Enzymatic Studies of Riboflavin Oversynthesis in Eremothecium ashbyii

Abstract

SummaryMechanisms of riboflavin oversynthesis in a high flavinogenic mold, Eremoth ecium ashbyii, were examined in relation to growth, riboflavin formation and related syn thases, and medium pH with increasing culture periods. Growth reached maximum at 1dand then decreased, riboflavin formation proceeded rapidly up to 5d and approached al most a plateau region. The medium pH reached minimum at 1d and thereafter fairly rap idly increased until 3d, then gradually increased to 7d after cultivation. The crude enzyme solution from the mycelia at specified culture periods was run through a column of Sepha dex G-200, indicating two riboflavin synthase activities on the chromatogram. The fluctua tion of the growth and the specific activities of the two enzymes were examined with in creasing culture periods, which showed that the heavy enzyme may be a constitutive one and that the light enzyme may be concerned with the oversynthesis of riboflavin in E. ash byil. The heavy enzyme was then purified by 49-fold after dialysis of the ammonium sulfate precipitate by a series of column chromatographies with Sephadex G-200, hydroxyapatite, DEAE-Sepharose A-50 and DEAE-cellulose. The purified enzyme which was treated with weak alkaline solution was broken into the light enzyme, showing two bands on an acryl amide disc gel electrophoresis. The relation of the heavy and the light enzymes to the over synthesis of riboflavin in E, ashbyii was discussed.

Impact of different fermentation characteristics on the production of mycelial biomass, extra-cellular polysaccharides, intra-cellular polysaccharides, and on the antioxidant activities of Cordyceps militaris (L.) Fr. (strains AG-1, PSJ-1)

“…During the fermentation, C. militaris grows in liquid suspension, which is thought to be the best way to produce complex organic compounds including cordycepin (Mao et al, 2005). Vegetable oils can enhance growth rates of mycelium in liquid culture (Schisler & Volkoff, 1977) and reports suggest that oils and fatty acids promote production of fungal metabolites (Kojima et al, 1972).…”