Master of Science (MS)
School of Nutrition and Food Sciences
Four microalgae, obtained from different brackish and fresh water sources within the state of Louisiana’s Southeast region, were evaluated for their potential use in the production of biodiesel. The microorganisms were isolated and identified using genomic DNA, and 16S rRNA or 18S rRNA gene amplification followed by sequencing. The resultant sequences were compared with those available on the NCBI website database through the BLAST bioinformatic tool. The results showed high correlation with known nucleotide sequence identities at 99 % with Synechococcus sp., 98 % with Sellaphora pupula, 99 % with Chlorella sorokiniana, 99 % with Scenedesmus abundans, and 99 % with Chlorella vulgaris (control). The fatty acid profiles of the identified organisms grown using 5 % CO2 aeration into the growth media were evaluated and were found to be different to the control group (0.037 % CO2). In Synechococcus sp., total fatty acids (TFA) decreased from 20.63 g kg-1 to 17.62 g kg-1 dry biomass with the appearance of C18:2 and C18:3, which were absent in the control. TFA from Sellaphora pupula decreased from 54.8 g kg-1 to 24.4 g kg-1 dry biomass and contained the greatest C16:1. The extracted TFA from Scenedesmus abundans increased from 14.14 g kg-1 to 31.63 g kg-1 and displayed the highest content of C18:1. For Chlorella vulgaris UTEX 259, TFA content increased from 15.14 g kg-1 to 47.83 g kg-1, and 50 % of that total was C18:3. The TFA content from Chlorella sorokiniana decreased from 29.82 g kg-1 to 23.99 g kg-1; however, it had a lower C18:3 which allowed for a balanced fatty acid profile in terms of cetane number, oxidative stability, viscosity and low temperature conditions. The aforementioned conditions, plus owning the best biomass productivity when using 5 % CO2, deemed Chlorella sorokiniana as the best candidate of the strains evaluated for the production of biodiesel.
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Moreno, Reynaldo, "Identification of algal strains by PCR amplification and evaluation of their fatty acid profiles for biodiesel production" (2012). LSU Master's Theses. 2479.