Enhanced growth and lipid accumulation by a new Ettlia texensis isolate under optimized photoheterotrophic condition

A green microalgae, named as Ettlia texensis was obtained from local freshwater in Turkey. The effects of autotrophic, photoheterotrophic and heterotrophic cultivations on biomass and lipid production were studied. Searching the preferences of the carbon and nitrogen source revealed that this strain could grow photoheterotrophically well with glucose and yeast extract. In the optimized medium, the highest biomass productivity and total lipid content achieved were 0.97 g/L d and 26% of dry weight basis, respectively. Moreover, the major fatty acid methyl esters were C16:0; C18:1; C18:2 and C18:3. In a scale-up attempt, productions were accomplished in a 3 L stirred tank bioreactor. The final biomass and lipid productivities obtained in bioreactor with 250 rpm agitation rate were 0.92 g/L d and 322 mg/L d, respectively. The biochemical compositions were monitored simultaneously by the FTIR spectroscopy during the production in bioreactor. E. texensis could be potent candidate for commercial production in the bioreactor photoheterotrophically.