Process for the fermentative preparation of metabolic products and for the nucleotide sequences encoding for the sod gene

Abstract

The invention provides nucleotide sequences encoding for the sod gene and a process for the fermentative preparation of nucleotides, vitamins and L-amino acids, in particular L-lysine, using coryneform bacteria in which the sod gene is amplified.

1 . Preferably recombinant DNA, from Corynebacterium, which is replicatable in coryneform microorganisms and which contains at least the nucleotide sequence which encodes for the sod gene represented in SEQ-ID-No. 1.  
     
     
         2 . Replicable DNA in accordance with  claim 1  comprising 
 (i) the nucleotide sequence, shown in SEQ-ID-No.1, or  
 (ii) at least one sequence which corresponds to the sequence (i) within the region of degeneration of the genetic code, or  
 (iii) at least one sequence which hybridizes with the sequence which is complementary to sequence (i) or (ii) and optionally  
 (iv) functionally neutral sense mutations in (i).  
 
     
     
         3 . An amino acid sequence for the protein derived from the nucleotide sequences in accordance with claims  1  or 2, represented in SEQ-ID-No. 2.  
     
     
         4 . Coryneform microorganisms, in particular the genus Corynebacterium, transformed by the introduction of one or more of the replicatable DNA's in accordance with one of claims  1  or  2 .  
     
     
         5 . Shuttle vector pMM23, characterised by the restriction chart given in FIG. 1 and deposited in  Escherichia coli  under the name DSM 12860.  
     
     
         6 . A process for increasing the superoxide dismutase activity in coryneform bacteria, wherein the sod gene, or nucleotide sequences encoding therefor, is amplified, in particular overexpressed.  
     
     
         7 . A process for preparing metabolic products, in particular L-lysine, by fermentation of coryneform bacteria, wherein bacteria are used in which the sod gene or nucleotide sequences encoding therefor is amplified, in particular overexpressed.  
     
     
         8 . A process according to  claim 7 , wherein bacteria are used in which other genes in the biosynthetic pathway of the desired metabolic product are amplified.  
     
     
         9 . A process according to  claim 7 , wherein bacteria are used in which metabolic pathways which reduce production of the desired metabolic product are at least partly switched off.  
     
     
         10 . A process according to  claims 7  to  9 , wherein a strain which has been transformed with a plasmid vector is used and the plasmid vector carries the nucleotide sequence encoding for the sod gene.  
     
     
         11 . A process according to  claim 9 , wherein bacteria transformed with the plasmid vector pMM23, deposited in  Escherichia coli  under the number DSM 12860, is used.  
     
     
         12 . A process according to one or more of the preceding Claims, wherein coryneform bacteria are used which produce nucleotides, vitamins and amino acids.  
     
     
         13 . A process according to one or more of the preceding Claims, wherein the coryneform bacteria used produce L-lysine.  
     
     
         14 . A process according to  claim 8  to produce nucleotides, wherein the purF gene encoding for glutamine-PRPP-amidotransferase is simultaneously overexpressed.  
     
     
         15 . A process according to  claim 8  to prepare nucleotides, wherein the carAB gene encoding for carbamoyl synthetase is simultaneously overexpressed.  
     
     
         16 . A process according to  claim 8  for preparing D-pantothenic acid, wherein the panD gene encoding for aspartate decarboxylase is simultaneously overexpressed.  
     
     
         17 . A process according to  claim 8  for preparing L-lysine, wherein the dapA gene encoding for dihydrodipicolinate synthase is simultaneously overexpressed.  
     
     
         18 . A process according to  claim 8  for preparing L-lysine, wherein a DNA fragment promoting S-(2-aminoethyl)cysteine resistance is simultaneously amplified.  
     
     
         19 . A process for the fermentative preparation of the desired metabolic products in accordance with one or more of the preceding Claims, wherein the following steps are performed: 
 a) fermentation of the coryneform bacteria which produce the desired metabolic product, in which at least the sod gene is amplified,    b) enrichment of the desired metabolic product in a medium or in the cells of the bacteria and    c) isolation of the desired product.    
     
     
         20 . A process for the fermentative preparation of L-amino acids according to  claim 19 , wherein the following steps are performed: 
 a) fermentation of the coryneform bacteria which produce the desired metabolic product, in which at least the sod gene is amplified,    b) enrichment of the desired metabolic product in a medium or in the cells of the bacteria and    c) isolation of the desired product.    
     
     
         21 . A process for the fermentative preparation of D-pantothenic acid according to  claim 19 , wherein the following steps are performed: 
 a) fermentation of the coryneform bacteria which produce D-pantothenic acid, in which at least the sod gene is amplified,    b) enrichment of D-pantothenic acid in a medium or in the cells of the bacteria and    c) isolation of this acid.