Patent ID: 7091013
Filing Date: 2006-08-15
Classification: C12N,C12P,C12R

Abstract:
1. A process for producing sodium 2-keto-L-gulonate by fermentation and recovering 2-keto-L-gulonic acid monohydrate crystals, said process comprising: a) fermenting sorbitol in a fermenting medium in the presence of micro-organisms for converting sorbitol into at least 50 g/L sodium 2-keto-L-gulonate, b) removing the microorganisms from the fermentation medium thereby obtaining a microorganism-reduced fermentation broth, c) converting sodium 2-keto-L-gulonate into 2-keto-L-gulonic acid in the microorganism-reduced fermentation broth, and removing proteins to a concentration below 2400 ppm measured as nitrogen on dry substance to obtain a purified fermentation broth and adjusting the pH of the purified fermentation broth to a pH above 1.5 for avoiding the formation of vitamin C in a concentration higher than 3% based on dry substance, during the subsequent evaporation of water, d) evaporating water from the purified fermentation broth to obtain a concentrated purified fermentation broth, and e) recovering 2-keto-L-gulonic acid monohydrate crystals by crystallization from the concentrated purified fermentation broth with a recovery yield for 2-keto-L-gulonic acid of 80% or higher.