| 摘要 |
The invention relates to a process for obtaining a pectolytic enzyme preparation using a mutant strain of the species Aspergillus niger which is used for obtaining juice from vegetable and fruit broths and in the clarification of fruit and vegetable juices. The object is achieved by fermentation of a culture of Aspergillus niger. The mutant strain Asp. niger 8MX-41, which was registered on 28.2.1984 under No. 8 at the DIKLS in Sofia (National Institute for the Monitoring of Medicines), was used. The strain behaves differently on different nutrient media. Aspergillus niger 8MX-41 on malt agar forms, after about 72 hours, round colonies with a smooth margin, depressed centre and dense radial creases. After 7 days and nights have elapsed, the diameter of the colony reaches 9 cm and is black in colour. The fermentation liquid contains dried beet pulp, wheatbran, ammonium sulphate, sodium phosphate, starch, magnesium sulphate and potassium chloride. After fermentation for about 144 hours, the culture accumulates polygalacturonase and pectinesterase activity. After separation of the mycelium, the fermentation liquid is filtered to eliminate mechanical admixtures and then dried in vacuo or by lyophilisation. The fermentation takes place in a fermenter with aeration using sterile air. The input is 0.8 to 1.1 l per litre of fermentation liquid per minute.
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