Continuous culture methodology for the screening of microalgae for oil

摘要

A basic criterion in the selection of microalgae suitable as source of oil for biodiesel\udshould be their actual capacity to produce lipids or, more properly, the fatty acid yield.\udPerformance assessment of ten preselected microalgae under both batch and continuous\udculture points to the latter approach as the most adequate for evaluating fatty acid\udproductivity. Differences were patent in continuous culture among strains that otherwise\udhad analogous oil accumulation potential under batch culture. Some promising strains\udunder batch culture (like Muriella aurantiaca and Monoraphidium braunii) exhibited,\udhowever, values for actual fatty acid productivity lower than 40 mg L-1d-1 in continuous\udregime. The analysis performed in photochemostat under continuous culture regime\udrevealed the great potential of Chlorococcum olefaciens, Pseudokirchneriella\udsubcapitata and Scenedesmus almeriensis as oil producing microalgae. Fatty acid\udproductivity levels over 90 mg L-1d-1 were recorded for the latter strains under moderate\udnitrogen limitation, conditions which led to an enrichment in saturated and\udmonounsaturated fatty acids, a more suitable profile as raw material for biodiesel. The\udcontinuous culture methodology employed represents a sound procedure for screening\udmicroalgae for biofuel production, providing a reliable evaluation of their fatty acid\udproduction capacity, under conditions close to those of outdoor production systems