Heterotrophic cultivation of microalgae, scenedesmus dimorphus

• Main Author: Siong, Samantha Ling Chee
• Format: Final Year Project Report
• Language: English
• Published: Universiti Malaysia Sarawak, (UNIMAS) 2011
• Subjects: QR Microbiology; SH Aquaculture. Fisheries. Angling
• Online Access: http://ir.unimas.my/id/eprint/6423/8/Samantha%20Siong%20Ling%20Chee.pdf; http://ir.unimas.my/id/eprint/6423/
• Institution: Universiti Malaysia Sarawak

Heterotrophic growth of microalgae is an alternative method for biodiesel production. Microalga Scenedesmus sp. is one of the selective strains used as biomass feed source after Chlorella sp. due to its high lipid contents. So far, there is no study focus on the heterotrophic growth of Scenedesmus dimorphus. The aim of this study was to develop technique of heterotrophic cultivation of the microalga. Pre-isolated S. dimorphus was used as heterotrophic microalgae and maintained in Modified Bristol’s Medium (MBM) at room temperature (21-24oC) and then grew at different concentrations of organic nutrients such as glucose, fructose, acetic acid, and proteose peptone and pH. The growth of S. dimorphus under such conditions was investigated. Cell counting using Neubauer haemacytometer was used for growth measurement and neutral lipids was detected using Nile Red staining method. Results showed that S. dimorphus grew better in glucose at pH 5 condition with the highest growth rate reached 0.48. The highest growth rate of the microalga achieved in fructose, acetic acid, and proteose peptone, however were 0.35, 0.33, and 0.21, respectively. Glucose under illumination also supported a mixotrophic growth of S. dimorphus. Accumulation of neutral lipids in heterotrophic S. dimorphus cells was higher than that of the mixotrophic cells. Size of the microalgal cells and cell morphology had also been affected.