrition. There is therefore a general interest in providing new improved methods for the preparation of amino acids, in particular L-lysine and L-glutamate.
When L-lysine or lysine and L-glutamate or glutamate are mentioned in the following, not only the bases but also the salts, such as e. g. lysine monohydrochloride or lysine sulfate, are also meant by this.
The new DNA sequence of C. glutamicum which codes for the cma gene and which as a constituent of the present invention is SEQ ID NO 1 and related sequences. The amino acid sequence of the corresponding gene product of the cma gene has furthermore been derived from the present DNA sequence. The resulting amino acid sequence of the cma gene product is SEQ ID NO 2 and related sequences.