Polysaccharide Content and Growth Rate of Lessonia Variegata J. Agardh: Investigating its Potential as a Commercial Species

Abstract

The endemic brown alga Lessonia variegata has recently been shown to be four separate lineages. To determine differences between the four morphologically similar lineages, the economically valuable polysaccharides alginate and fucoidan were extracted and yields from each of the lineages were compared. In order to determine seasonal patterns in the yield of alginate and fucoidan, and the growth rate within L.variegata, polysaccharides were extracted and the growth rate measured on a monthly basis from March 2010 until February 2011 on plants from the Wellington lineage. The alginate and fucoidan yields were obtained via stepwise extraction with dilute acid and sodium carbonate as per the previously published methods of Usov et al. (1985). The growth rate of L. variegata from the Wellington lineage was assayed using the hole punch technique first described by Parke (1948). The yield of alginate within the Wellington lineage of L. variegata fluctuated seasonally with the highest percent occurring in spring and summer 2010. The yield of fucoidan in the Wellington lineage was at its highest in mid-autumn and late spring 2010. Two different growth rates were detected for the Wellington lineage of L. variegata. There was a period of significantly high growth from late winter 2010 until late summer 2011.The Wellington lineage had the lowest yield of alginate and the highest yield of fucoidan compared to the Northern lineage, the Kaikoura lineage and the Southern lineage. Based on the findings of this study, an appropriate harvest period for the Wellington lineage of L. variegata would be in early to mid-summer when polysaccharide yields and growth rates are high and the alga is vegetative.