Abstract: Selective detection of microorganisms is achieved by a screening technique in which radioactively labeled, low-molecular-weight metabolites produced by microorganisms to be detected reach an adsorption medium through a semipermeable medium which passes the labeled metabolites but blocks the labeled incubation medium. The adsorption medium is then subject to analysis, such as autoradiography, to detect the presence of the labeled metabolites.

Abstract: Selective detection of microorganisms is achieved by a screening technique in which radioactively labeled, low-molecular-weight metabolites produced by microorganisms to be detected reach an adsorption medium through a semipermeable medium which passes the labeled metabolites but blocks the labeled incubation medium. The adsorption medium is then subject to analysis, such as antoradiography, to detect the presence of the labeled metabolites.

Abstract: Process for the production of L-carnitine utilizing a microorganism. The microorganism is cultivated with crotonobetaine and/or .gamma.-butyrobetaine in the presence of a growth substrate. The enriched L-carnitine is isolated. The microorganisms used are those which are capable of producing L-carnitine while not catabolizing it from crotonobetaine and/or .gamma.-butyrobetaine. The microorganisms can be obtained by the following selection method. Microorganisms which grow with betaine, .gamma.-butyrobetaine, crotonobetaine and L-carnitine as the C- and N-source are mutated in the conventional manner. From the culture obtained by cultivating of the mutated microorganisms, those microorganisms are selected which are stable, do not catabolize L-carnitine and do not grow on L-carnitine, crotonobetaine and .gamma.-butyrobetaine, but grow with betaine.

Abstract: Process for the production of 6-hydroxynicotinic acid from nicotinic acid. The hydroxylation is carried out enzymatically in the presence of a microorganism of the species Pseudomonas, Bacillus or Achromobacter, for example, Achromobacter xylosoxydans. Preferably the enzymatic hydroxylation is carried out at 20.degree. to 40.degree. C. and a pH of 5.5 to 9.0 under aerobic conditions. Also, preferably a 0.1 percent by weight solution up to a saturated (preferably a 0.5 to 10 percent by weight) nicotine acid solution is used.

Abstract: Process for the production of 6-hydroxynicotinic acid by biotechnological methods. Nicotinic acid is enzymatically hydroxylated in the presence of equivalent quantities of magnesium or barium ions with the help of nicotinic acid-hydroxylating microorganisms. The resultant magnesium or barium salt of the 6-hydroxynicotinic acid is separated from the reaction mixture. Then the 6-hydroxynicotinic acid is freed from the separated salts. Examples of the microorganism are the species Pseudomonas, Bacillus or Achromobacter, for example, Achromobacter xylosoxydans. Preferably the enzymatic hydroxylation is carried out at 20.degree. to 40.degree. C. and a pH of 5.5 to 9.0 under aerobic conditions.

Abstract: Process for the continuous production of L-carnitine by the microbiological method. A microorganism of the strain DSM No. 3225 (HK 1331b) type is cultivated in a bioreactor with crotonobetaine and/or .gamma.-butyrobetaine in the presence of a growth substrate. The culture fluid passes outside of the bioreactor in a circulation in which a separation of the cell is carried out. A quantity of cell-free solution, which is as large as the amount fed to the bioreactor as a substrate, is withdrawn from the bioreactor. The L-carnitine is separated from the cell-free solution.