Utilization of seawater for cost-effective cultivation and harvesting of Scenedesmus obliquus

Abstract

Microalgae hold great promise as a source of biofuels and biochemicals. The main obstacles to their industrial application are the high cultivation and downstream costs related to media and harvesting. In the work, we explored the multiple potentials of seawater to address key issues relating to the cultivation of Scenedesmus obliquus. Seawater can sufficiently replace some of the key elements in BG11 medium such as MgSO4, CaCl2, and NaCO3, and its use can significantly reduce the quantity of water required for the preparation of culture media. Among our results, the total chlorophyll content in cells grown in modified BG11 using 10 % (v/v) seawater was increased 1.47-fold without sacrificing biomass or lipid production. More than 70 % of the total algal biomass was auto-flocculated within one hour when cells were grown in seawater-supplemented media, which compares very favorably with a yield of only 3 % from cells grown in BG11.

Culturing Microalgae from Nature: Simple Experiment During Pandemic Covid-19

“…In seawater, the yellow-green colour is assumed that there is an indication of micro-algae growth by yellow-green algae (xanthophytes), which has chlorophyll E pigment [28]. Compared with freshwater, seawater contains more dissolved ions, the most abundant are sodium, chloride, magnesium, sulfate, and calcium, which are required for micro-algae to growth, including various minerals, such as nitrogen sources and phosphate sources [29].…”

“…Five bottles with different water sources were put under the sun for 2 weeks. The water sources used in this experiment were mineral water (130), tap water (84), puddle (89), river (89), pool (91), aquarium (23), groundwater (4), rainwater (29), lake (4), reservoir (8), well (53), rice field (6), spring water (4), and ocean (1).…”

Utilization of Microalgae in Aquaculture System: Biological Wastewater Treatment

“…Chlorella ellipsoidea (FBCC180008) and Scenedesmus dimorphus (FBCC110009), both acquired from the NNIBR (Nakdonggang National Institute of Biological Resources, Republic of Korea), were mixed in ten sets of cylindrical 10L plastic bottles for cultivation. SBG11 (10%-seawater-supplemented BG11) culture medium [33] with a constant 1%-CO2 (v/v)-enriched air flow (250 mL/min) at 28°C under continuous illumination at a light intensity of 100 µmol photons m -2 s -1 (LI-189 Li-Cor, PAR quantumsensor, Lincoln, USA) was used for strain maintenance. Preparatory to measurement of the microalgae's dry weight, the cells were filtered through filter paper (GF/C glass-fiber) and dried at a temperature of 60°C for 24 h, and subsequently, the filter paper's final weights were compared with the initial ones.…”

Lipid productivity in limnetic Chlorella is doubled by seawater added with anaerobically digested effluent from kitchen waste

“…The addition of 20% deep-sea water to the culture medium effectively enhanced the cell growth and oil accumulation of the algae. Jung et al [ 9 ] found retardation in cell growth when more than 10% seawater was added to BG11 medium for cultivation of Scenedesmus obliquus , and higher fatty acid yields relative to those in the standard BG11. Some reports added NaCl to the medium to build a salt-stress environment for hyperaccumulation of lipids in limnetic algae, and the results were satisfactory [ 10 ].…”

“…Besides the main nutrients, trace elements play an important role in rich algal growth, and are also costly. Fortunately, seawater contains abundant mineral elements supporting marine biology [ 9 ], which might also be used for freshwater algal activity. Therefore, cultivating freshwater microalgae with seawater has practical value and a good prospect for application.…”