Parametric Study on Mixotrophic Cultivation of Chlorella vulgaris Beijerinck for Biodiesel Production

Author : Ofrasio, Bjorn Ivan Gonzales
Major Adviser : Demafelis, Rex B.
Major Co-Adviser : June Owen O. Nacorda
Committee Members : Dizon, Lisa Stephanie H.; Borines, Myra G.
Year : 2015
Month : July
Type : Thesis
Degree: BS
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Chlorella vulgaris CV1 strain isolate from Laguna de Bay were investigated for biomass productivity by mixotrophic cultivation by manipulating four variables: illumination patterns (natural or artificial light cycle), carbon source (glucose or glycerol), carbon source concentration (0.5 or 10 g·L-1) and nitrogen source (urea) concentration (0.02073 or 0.04146 g·L-1) in 100-mL cultures. Using cell dry weight method, it was found out that the largest biomass productivity was obtained from the microalgal culture treated with 10 g·L-1 glycerol, 0.04146 g·L-1 urea and under controlled light. Furthermore, it was observed that there is a significant difference in the biomass productivities at different carbon sources (favoring glycerol) while no difference were observed at different carbon concentrations, urea concentrations and illumination patterns. The cultivation conditions at best biomass productivities were cultivated in two 4-L cultures for biomass harvesting and oil extraction. The oil yield and lipid productivity was found to be 3.50% and 7.5042 mg·L-1·day-1. The lipid obtained was found to contain 46.19% triacylglycerol (TAG), 47.26% free-fatty acids (FFA) and 6.555% diacylglycerols (DAG). The high FFA content has made the Chlorella vulgaris oil unsuited for transesterification process.

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