STEROL, FATTY ACID, AND PIGMENT CHARACTERISTICS OF UTEX 2341, A MARINE EUSTIGMATOPHYTE IDENTIFIED PREVIOUSLY AS <em>CHLORELLA MINUTISSIMA</em> (CHLOROPHYCEAE).

An examination of sterols of UTEX 2341, a small (ca. 2 μm), nonmotile unicellular marine alga identified as Cholerlla minutissima marina alga identified as Chlorella minutissma Fott et Novakova, yielded results inconsistent with any of 35 Chlorella strains analyzed previously. UTEX 2341 contained cholesterol as the principal sterol, with 24-methylenecholestrol, fucosterol, and isofucosterol also present; these are not dominant sterols in any other Chlorella species. Presence of eicosapentaenoic acid in UTEX 2341 also contrasted with fatty acids of Chlorella strains analyzed previously. Pigment analysis of UTEX 2341 revealed that it contained chlorophyll a, but not chloropyylls b or c; violaxanthin was the only major xanthophylls pigment. Both lipid and pigment compositions suggest that UTEX 2341 is not a member of the genus Chlorella but, rather, belongs in the Eustigmatophyceae; it may be Nannochloropsis sp. Cells with possible extracellular structures were present at an appreciable percentage of the stationary-phase population studied; centrifuging removed or collapsed these structures. The high cholestrol and polyunsalturated fatty acid contents of UTEX 2341 make it attractive as a potential aquaculture feed, provided it is, or can be made, digestive. [ABSTRACT FROM AUTHOR]