TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The step (f) is performed such that, The main steam is not supplied in the step (d) in normal operation, or 1-10 tons main steam per ton of product carboxylic acid, preferably 1.5-4 tons main steam per ton of product carboxylic acid is supplied. A permeate produced from the reverse osmosis is used as an eluent in the step (b). The step (a) is carried out by a pre-coat, a microfiltration and/or ultrafiltration, and the separated biomass is recycled back into the fermenter in the step (a). The step (a) is carried out without lowering the pH, and without thermal inactivation. The time between the end of the fermentation and the separation of the biomass is less, preferably not greater than 2 hours, preferably less than 1-2 hours. The biomass concentration in the filtrate is not more than 1 g/l in the step (a). The permeate is acidified with concentrated sulfuric acid to a pH of 2.2-2.4, where the temperature of the acidified permeate is maintained at 30-60 degrees C, preferably 30-40 degrees C. The addition of permeate in the step (b) from the filtration step and an eluent is carried out continuously in a ratio of permeate to eluent of 1:1.5-1: 2.5. The carboxylic acid is bound to a stationary phase of simulated moving bed chromatography, which has a cation exchanger and/or an anion exchanger. The extract comprises the carboxylic acid, dicarboxylic acid having a content of d 1 g / l, and the raffinate is collected separately from each further . The efficiency of the recovery of carboxylic acid from permeate of the filtration process is greater than or equal to 95%. The extract from the SMB chromatography is subjected to nanofiltration, where the membranes have a separation limit of 100-400 Da, preferably 200 Da, and/or a fine cleaning is carried out by activated carbon filtration, cation exchangers and/or anion exchanger. Preferred Components: The separated and purified carboxylic acids are hydroxycarboxylic acids and dicarboxylic acids, preferably malic acid, glycolic acid, isocitric acid, mandelic acid, lactic acid, tartronic acid, tartaric acid, citric acid, beta -hydroxybutyric acid, mevalonic acid, salicylic acid, oxalic acid, maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, fumaric acid and itaconic acid. EXAMPLE - No suitable example given.