Abstract: The invention relates to a method for producing L-cystine by fermenting a microorganism strain in a fermentation medium, in which method L-cystine is precipitated in an amount of at least 70% relative to the total cysteine, characterized in that the O2 saturation of the fermentation medium is kept at least at 1% and at most at 40±3% during the formation of L-cystine.

Abstract: A method for the production of natural L-cysteine by fermentation in a production fermenter in which a microorganism strain is cultured in a fermentation medium, characterized in that the fraction of the compounds L-cysteine, L-cystine and thiazolidine in the fermentation medium is controlled in a targeted manner by an iron concentration of a maximum of 8 mg/l in the fermentation medium.

Abstract: A method for the production of natural L-cysteine by fermentation in a production fermenter in which a microorganism strain is cultured in a fermentation medium, characterized in that the fraction of the compounds L-cysteine, L-cystine and thiazolidine in the fermentation medium is controlled in a targeted manner by an iron concentration of a maximum of 8 mg/l in the fermentation medium.

Abstract: The invention relates to a method for producing L-cystine by fermenting a microorganism strain in a fermentation medium, in which method L-cystine is precipitated in an amount of at least 70% relative to the total cysteine, characterized in that the O2 saturation of the fermentation medium is kept at least at 1% and at most at 40±3% during the formation of L-cystine.

Abstract: The present invention relates to a process for producing a heterologous protein by means of an E. coli strain in a fermentation medium, in which an E. coli strain which has a mutation in the lpp gene or in the promoter region of the lpp gene, and contains a gene coding for a heterologous protein which is functionally linked to a signal sequence coding for a signal peptide, is fermented on an industrial scale in the fermentation medium, with the E. coli strain secreting the heterologous protein into the fermentation medium, and the protein being removed from the fermentation medium, wherein the heterologous protein comprises more than 70 amino acids.

Abstract: A method for the production of a chiral compound of the formula (I), R1 being identical or different and being H or an organic radical, where a biotransformation composition comprising a compound of the formula (II), an oxidoreductase, a redox cofactor and a cosubstrate are reacted forming the chiral compound of the formula (I) which is subsequently isolated.