Cultural optimization of thraustochytrids for biomass and fatty acid production

[摘要] Two thraustochytrids isolated from fallen mangrove leaves in Subic Bay, Philippines were identified based on their cell morphology, sporogenesis and spore release as: Thraustochytrium sp. SB04; and Schizochytrium sp. SB11. Physiological screening (temperature, seawater concentration, glucose concentration and initial pH) was undertaken on the two isolates for optimization of culture conditions for biomass and total fatty acid production. Both isolates survived and grew well on glucose as their sole source of carbon. Highest biomass production for the two isolates were obtained at lower glucose concentrations (3–5% w/v) in a half-strength natural seawater (50–60% v/v), at near neutral pH (6.0), and incubation temperatures of 20–30°C. Growth curve analysis showed slower growth (1 d lag time) and a shorter stationary phase (less than 1 day) for Thraustochytrium sp. compared to Schizochytrium sp. Additional extracellular enzyme screening showed that both isolates only produced lipase. Analysis of fatty acid methyl ester results showed that Thraustochytrium sp. produced predominantly short chain fatty acids with oleic acid (18:1), a monounsaturated fatty acid (MUFA) making up as much as 71% of the total fatty acids (TFA). Schizochytrium sp., on the other hand, produced high amount of docosahexaenoic acid (DHA) and comprised up to 22.5% of TFA. The large amount of MUFA makes this Thraustochytrium sp. a viable source of oil for biodiesel production. Just as important is the high amount of DHA produced by Schizochytrium sp., a potential source for local large-scale DHA production.

[学科分类] 植物学

[关键词] thraustochytrid/s;MUFA;PUFA;culture optimization;biomass production;fatty acid production