Overall development of a bioprocess for the outdoor production of Nannochloropsis gaditana for aquaculture

Abstract

In this paper, a systematic methodology is shown for the scaling-up of Nannochloropsis gaditana production for aquaculture uses. First, an adequate culture medium was developed, prepared using fertilizers instead of pure chemicals. Subsequently, the performance of N. gaditana was modelled as a function of average irradiance; this model being validated in continuous culture experiments. The model was used to determine the optimal dilution rate as well as the expected biomass concentration and productivity at optimal conditions. Finally, outdoor experiments were performed to confirm the model's validity and to determine optimal conditions at real production step. | INTRODUCTIONMicroalgae are unicellular organisms that vary in size and shape.They exist in almost all known habitats. Due to their unique biochemical composition, microalgae are exploited for a variety of applications ranging from pharmaceuticals and nutraceuticals to human food and feed, especially for aquaculture (Spolaore, Joannis-Cassan, Duran, & Isambert, 2006). Traditionally, microalgae production in aquaculture represents one of the main problems in the development of a number of processes; this is due to the typically low productivity and poor quality of the resulting biomass along with contamination and high production costs (Muller-Feuga, 2000).Moreover, replacement of fish meal and fish oil by microalgae biomass has been largely reclaimed as alternative to actual sources that are reaching its maximal production capacity, whereas aquaculture demand continuously increase (Lem, Bjorndal & Lappo, 2014). However, the inclusion of microalgae in aquafeed for fish or crustaceans is still at early stage of development, mainly because the availability of, cheap but with enough quality, microalgae biomass is low and optimal strategies to include it into aquafeed is not fully developed.Different species of microalgae have been tested in fish and crustacean aquafeed, mainly for enhancement of immune system rather than as alternative to conventional raw materials (Canavate, 2017).Whatever the final application, industrial microalgae production Regarding the production system, to carry out microalgae production on a large scale it is essential to select the most suitable photobioreactor type. For this, different parameters must be considered depending on the microorganism selected, such as (1) its optimal growth conditions and resistance to variations in environmental conditions, and (2) In this work, we have developed a process for the outdoor production of microalgae as feed for aquaculture. First, we selected the strain and culture medium, optimized using mineral salts instead of pure chemicals. Following this, we optimized the productivity in continuous culture experiments, and modelled the influence of light availability on the growth rate as a prior step to scaling-up the production to outdoor conditions. Finally, the real outdoor photobioreactor performance was validated, evaluating the composition of the produced biomass and its suitabilit...

Growth and Nitrate Uptake in Nannochloropsis gaditana and Tetraselmis chuii Cultures Grown in Sequential Batch Reactors

“…Under nitrogen starvation conditions, N. gaditana is known to accumulate lipids in the order of 40-60% (w/w) (Fabregas et al, 2002;Rocha et al, 2003;Benito et al, 2015;Fernandes et al, 2016) in the form of triacylglycerol and polyunsaturated fatty acids (PUFA) (Ma et al, 2016). The current market-relevant production of Nannochloropsis strains is mainly as food supplements for Eicosapentaenoic Acid (EPA), as aquaculture feed in the form of concentrates and pastes, and in skin care products (Enzing et al, 2014;Riveros et al, 2018). Reported growth rate values for N. gaditana are outlined ( Table 2).…”

Nutritional Enhancement of Farmed Salmon Meat via Non-GMO Nannochloropsis Gaditana: Eicosapentaenoic Acid (EPA, 20:5 n-3), Docosapentaenoic Acid (DPA, 22:5 n-3) and Vitamin D3 for Human Health

“…Nannochloropsis gaditana strain (Lubián CCMP 527) was maintained under controlled conditions at 20 °C, in 250 mL flasks, with constant aeration at 0.1 v / v /min with no CO 2 supply, under constant illumination at 200 µE m −2 s −1 provided by fluorescent lamps, in “UMA 5” culture medium prepared from fertilizers instead of pure chemicals [ 47 ]. The culture medium was prepared using natural seawater and nutrients of analytical grade, and was autoclaved for 15 min.…”

“…Cultures were hatched at 20 °C. A UMA 5 culture medium was used (NaNO 3 : 0.4 g/L, NaH 2 PO 4 : 0.034 g/L, NaHCO 3 : 0.168 g/L and trace elements µmol/L, Zn 0.08, Mn 0.90, Mo 0.030, Co 0.050 and Fe 11.70) [ 47 ]. The culture was initiated in a semi-continuous mode, in which 75% of the culture medium and vitamin supplementation (thiamine, biotin, and cyanocobalamin) were deprived.…”

The effect of heavy metals on the viability of Tetraselmis marina AC16-MESO and an evaluation of the potential use of this microalga in bioremediation

“…Tetraselmis was isolated from the intertidal area of the San Jorge Bay, Antofagasta, specifically from the area known as the Beach of the Oil Companies (”Playa de las Petroleras”), and identified and preserved at the University of Antofagasta marine mesocosm facility (Mata et al in press). Algae were grown in Erlenmeyer flasks of 2 liters until reaching sufficient biomass for analysis, in UMA5 medium ( Riveros et al, 2018 ) (NaNO 3 4.55*10 −5 M; NaH 2 PO 4 *H 2 O 2.41*10 −4 M; NaHCO 3 1.99*10 −3 M) at 20 °C and a continuous photosynthetic photon flux of 70 µmol m −2 s −1 (24 h light).…”