METHOD FOR PREPARATION OF CITRIC ACID, ?-AMILASE AND GLUCOAMYLASE Russian patent published in 2009 - IPC C12P7/48 C12N9/30 C12N9/34 

FIELD: chemistry.

SUBSTANCE: method provides the hydrolysis of starch-containing raw materials, following adding of the mineral salts to the obtained hydrolysate and medium fermentation with acid-forming fungi Aspergillus niger. The hydrolysis is carried out with ferment preparate of bacterial α-amilase at increased temperature and excessive pressure. The starch-containing raw material are rice flour allowed beforehand in the water at 20-25°C during 10-12 hrs. in amount of 205.3-235.7 g and rye flour in amount of 232.0-290.6 g. The carbon and nitrogen ratio in the obtained rice flour suspension is provided respectively equal (20.0-23.0):1, in rye flour suspension - (14.0-16.0):1. The ferment preparate is added up to achieving of carbon source dextrose equivalent value 35-40%. The sugars conversion to citric acid is 86.7-93.2%. α-amilase and glucoamylase activity is respectively 4.5-6.2 units A,C/cm³ and 160-180 units Gl.C/cm³.

EFFECT: increase of α-amilase and glucoamylase yield while maintaining the high yield of citric acid.

1 tbl, 7 ex