Growth characteristics and toxin production in batch cultures of Anabaena flos-aquae: effects of culture media and duration

The effects of media and culture duration on growth, macromolecular composition and toxicity of an anatoxin- a-producing freshwater cyanobacterium Anabaena flos-aquae (UTEX 2383) were evaluated. The four media A3M7, CB, MA and B-12 influenced growth in terms of cell number, chlorophyll-a content and specific growth rate. A3M7 medium supported the best growth. The macromolecular composition of cultured cells, viz. total carbohydrate, protein and lipid content varied with media and culture duration reaching maximum concentration at various growth periods. The differences were significant due to interaction of the culture medium and duration. Toxicity of cells grown in different media was compared by Artemia salina bioassay and mouse units. The cells grown in A3M7 medium showed highest toxicity and the optimum culture duration was 5 weeks. In terms of both growth characteristics and toxicity the media can be ranked as A3M7, MA, CB and B-12 in decreasing order.