Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities

doi:10.1016/j.jbiosc.2016.09.015

Journal of Bioscience and Bioengineering

Volume 123, Issue 3, March 2017, Pages 314-318

https://doi.org/10.1016/j.jbiosc.2016.09.015 Get rights and content

Microalgae have been accepted as a promising feedstock for biodiesel production owing to their capability of converting solar energy into lipids through photosynthesis. However, the high capital and operating costs, and high energy consumption, are hampering commercialization of microalgal biodiesel. In this study, the surface-floating microalga, strain AVFF007 (tentatively identified as Botryosphaerella sudetica), which naturally forms a biofilm on surfaces, was characterized for use in biodiesel production. The biofilm could be conveniently harvested from the surface of the water by adsorbing onto a polyethylene film. The lipid productivity of strain AVFF007 was 46.3 mg/L/day, allowing direct comparison to lipid productivities of other microalgal species. The moisture content of the surface-floating biomass was 86.0 ± 1.2%, which was much lower than that of the biomass harvested using centrifugation. These results reveal the potential of this surface-floating microalgal species as a biodiesel producer, employing a novel biomass harvesting and dewatering strategy.

Section snippets

Strain and growth conditions

A green microalga species (termed strain AVFF007) found floating naturally on a water surface, was isolated from a freshwater pond in Kyoto, Japan. Strain AVFF007 was maintained in CSi medium (17) under continuous illumination using cool white fluorescent lights. To obtain the floating biomass, the strain AVFF007 was statically inoculated into 40 mL volume plastic cases (size: W50 × D63 × H25 mm, AS ONE, Osaka, Japan) in a desiccator (AS ONE), at an initial cell density of 1 × 10⁵ cells/mL.

Characterization of strain AVFF007

Fig. 1 shows a typical static culture of strain AVFF007 in a glass flask. Most of the cells floated naturally upon the surface of the medium during static cultivation, while a portion of cells settled to the bottom of the medium. The floating cells formed biofilm, the surface of which was completely dry. Static cultivation was essential for the flotation ability of the cells to result in biofilm formation, since biofilms were not observed under well-mixed culture conditions with continuous

Discussion

This study evaluated the feasibility of biodiesel production by a water surface-floating microalga, strain AVFF007, which was tentatively identified as B. sudetica. B. sudetica (UTEX2629) has recently been proposed to be a potentially useful strain for microalgal biomass production (26). However, its ability to float at the surface of water and its possible use for biodiesel production have not been reported. Comparisons between the biomass yields and lipid productivities of strain AVFF007 and

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Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities

Section snippets

Strain and growth conditions

Characterization of strain AVFF007

Discussion

Appl. Energy

Biotechnol. Adv.

Bioresour. Technol.

Bioresour. Technol.

Trends Biotechnol.

Biomass Bioenergy

Bioresour. Technol.

J. Biol. Chem.

Fuel Process. Technol.

Algal Res.

Combinatorial life cycle assessment to inform process design of industrial production of algal biodiesel

Environ. Sci. Technol.

Benchmark study on algae harvesting with backwashable submerged flat panel membranes

Bioresour. Technol.

Harvesting of microalgae Scenedesmus sp. using polyvinylidene fluoride microfiltration membrane

Desalination Water Treat.

Evaluation of an inclined gravity settler for microalgae harvesting

J. Chem. Technol. Biotechnol.

Harvesting of microalgae Dunaliella salina using electroflocculation

J. Agric. Sci. Technol.