THE ABSENCE OF LONG-CHAIN ALKYL DIOLS AND ALKYL KETO-1-OLS IN CULTURES OF THE CYANOBACTERIUM APHANIZOMENON-FLOS-AQUAE

Batches of the cyanobacterium Aphanizomenon flos-aquae were cultured using different growth conditions to search for long-chain alkan-1,15-diols and alkan-15-one-1-ols expected to occur in these organisms based on a field sample study (Morris and Brassell, 1988). These compounds which are ubiquitous in Recent sediments were not present either free or bound in any of the cultures analysed, indicating that results of chemotaxonomical studies based on field samples should be interpreted with great caution. This statement is further supported by the absence of sterols in the cultured algae and their relatively high abundance in the field sample. A specific lipid, tentatively identified as (omega - 1)-hydroxyhexacosanoic acid, was encountered in the cultured alga and has potential as a biomarker.