Production of biodiesel from Spirogyra elongata, a common freshwater green algae with high oil content

Authors: SAEED, AASMA - University Of Agriculture - Pakistan; ASIF HANIF, MUHAMMAD - University Of Agriculture - Pakistan; HANIF, ASMA - Government College Women University Faisalabad; RASHID, UMER - Universiti Putra Malaysia; IQBAL, JAVED - University Of Agriculture - Pakistan; IRFAN MAJEED, MUHAMMAD - University Of Agriculture - Pakistan; Moser, Bryan; ALSALME, ALI - King Saud University

Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2021
Publication Date: 11/18/2021
Citation: Saeed, A., Asif Hanif, M., Hanif, A., Rashid, U., Iqbal, J., Irfan Majeed, M., Moser, B.R., Alsalme, A. 2021. Production of biodiesel from Spirogyra elongata, a common freshwater green algae with high oil content. Sustainability. 13(22). Article 12737. https://doi.org/10.3390/su132212737.
DOI: https://doi.org/10.3390/su132212737

Interpretive Summary: This research reveals that the oil from a common freshwater green algae is acceptable as an alternative, low-cost, non-food feedstock for production of renewable biodiesel as an alternative to conventional diesel fuel. The objective of this study was to produce biodiesel from oil extracted from the algae (Spirogyra elongata) and evaluate its fuel properties taking into consideration important American and European biodiesel fuel standards. Overall, the properties of biodiesel from the algal oil were comparable to that of soybean-based biodiesel, thus indicating its acceptability as a new source of biodiesel fuel. These results will be important to biodiesel producers, distributors, and end-users (customers) because a new biodiesel fuel was described that exhibits favorable fuel properties. This research may ultimately improve market penetration, availability, and public perception of renewable agricultural fuels such as biodiesel, thus affording greater national independence from petroleum-based fuels.

Technical Abstract: The need for exploring non-food low-cost sustainable sources for biodiesel production is ever increasing. Commercial and industrial algae cultivation has numerous uses in biodiesel production. This study explores S. elongata as a new algal feedstock for the production of biodiesel that does not compete with food production. The major fatty acids identified in S. elongata oil were oleic (30.5%), lauric (29.9%), myristic (17.0%), and palmitic (14.2%) acids. Transesterification to FAME was conducted using basic (KOH), acidic (HCl), and Zeolitic catalysts for assessment. The yields with acidic (54.6%) and zeolitic (72.7%) catalysts were unremarkable during initial screening. The highest biodiesel yield (99.9%) was achieved using KOH, which was obtained with the optimum reaction conditions of 1.0% catalyst, 60 °C, 4 h, and an oil-to-methanol volume ratio of 1:4. The yields with acidic (54.6%) and zeolitic (72.7%) catalysts were unremarkable during initial screening. The resulting S. elongata oil methyl esters exhibited densities, CNs, and IVs that were within the ranges specified in the American (ASTM D6751) and European (EN 14214) biodiesel standards, where applicable. In addition, the high SVs and moderately high CPs and PPs were attributed to the presence of large quantities of short-chain and saturated FAME, respectively. Overall, the composition and properties of FAME prepared from S. elongaae oil indicate that S. elongata is suitable as an alternative algal feedstock for the production of biodiesel.