The Growth Resources Enhancing Lipids for Bio-diesel Production in Chlamydomonas reinhardtii.

Abstract

The growth of the microalgae can be enhanced by optimizing the resources which will boost its growth rate and lipid yield. These resources include growth conditions and nutrient concentration and availability. This study sought to determine the effect of the growth resources of light, photoperiod, carbon dioxide and urea concentration and nitrogen limitation on growth rate and lipid production in Chlamydomonas reinhardtii. Screening and isolation of the alga was carried out from samples collected from the Nairobi Dam
and grown in Modified Bold’s Basal Media. Various isolates of algae were collected and C. reinhardtii was chosen as the candidate species. The results indicated an optimum growth at light intensity of 240 µmol m^-2 s^{-1 in an 18-hour photoperiod. The yield data on biomass of the alga grown at this photoperiod had a mean dry weight of 53.5±1.29g after a 3 week growth period while a 6-hour photoperiod recorded 25±1.09g translating to daily increase of 2.5g/day and 1.2g/day respectively. Chlamydomonas reinhardtii showed a tolerance response of 15% CO}₂ concentration and a robust growth in urea of 2.4g/l, giving lipid yield of 4.9ml/g of the dry weight. Growth in 1.2g/l of urea also gave a yield of 5ml/g of dry weight. The alga grown in 100gms of nitrogen gave a lipid yield of 0.592g of in contrast to 0.102g for those grown in 250gms.These results showed that by optimizing these growth resources a higher biomass density and lipid yield for bio-diesel production can be obtained from this alga.

Keywords: Chlamydomonas reinhardtii, lipids, growth resources.