Menaquinones (MK-n) can be produced by the fermentation of Flavobacterium meningosepticum. This article deals with the process of extraction, purification and identification of MK-4, MK-5 and MK-6. Among the organic solvents tested, the maximum extraction yields (99.1%) were obtained using three successive 20-min methanol extractions. Purification and separation of the menaquinone homologs, extracted from dry microbial cells with methanol, was achieved using adsorption chromatography, gel permeation chromatography and reverse-phase C18 chromatography on columns with large processing capacities (0.95-7.0 mg menaquinones per packing gram). The purities of MK-5 and MK-6 crystals reached 96.3% and 99.2%, respectively, as calculated by the external standard method. High recovery rates of 94.7% (not crystallized), 87.3% and 88.2% of MK-4, MK-5 and MK-6, respectively, were achieved for the overall process from extraction to crystallization. Throughout the entire process, the only organic solvents used were methanol and dichloromethane, facilitating the recycling of these solvents and, hence, application of the method on a large scale. The vitamin K-2 homologs were identified as MK-4, MK-5 and MK-6 by MS, IR and H-1 NMR.