Flocculation of Nannochloropsis oculata induced by sodium hydroxide: flocculation efficiency, viability effect on microalgae and their use as food for rotifers

Angel Humberto Rojo Cebreros, Manuel Eduardo Morales-Plascencia, Leonardo Ibarra-Castro, Juan Manuel Martínez-Brown, María Alejandra Medina-Jasso


DOI: https://doi.org/10.3856/vol44-issue4-fulltext-1

Aquaculture laboratories highly dependent of Nannochloropsis oculata develop mechanisms for mass production, with the challenge of be able to extract high cell concentrations from the culture medium. Flocculation by alkaline agents is an alternative that promises greater advantages, and sodium hydroxide may be the most convenient. However, several considerations must be taken into consideration to achieve efficiency during the flocculation process: dosage, cell concentration and type of microalgae are crucial for this process. Therefore, we investigated doses of 0.5N NaOH and time needed to achieve optimum flocculation pH to harvests at high density (>50x106 cells·ml-1) Nannochloropsis oculata. Whit 17 ml·l-1 de NaOH 0.5N can achieve high efficiency of flocculation (94.9%) at low pH (9.7), in short time (<60 min.). Also, we generate a concentrate for used as food for rotifers; the result was exponential growth of the population. It was also demonstrated that cells from the supernatant fraction (byproduct of the process) are viable for reuse as inoculum. We conclude that 0.5N NaOH is a practical and economic flocculant to generate concentrates of N. oculata for aquaculture purposes.


Rojo Cebreros A, Morales-Plascencia M, Ibarra-Castro L, Martínez-Brown J, Medina-Jasso M. Flocculation of Nannochloropsis oculata induced by sodium hydroxide: flocculation efficiency, viability effect on microalgae and their use as food for rotifers. Lat. Am. J. Aquat. Res.. 2017;44(4). Available from: doi:10.3856/vol44-issue4-fulltext-1 [Accessed 24 Jan. 2019].
Rojo Cebreros, A., Morales-Plascencia, M., Ibarra-Castro, L., Martínez-Brown, J., & Medina-Jasso, M. (2017). Flocculation of Nannochloropsis oculata induced by sodium hydroxide: flocculation efficiency, viability effect on microalgae and their use as food for rotifers. Latin American Journal of Aquatic Research, 44(4). doi:http://dx.doi.org/10.3856/vol44-issue4-fulltext-1