DK606789A - RIBOFLAVIN PRODUCING MICRO-ORGANIC STOMES, PROCEDURES FOR SELECTING AND FERMENTING THESE STEMS - Google Patents

Abstract

The patent describes strains of the yeast genus Candida famata which can produce 10 g of riboflavin per litre within the course of 6 days, and, in particular, the strains which are identified by the ATCC registration numbers 20849 and 20850. Riboflavin yields of more than 20 g/litre are achieved within the course of 200 hours. The strains according to the invention have an increased sensitivity towards iron inhibition of flavinogenesis and increased riboflavin production per cell in association with increased concentrations of iron in the fermentation medium. The invention also relates to a process for selecting improved microorganisms which are resistant towards growth inhibition by spent medium. These selected microorganisms are subsequently tested for riboflavin overproduction. In addition to this, the patent deals with a selection method in which mutated microorganisms are cultured in the presence of tubercidin, which is a purin analogue. Mutant strains which are resistant to tubercidin are subsequently tested for riboflavin overproduction. In addition to this, the patent deals with a method for preparing riboflavin by culturing strains of riboflavin-overproducing microorganisms in a fermentation medium. Increased riboflavin production can be achieved in association with increased iron concentrations in the nutrient medium. The fermentation is carried out and, after cell growth has declined, the riboflavin is recovered from the fermentation medium.