The microalgal culture was harvested by flocculation (by increasing the pH using NaOH). The nutrient profiling showed lower values of major nutrients as compared to the reported values.
There are lot of flocculation methods to harvest the cultured microalgae, if the present pH method not suitable by using other methods to make aquaculture feed from microalgae. Anyhow it is good idea to make pellet feed for fishes.
You might have a look at the work of Knukey et. al. : http://www.sciencedirect.com/science/article/pii/S0144860906000343.
If the protein % exceeds 50%, it can be a potential source/raw materials for fish feed
Dear Dr. Sandeep,
Since pH increasing method is reducing the nutritional value of algae, you may use nylon screens of varying sizes for collecting algal biomass. You have not mentioned for which species and at what stage the flocculated algae to be used. Some algal species form into clumps. The clumps remain even after application in the system. For example it dead algae remain in larval rearing tanks, it may develop ciliates and attack the larvae. It may used as one of the protein source in formulation of feeds for different aquaculture species.
would be skeptical regarding comparison with reported values. Would not expect the composition would change during the flocculation step. However, stability during storage may change and it may have an effect on your analytics.
thank you all for the valuable suggestions. The species I am working are Nannochloropsis oculata, Dunaliella salina and Chlorella vulgaris.
Dear Mr. Sandeep, I am working on the production of a microalgae paste (Nannochloropsis oculata) by flocculation. I've been experimenting it in the rearing of juvenile seahorses and the performance of the seahorses grown with the flocculated paste is similar to the ones grown with fresh microalgae culture. So it seems that this paste that we had produced can replace the fresh microalgae culture. I also stored the paste for some weeks and the protein and carbohydrates contents remain constant, and the cells were viable and continue to reproduce.
hi Mr Rafael Sales, that is really interesting. We are also in work to make an algal paste with multiple species which can give enhanced nutrition to the larvae. Thank you for sharing the information.
Hi Mr. Sandeep, this paste that you are developing is also produced by flocculation? I consider the regulation of the paste's nutritional value as very important. Good luck on your research!
Hi Mr. Rafael Sales, That is our plan of research. Thank you very much.
Hello
We work with some species of microalgae and we use floculation, i think that depends of the type of floculant; if you use an inorganic product as aluminum sulfate (alum) and ferric chloride you can get a high rate of floculation but is reported that could remains some traces of these materials in the biomass, if you want to produce biofuels this will not be a problem but in the case of aquaculture maybe is better to use some organic floculants as cationic starch or quitosane is reported that Organic flocculants are naturally available, biodegradable, and inexpensive.
you can read more about the effects of floculants in this paper: http://www.sciencedirect.com/science/article/pii/S0960852413014521
i hope this help you
Good luck
http://www.sciencedirect.com/science/article/pii/S0960852413014521
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