Isolation of a euryhaline microalgal strain, Tetraselmis sp. CTP4, as a robust feedstock for biodiesel production

Abstract

Bioprospecting for novel microalgal strains is key to improving the feasibility of microalgae-derived biodiesel production. Tetraselmis sp. CTP4 (Chlorophyta, Chlorodendrophyceae) was isolated using fluorescence activated cell sorting (FACS) in order to screen novel lipid-rich microalgae. CTP4 is a robust, euryhaline strain able to grow in seawater growth medium as well as in non-sterile urban wastewater. Because of its large cell size (9–22 μm), CTP4 settles down after a six-hour sedimentation step. This leads to a medium removal efficiency of 80%, allowing a significant decrease of biomass dewatering costs. Using a two-stage system, a 3-fold increase in lipid content (up to 33% of DW) and a 2-fold enhancement in lipid productivity (up to 52.1 mg L−1 d−1) were observed upon exposure to nutrient depletion for 7 days. The biodiesel synthesized from the lipids of CTP4 contained high levels of oleic acid (25.67% of total fatty acids content) and minor amounts of polyunsaturated fatty acids with ≥4 double bonds (<1%). As a result, this biofuel complies with most of the European (EN14214) and American (ASTM D6751) specifications, which commonly used microalgal feedstocks are usually unable to meet. In conclusion, Tetraselmis sp. CTP4 displays promising features as feedstock with lower downstream processing costs for biomass dewatering and biodiesel refining.

Growth performance, biochemical composition and sedimentation velocity of Tetraselmis sp. CTP4 under different salinities using low-cost lab- and pilot-scale systems

“…Tetraselmis sp. CTP4 was isolated from Ria Formosa (Portugal), as described in Pereira et al. (2016).…”

“…Microalgae are microscopic photosynthetic microorganisms currently regarded as a promising feedstock for several biotechnological applications such as biofuels, bioremediation, human and animal nutrition, as well as a source of high value compounds (Huerlimann et al., 2010; Sing et al., 2014; Pereira et al., 2016). Although recent reports suggested their wide biotechnological potential, the current production costs of microalgal biomass are still the main hindrance for large-scale commercialization.…”

“…In addition, Tetraselmis sp. CTP4 has previously been reported as a euryhaline, fast growing and robust microalgal strain, which holds high potential for scale-up in industrial production facilities (Pereira et al., 2018) as well as high sedimentation rates (Pereira et al., 2016).…”

Pelagibaca bermudensis promotes biofuel competence of Tetraselmis striata in a broad range of abiotic stressors: dynamics of quorum-sensing precursors and strategic improvement in lipid productivity

“…The strategic stress induced for the 3 days could not be optimum, but the results of this study support the usefulness of the two-stage cultivation model for T. striata under both T and T-PB conditions using nitrate limitation. The optimum stress induced by the elevated salinity/temperature/nutrient limitation mediated biochemical macromolecular synthesis, which would modulate metabolism to induce the levels of carbohydrate or lipid accumulation in Tetraselmis ; however, the response varies within genera/species [ 10 , 18 , 19 , 47 ]. Optimum stress conditions in two-stage cultivation for the amelioration of lipid productivity have been previously demonstrated in Tetraselmis , Scenedesmus , Acutodesmus , Nannochloropsis , Chlorella , Synechococcus, and Monoraphidium and Chlamydomonas [ 9 , 19 , 53 – 57 ] where the type, time, and intensity of the stress matter.…”

“…Some of the different microalgal seawater strains are accorded a relatively higher significance for open/semi-enclosed cultivation in coastal waters. Tetraselmis is well known for its commercial potential for biomass and biofuel production in coastal areas [ 18 , 19 ]. Tetraselmis spp.…”