Abstract: A process is provided for the fermentative preparation of O-acetyl-L-serine. A microorganism strain, which is derived from a wild type and which exhibits an increased endogenous formation of O-acetyl-L-serine and an increased efflux of O-acetyl-L-serine as compared with the wild type, is cultured in a fermentation medium. A pH in the range from 5.1 to 6.5 is set in the fermentation medium.

Abstract: A process is provided for the fermentative preparation of O-acetyl-L-serine. A microorganism strain, which is derived from a wild type and which exhibits an increased endogenous formation of O-acetyl-L-serine and an increased efflux of O-acetyl-L-serine as compared with the wild type, is cultured in a fermentation medium. A pH in the range from 5.1 to 6.5 is set in the fermentation medium.

Abstract: An expression system can be regulated by acetate, pH and oxygen, which expression system includes a trans-acting regulator protein and a promoter which can be activated by this protein. Any desired structural genes are maximally expressed under the control of the expression system at an oxygen partial pressure, pO.sub.2, of 0-5% and a pH of 6.0-6.5, and in the presence of acetate at a concentration of 40-60 mM. There is also a process for preparing this expression system, and a process for using this expression system.

Abstract: The recombinant DNA according to the present invention contains a regulator region which is different from the pfl gene; a promoter region upstream from the gene which contains a -35/-10 promoter sequence; a regulator region upstream from the promoter region which contains a sequence (I) 5'-GAGATATGATCTATATCAATTTC-3' or a 23 base pair sequence which is at least 80% identical to positions 6-10 and 15-19 of said sequence (I) but not having C at position 8 and/or G at position 17. An expression vector according to the present invention contains a recombinant DNA according to the present invention ligated into a suitable vector molecule and methods are also described for expression the DNA.

Abstract: The invention relates to DNA fragments having the cyclodextrin glycosyltransferase structural gene, to vectors and microorganisms for expression and to a preparation process for the same.

Abstract: The alkalophilic bacteria (DSM 5853) possesses a maltopentaose producing amylase. The maltopentaose producing amylase, and its derivatives modified by gene manipulation, can be expressed in E. coli. These amylases facilitate the production of maltopentaose.

Abstract: A maltopentaose producing amylase, and its derivatives modified by gene manipulation, can be expressed in E. col. These amylases facilitate the production of maltopentaose.

Abstract: The invention relates to Aureobasidium pullulans strains which produce pullulan but virtually no melanin. A process for the preparation of these strains, and a preferred use, are also disclosed.

Abstract: The present invention provides a recombinant DNA, wherein it contains the consensus sequence: ##STR1## and a promoter which has the DNA sequence GGN.sub.10 GC. The present invention also provides a process for the isolation of this recombinant DNA, wherein a DNA sequence containing the consensus sequence is identified from a gene bank of a micro-organism, which contains a gene which is repressible by oxygen and inducible by formate under anaerobic conditions, isolated and combined with an appropriate promotor according to known methods.This recombinant gene can be used for the inducible and repressible expression of a foreign gene by bringing about the induction by formate under anaerobic conditions and the repression by oxygen.