Commercial Production of Fucoidan From New Zealand Undaria pinnatifida (Harvey) Suringar
Undaria pinnatifida is an invasive seaweed species in New Zealand that heavily infests mussel farms throughout the country. Fucoidan, one of the main cell wall polysaccharides of U. pinnatifida has numerous proven health benefits and has received increasing attention from researchers and entrepreneurs globally, but no commercial scale extraction of fucoidan from NZ U. pinnatifida has been undertaken to date. In 2010 the harvest and farming of this seaweed were permitted by the Biosecurity arm of the Ministry of Primary Industries (MPI), opening up the possibility of commercial scale harvest of the seaweed and production of fucoidan. In this thesis I investigated several aspects of the commercial production of fucoidan.
The objectives of this study were to investigate a) the impact on fucoidan yield and quality of the amount time taken to defrost frozen seaweed prior to fucoidan extraction, b) the optimal extraction time, temperature and seaweed: water ratio, and c) the ability to scale up proven laboratory size extraction methods to a commercial scale.
My results suggest that it is acceptable to leave thawed U. pinnatifida at 4°C for up to two weeks before fucoidan extraction, with no loss of total crude fucoidan and no significant changes in several of the “quality” parameters, i.e. fucose and sulphate content of extracted fucoidan. In terms of optimal extraction conditions, neither the length of extraction time (2, 3 and 4 hours) nor the temperatures tested (60, 70 and 80°C) had any significant impact on fucoidan yield or quality. The most influential factor in these experiments was the seaweed-to-water ratio, which had significant impact on both the fucoidan yield and the percentage of the larger than 10 kDa fucoidan fraction, the two most important factors considered in the fucoidan production in this thesis. Essentially the greater the water: seaweed ratio, the more fucoidan was extracted.
Two commercial private sector partners were engaged to a) harvest, chop and transport approximately 12 tonnes of U. pinnatifida to a frozen storage facility (this company is named P1), and b) to carry out pilot fucoidan production using the extraction techniques optimised in experiments above and a 10-kDa membrane to recover the fucoidan from the extract (this company is named P2). While producing fucoidan at a laboratory scale is somewhat routine, there were significant issues with the scale up from a number of angles.
Two pilot scale trials for extraction and collection of fucoidan were run with the other private sector partner (P2). The first Trial was not successful, yielding only 0.72 kg of fucoidan, where the amount of seaweed processed in this trial should have yielded at ~3.9 kg. Following this trial, a number of changes were made: a) increasing the seaweed-to-water ratio, b) “washing” the extracted seaweed in a further 1000 L of water, and c) dewatering the alginates more thoroughly to lower losses at this stage by hanging the wet alginate in a sack overnight.
Even with these modifications, Trial 2 was also unsuccessful in producing the expected amount of fucoidan using the membrane filtration method. However, by taking samples at each step, we found that the extraction time, temperature and seaweed:water ratio were sufficient for good recovery of the fucoidan. The washing step was also successful, delivering an extra 0.41 kg of crude fucoidan. Furthermore, the change to the way the alginates were precipitated in Trial 2 also reduced the loss in fucoidan. The main loss was identified to be in the final 10-kDa membrane filtration step. There was an 85.3% drop from the preceding stage, ending up with a projected 1.08 kg of crude fucoidan, some 92% less than expected.
In summary, the attempt to scale up from the laboratory to a commercial scale to produce fucoidan was unsuccessful in terms of using a 10-kDa membrane to collect the extracted fucoidan. However, the extraction of the fucoidan and precipitation of alginate stages were successful and, if coupled with a different fucoidan collection/precipitation method, will lead to successful production of large quantities of fucoidan.