[The biosynthesis of kojic acid by Aspergillus flavus Link strains isolated from feed].

An ability of 98 strains of Aspergillus flavus link to form kojic acid has been studied. Fourteen strains with high activity of synthesis (the content of kojic acid in the nutrient medium was 28-32 mg/ml on the 14th day of cultivation) have been selected. The specific kojiforming activity of kojic acid formation of aspergilli strains was maximal during exponential growth phase. Initial value of pH of growth medium providing maximum intensity of kojic acid biosynthesis (4.5-5.5). Such carbohydrates as glucose, saccharose, maltose and galactose proved to be of the most use. Comparatively high yield of kojic acid (8.5-9.5 g/kg) was obtained by the method of solid-phase fermentation on the grain and grain-forage with high amount of proteins and carbohydrates (maize, oats, rye and barley grain). A method of production of crystalline chemically pure kojic acid was modified. The preparation toxicity was studied on chickens. A number of clinical and pathanatomical symptoms characteristic of kojitoxicosis of agricultural animals and poultry have been registered.