method and device for vergaren of kohlehydrathaltigem nahrsubstrat

摘要

1530370 Citric acid by fermentation STANDARD MESSO DUISBURG GES FUR CHEMIETECHNIK mbH & CO 10 Sept 1976 [27 Sept 1975] 37564/76 Heading C2C [Also in Divisions C6 and F4] A process for the fermentation of a nutrient substrate, exemplified by the fermentation of molasses by Aspergillus to produce citric acid, involves inoculating the substrate with the ferment in a germ-free chamber, allowing the ferment in a germination phase to extend over the entire surface of the substrate and effecting a fermentation phase wherein the fermentation product, citric acid is produced, and in the germination phase highly sterile air which has been pretreated through a coarse-fine-absolute filter, U-V sluice and superheated to about 120‹ C., is supplied in a small amount giving a slight excess pressure in the chamber whereby to prevent any extraneous infection from entering, and the fermenting substrate is independently heated by heaters, while in the exothermic fermentation phase the supply of highly sterile air and the heating are switched off and fresh, filtered unconditioned air is supplied to the chamber as cooling air so that the temperature of the fermenting substrate is kept substantially constant. The citric acid produced may be precipitated from solution as calcium citrate using milk of lime. Referring to the figure, the air conditioning system for use with germ-free chamber 2 consists essentially of an air system 4 for the germination phase including coarse filter 4-1, fan 4À2, fine filter 4À3, absolute filter 4À4, U-V sluice 4À5, superheater (to 120‹ C) 4À6 and valve 4À7, and a further air system 5 for the fermentation phase including coarse filter 5À1, fan 5À2, absolute filter 5À3 and valve 5À4. During the germination phase in which the fungus extends to cover the entire surface of the molasses substrate in the individual troughs 3, a small amount of highly sterile air is admitted from system 4 to produce an overpressure of from 5 mm. to 50 mm. water gauge in the chamber and the chamber is heated by heaters 6 fitted on each of the walls, and the cover and floor of the chamber. During the fermentation phase, in which the developed fungus exothermically ferments the molasses to produce citric acid, the chamber is supplied with sufficient fresh, filtered unconditioned air from system 5 to keep the temperature substantially constant, the air being vented through an exhaust valve 7. The air system 4 and heaters 6 are then not used.