Abstract: Animal-free meninge fermentation media and process is developed based upon use of a chemically defined medium. To improve polysaccharide production, fed-batch fermentation is examined using different feed solutions and feeding strategies. A feed solution containing glucose, amino acids, and trace metal elements produces Group A polysaccharide at approximately 3 times the level observed with batch fermentation. This process is used successfully to produce polysaccharides of N. meningitidis serotypes, A, C, Y and W-135 and is run reproducibly at the 20 L scale and can be scaled to 400 L or more.