Effect of exposure to the different concentration of pure CO2 gas on growth rates and fatty acids metabolism of green Alga Chlorococcum humicola

Abstract

The current study examined the effects of the exposure to the different concentrations of thepure CO2 on the growth rates and fatty acids metabolism of the green algae Chlorococcumhumicola that isolated locally. The algae cells exposure into many concentrations of CO2 (25,50, 75, 100%) v/v of culture media which were (BG11, Chu13, Chu10) for growing. Theexperiments were conducted in standard laboratory conditions such as temperature, lightingintensity, pH which were respectively (25±2°C, 3000 lux, 7.6) with lighting system 18:16 hour(light :dark). The supplementing of CO2 every 73 hour by the device (Gas-flow-meter). Theresults were recorded daily for 18 days. The results have shown that present responses in thegrowth rates of studied algal cells by all using cultures media that included in this study forgrowing the algae with best result in Chu13 media. As well as, the present study found that manytypes of fatty acids in dry biomass of algal cells in vitro by using HPLC technique and recordedthe following fatty acids: Myristic C14:0, Palmetic C16:0, Plamitolic C16:1, Arachidic C20:4,Linoleic C18: 2 (Omega:6), Oleic C18:1(Omega 9). The response value was changed betweenthe acids depending on the type of culture media and the following fatty acid: Palmetic C16:09,Myristic C14:0, Palmitolic C16:1, Olic C18:1 and Linolic C18:2) recorded the values (440.64, 474.54, 987, 770, 1054.25, 455.64) mg/L dry weight respectively in two concentrations (100,75%) v/v when growing the algae in the culture media Chu1. While the acid Arachidic C20:4recorded highest value (684.35) mg/L in the culture media BG11 at 100% concentration