Increased riboflavin production from activated bleaching earth by a mutant strain of Ashbya gossypii

• Published in: Journal of bioscience and bioengineering 2009-10, Vol.108 (4), p.325-329
• Main Authors: Tajima, Satoshi, Itoh, Yoko, Sugimoto, Takashi, Kato, Tatsuya, Park, Enoch Y.
• Format: Article
• Language: English
• Subjects: Ascomycota - genetics; Ascomycota - metabolism; Ashbya gossypii; Bacillus subtilis - metabolism; Biological and medical sciences; Biorefinery; Biotechnology; BLANCHISSEMENT; BLANQUEADURA; BLEACHING; Candida - metabolism; CATALASA; CATALASE; CHAMPIGNON; Citric Acid Cycle; DECHET; DESECHOS; FERMENTACION; FERMENTATION; Flavin Mononucleotide - metabolism; Flavin-Adenine Dinucleotide - metabolism; Fundamental and applied biological sciences. Psychology; FUNGI; Glyoxylates - metabolism; HONGOS; MONTMORILLONITA; MONTMORILLONITE; MONTMORILLONITES; Mutagenesis; MUTANT; MUTANTES; MUTANTS; Mutation; Plant Oils - metabolism; RIBOFLAVIN; Riboflavin - biosynthesis; RIBOFLAVINA; RIBOFLAVINE; Soil Microbiology; Spores, Fungal - genetics; Spores, Fungal - metabolism; Strain improvement; Waste activated bleaching earth; WASTES
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2009.04.021

The production of riboflavin from vegetable oil was increased using a mutant strain of Ashbya gossypii. This mutant was generated by treating the wild-type strain with N-methyl- N′-nitro- N-nitrosoguanidine (MNNG). Riboflavin production was 10-fold higher in the mutant compared to the wild-type strain. The specific intracellular catalase activity after 3 d of culture was 6-fold higher in the mutant than in the wild-type strain. For the mutant, riboflavin production in the presence of 40 mM hydrogen peroxide was 16% less than that in the absence of hydrogen peroxide, whereas it was 56% less for the wild-type strain. The isocitrate lyase (ICL) activity of the mutant was 0.26 mU/mg of protein during the active riboflavin production phase, which was 2.6-fold higher than the wild-type strain. These data indicate that the mutant utilizes the carbon flux from the TCA cycle to the glyoxylate cycle more efficiently than the wild-type strain, resulting in enhanced riboflavin production. This novel mutant has the potential to be of use for industrial-scale riboflavin production from waste-activated bleaching earth (ABE), thereby transforming a useless material into a valuable bioproduct.