Table 1 Summary of research on the rheology of slurries of microalgal cells

Wileman et al. [11],

1. Chlorella vulgaris,

2. Nannochloropsis sp.

0.05–8%

–

The slurries were Newtonian fluids up to 2% solids above which they showed shear thinning behaviour.

Adesanya et al. [8],

1. Scenedesmus obliquus

–

6.8–15%

The complex viscosity increased non-linearly with volume fraction; attributed to the deformable nature and mutual interaction between the cells in the suspension.

Zhang et al. [12],

1. Fresh water and marine Chlorella sp.

–

0.7–4.3%

The high-shear viscosities were low, around 2 times the viscosity of water.

Bernaerts et al. [9],

1. Chlorella vulgaris,

2. Porphyridium cruentum,

3. Odontella aurita

8%

–

All the suspensions were shear thinning weak elastic gels.

Cagney et al. [10],

1. Tetraselmis chuii,

2. Chlorella sp.

3. Phaeodactylum tricornutum,

–

5–20%

The cell suspension viscosity increased with the volume fraction.

Wu and Shi [15],

1. Chlorella pyrenoidosa

2.5–25%

–

The apparent viscosity of the cell suspension was rather low showing Newtonian behaviour until 15% solids above which the viscosity increased significantly (~ 1700 mPa.s at 25% solids) showing shear thinning behaviour.

Schnieder and Gerber [14]

1. Nannochloropsis salina

10–24%

–

The suspensions were shear thinning

Chen et al. [13],

1. Chlorella pyrenoidosa

10–20%

–

The apparent high-shear viscosity of a 20% solids suspension was around 40 mPa.s.

Yap et al. [16],

1. Nannochloropsis sp.

25%

–

The presence of chitosan resulted in a floc structure that was broken by shear, hence the rheology was significantly affected by pre-shear history of the suspension.