Stephanie Brain-Isasi1, Sebastián Correa2, Alejandro H. Buschmann3, Carolina Camus3, María Elena Lienqueo2
1Department of Protein Analysis and Purification, Luyef Biotechnologies Inc., Santiago, Chile, 7830490
2Centre for Biotechnology and Bioengineering, Faculty of Physical and Mathematical Sciences, Universidad de Chile, Santiago, Chile, 8370456
3Centro i~mar, Universidad de Los Lagos & Centre for Biotechnology and Bioengineering (CeBiB) & Millennium Nucleus Marine Agronomy of Seaweed Holobionts (MASH), Puerto Montt, Chile, 5502096
The red alga Gracilaria chilensis C. J. Bird, McLachlan & E. C. Oliveira (Agarophyton chilense Gurgel, J.N.Norris & Fredericq) is one of the few algae commercially farmed in Chile, where this alga is commonly named “Pelillo”. Its main by-product is agar, a gelling agent used in the food and pharmaceutical industries. This alga is also a valuable feedstock for the biorefinery of phycobiliproteins (PBPs), coloured and fluorescent water-soluble proteins with industrial applications.
This work aimed to valorise G. chilensis by sequentially extracting PBPs and agar. After freeze-thaw treatment, we extracted two PBPs: R-phycoerythrin (R-PE) and R-phycocyanin (R-PC). After two purification steps, we recovered both PBPs from crude extract (R-PE = 0.20 mg/g DW and R-PC = 0.23 mg/g DW) with a purity index >2, making them suitable for food applications. After PBPs extraction, we recovered agar from the residual algal matter.
There were no significant differences between the physical parameters of agars obtained after PBP extraction and those from agars directly extracted from G. chilensis (melting and gelling temperature, and agar deformation). The agar yield after PBPs extraction was 24.9±1.0 % and showed gel strength of 726±182.9 g/cm2, whereas agar directly extracted from alga yielded 23.1±2.0 % with gel strength of 730.5±96.9 g/cm2. The agar obtained after PBPs extraction allowed the microbial growth and the effective separation of nucleic acids, resulting in a low-cost alternative for DNA electrophoresis without agarose purification.
Our results demonstrate that the method proposed allowed the simultaneous extraction of PBPs and agar from G. chilensis.