Effect of culture medium and nutrient concentration on fatty acid content of Chaetoceros muelleri

Resumen

Fatty acid content in microalgae can be modified by culture conditions. The purpose of this study was to determine the effect of nitrogen sources and their concentration in the polyunsaturated fatty acid (PUFAs) contents of cultured Chaetoceros muelleri. Chaetoceros muelleri was batch cultured at 19°C and a continuous light intensity of 150 mmol m-2s-1. Three different concentrations of culture medium (f, f/2 and f/4) were used. The experimental medium was prepared with liquid agricultural fertilizers (AF) in three concentrations (AF, AF/2 and AF/4). Chaetoceros muelleri was harvested at lag phase. Extraction of fatty acids was performed by direct transesterification and quantified by gas chromatography. The highest HUFA percentage was obtained with f/2 medium (8.65%), while the lowest was obtained with AF/2 medium (5.78%). A direct relationship between HUFA concentration and nutrient concentration in both culture media was found. It is concluded that C. muelleri must be cultured with f/2 medium or its equivalent AF/2 in an effort to obtain the highest HUFAs content. Additionally, the use of AF/2 medium results in a more cost effective option.