Nannochloropsis sp. F&M‐M24: Oil production, effect of mixing on productivity and growth in an industrial wastewater

Abstract

The energy balance of microalgal biodiesel production is rarely considered. Besides, the actual potential of microalgae as triglyceride producers is often overestimated. This work was aimed at investigating these critical aspects using the marine eustigmatophyte Nannochloropsis sp. F&M‐M24, a promising oil producing strain, as model organism and the “Green Wall Panel” as culture system. First, the influence of air‐flow rate on volumetric productivity of the microalga was evaluated. At low and medium irradiances, no significant differences in productivity occurred at the three different mixing rates tested, while at high irradiances an increase in the air‐flow rate resulted in significantly higher volumetric productivities. These results allow to foresee a strategy of air‐flow rate tuning in accordance to radiation, that may lead to substantial energy savings and, consequently, to more favorable energy and economic balances in the cultivation process. Second, the lipid content and fraction distribution of the biomasses produced under nutrient sufficient and nitrogen‐starved conditions were analyzed and the neutral lipid fraction was fully characterized. Finally, the alga was grown in bubbled‐tubes using a culture medium prepared with an industrial wastewater, to evaluate its ability to use a free of charge source of nutrients, the exploitation of which may improve biomass production economics. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 846–853, 2013

Cultivation of Nannochloropsis for eicosapentaenoic acid production in wastewaters of pulp and paper industry

“…Nannochloropsis sp. F&M-M24 has earlier been shown to grow in a low-salt medium containing 50% industrial wastewater (Biondi et al, 2013), and an unnamed Nannochloropsis strain grew well in a 1:1 mixture of seawater and municipal wastewater, but in higher proportions of municipal wastewater, growth ceased after 2-3 days of cultivation (Jiang et al, 2011). In the raw DE, aluminum and manganese are the only elements whose concentrations are so high that they would be toxic to algae (Table 2).…”

Oil and eicosapentaenoic acid production by the diatom Phaeodactylum tricornutum cultivated outdoors in Green Wall Panel (GWP®) reactors

“…It is well known that under stress conditions, the so-called oleaginous microalgae can increase cellular lipid content, mainly the neutral lipid fraction, although the response is species-specific (Benvenuti et al, 2015;Piorreck et al, 1984;Pruvost et al, 2009;Rodolfi et al, 2009). Nitrogen limitation and starvation are the most frequently applied stresses for increasing lipid (oil) content, as this technique is cheap, easy to apply, and has a reliable and strong effect in oleaginous species (Benvenuti et al, 2015;Biondi et al, 2013;Bondioli et al, 2012;Converti et al, 2009;Guccione et al, 2014;Ho et al, 2012;Klok et al, 2013). However, nutrient deprivation decreases growth and may not necessarily improve lipid productivity (Griffith and Harrison, 2009).…”

Microalgae Cultivation on Anaerobic Digestate of Municipal Wastewater, Sewage Sludge and Agro-Waste

“…They are capable of both autotrophic and heterotrophic growth whenever a proper carbon source is supplied [22]. Nannochloropsis species are marine microalgae with high lipid productivity; indeed, Nannochloropsis gaditana can store up to 70% of its biomass in oleaginous form [12,23,24]. Nannochloropsis cells are non-motile and have a diameter varying from 2 to 8 µm.…”