Seaweed extract manufacture

[SteveDevlin]

I am working on seaweed extract project, which involves the manufacture of extract by alkaline hydrolysis treatment. Seaweed powder is mixed with water and alkali solution and the reaction mass is heated to 50 degrees centigrade. The final product contains around 20 percent insoluble that need to be separated out and also the viscosity of the final product needs to be around 100 cps. Separation by filtration is not feasible because the mass is very viscous. I tried using a centrifuge but did not have any success.

Can someone please advise me how to reduce the viscosity of the extract/ remove the insoluble from the finished product?

Thanks,

Steve

 

[HEC]

You mentioned centrifuge, was this a separator or decanter or simply batch centrifuge? Is there a significant diference in SG between the components? More information is required.

Mark Hutton

 

[SteveDevlin]

Mark,

Thanks for your reply. The SG of the components are very close and I tried separating the components using Alfa Laval disc stack centrifuge but could not get the results. Using a separator/ decanter might not be of much help because it sediments very slowly.

Regards,

Steve

 

[HEC]

What component are you trying to recover? The solids or the liquid component? You may need to reduce the viscosity by addition of more water/solvent and then use a filter press for recovery of the solids. What hygiene/food/pharma standards do you need to work to? Contact me directly on hutton4eng@picknowl.com.au
Cheers

Mark Hutton

 

[SteveDevlin]

I appreciate your help a lot, Mark. I am interested in the liquid component that contains active ingredients. Dilution by water (solvent cannot be used) will reduce the concentration of these active ingredients because the filtered solution cannot be evaporated to reduce the water content. The higher temperatures will affect the active ingredients during evaporation.

After the alkaline extraction of seaweed the resulting mass has the consistency of “pudding”J. I did try doing filtration but the rate was very slow and also the amount of filtrate got was very less because the liquid was still entrained within the insoluble cellulose. Using a filter aid doesn’t help either, and to reduce the viscosity I am presently experimenting with viscosity modifiers.

It’s an interesting problem and there isn’t much information available on the internet. Thank you so much for your valuable inputs.

 

[HEC]

Steve,

Dilution by water may still be viable, in fact it may be worth looking at "washing" the actives out of the cellulose. Accept that the active is temperature sensitive, so use freeze dryer to get the active as a powder. Economics of the process are determined by value of the active. If it is a high value active then the additional cost of equipment and energy is worthy of the cost. If it is a relative low value active, then you are stuck! Sounds like a very interesting project.

Mark Hutton

 

[nbucska]

If the particle size of the "sea=weed powder" would be larger, the extraction time would increase and the filtering time decrease. Couldn's find you an optimum?

What about freeze drying or vacuum evaporation?
Chemical of physical precipitation ?

Can you tell us what the product is ?



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[SteveDevlin]

Thank you for your replies, Mark and nbucska.

Mark you are absolutely right, the active ingredient, which is commercially known as seaweed extract is temperature sensitive. I don’t have information on freeze drying so forgive me for asking this, would it be possible to freeze dry a viscous material that has the consistency of “pudding” and then extract out the active ingredient? I will definitely do some research on this over the weekend.

The market price for the product is around $5 per liter and we are planning to manufacture around 1000 liters per day. It definitely is an interesting project and has been giving me sleepless nights

Nbucka

The process of seaweed extraction involves alkaline hydrolysis wherein seaweed powder is reacted with an alkali at a temperature of around 60 degrees centigrade. Unfortunately after completion of the reaction the mass is very viscous and has insolubles like cellulose. Seaweed extract is used in fertilizer applications and hence the final product needs to be 100% water-soluble.

Steve

 

[HEC]

Steve,

Freeze drying is a process similar to Arctic conditions, cold bone dry air is passed over the mixture to evaporate moisture. This can be asisted by performing the process in an evacuated container (vacuum). It puld certainlly be feasible to dry the "pudding" to a powder, the issue now would be how to extract the active? Dry cyclone, sieve?

Regards

Mark Hutton