METHOD FOR PRODUCING INVERTASE AND CITRIC ACID Russian patent published in 2018 - IPC C12P7/48 C12N9/24 

FIELD: chemistry.

SUBSTANCE: method for producing invertase and citric acid has been proposed. Method involves growing at 36 °C the seed mycelium Aspergillus niger – producer of citric acid, and deep fermentation medium at 32 °C based on a corn starch hydrolyzate containing a nitrogen source and mineral salts. Cultivation of the seed mycelium is carried out at the speed of mixing of the culture fluid in the first 12 h 120 rpm, after 12 hours and until the end of the process, 250 rpm under aeration conditions in the first 6 hours – 8 l/min, from 6 hours to 12 hours – 16 l/min, from 12 hours to 24 hours – 32 l/min. Deep fermentation is carried out with stirring on the first day at a speed of 250 rpm, on the second day at a speed of 300 rpm, on the third day until the end of the process at a speed of 400 rpm under aeration conditions on the first day 24–40 l/min, on the second day, 32–48 l/min, on the third day and until the end of the process, 40–56 l/min. Separate the culture fluid into mycelium and fermented solution, which is then separated by ultrafiltration through a membrane that holds a molecular weight of 15,000 into an invertase solution and a solution of citric acid. Method allows to obtain simultaneously invertase with an activity of 1.31 units/cm³ and a yield of 98.3 % and citric acid with a concentration of 110 g/dm³ and yield 92 %.

EFFECT: method allows to obtain simultaneously invertase and citric acid.

1 cl, 4 ex, 1 tbl