Evaluating the usability of 19 effluents for heterotrophic cultivation of microalgal consortia as biodiesel feedstock

Authors: JORDAAN, ERIKA - Tshwane University; ROUX-VAN DER MERWE, RENATE - Tshwane University; BADENHORST, JACKIE - Tshwane University; Knothe, Gerhard; BOTHA, BEN - Tshwane University

Submitted to: Journal of Applied Phycology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2017
Publication Date: 11/27/2017
Citation: Jordaan, E., Roux-van der Merwe, M.P., Badenhorst, J., Knothe, G., Botha, B.M. 2018. Evaluating the usability of 19 effluents for heterotrophic cultivation of microalgal consortia as biodiesel feedstock. Journal of Applied Phycology. 30(3):1533-1547. doi: 10.1007/s10811-017-1341-x.
DOI: https://doi.org/10.1007/s10811-017-1341-x

Interpretive Summary: This research determined that algal oils are suitable as biodiesel feedstock. Biodiesel can be produced from various oils such as vegetable, animal fats, and used cooking oils and greases. In order to expand the available biodiesel feedstocks economically, alternative oils from algae were explored. This work reports potential biodiesel feedstock oils produced by algae which was grown with the aid of inexpensive industrial effluents. The different effluents have different effects on algae growth while oil production in the algae depends more on the type of algae. These findings are important because discovering high yielding alternative biodiesel feedstocks could produce more revenue for the biobased economy as well as produce a superior biodiesel product for the fuel market.

Technical Abstract: A key reason inhibiting commercialization of algal oil as biodiesel feedstock is cultivation cost. For this reason, the usability of 19 readily available industrial effluents (autoclaved and non-autoclaved) to support heterotrophic growth and lipid accumulation was evaluated using six mixed algal cultures. Autoclaved whey effluent was the best with 14.32 g biomass/L, 13.23% lipids, resulting in a lipid production of 1.91 g lipids/L. Biomass production and lipid accumulation were in many cases inverse, e.g. mixed algal culture termed TUT4 accumulating 84.25% lipids on autoclaved acid mine drainage, with very little biomass produced. Biomass production was dependent on the effluent type, whereas the lipid accumulation was influenced mostly by the specific mixed algal cultures. The fatty acid composition of the algal oil (fish cannery and whey effluents) showed high saturation, leading to acceptable cetane numbers, kinematic viscosity, good oxidative stability, but poor cold flow properties.