Effect of the culture conditions on the growth and lipid contents of two strains of Nannochloris sp. to be used in aquaculture

Resumen

two strains of microalgae were obtained from the Texcoco lake, Mexico and San Pedrito Oasis Baja California Sur mexico, and named C1 and C2 respectively, previosly were selected as good candidates to improve the mass culture of a native strain of Brachionus plicatilis. In the laboratory, the isolates were purified and acclimated to growth under marine conditions at 35 ppt salinity and at 27-30ºC. Both strains were identified as Nannochloris sp. based primarily on their a, b chlorophyll and carotene contents and on light and transmission electron microscopy of the cell. Different culture conditions were tested in order to evaluate their effect on growth and lipid content. Differences in the response of both strains were found. Nannochloris sp strain C2 ws better adapted to different culture conditions (media, nitrogen concentrarion and culture vessel); this strain achieved higher growth and major lipid contents than strain C1. The conditions which improved the yield of both strains, are described. Also it was found that Nannochloris sp. strain C2 (isolated from a coastal oasis) has apparent advantages in yield over Nannochloris sp. strain C1 for use in aquaculture.