Developments in Biotechnology of Red Algae

Abstract

The red algae are unique and interesting for their ancient eukaryote position, the diversity of their cellular structure and biochemical composition, and their high species diversity and commercial value. Red algae contain the largest number of commercially valuable species of the three macroalgal groups, and include species cultivated and harvested as a source of food, phycocolloids, pharmaceuticals, nutraceuticals, and cosmetics. The red alga Porphyra (commonly called “nori”), for example, is eaten worldwide today and is the basis of a large-scaled cultivation industry in Japan and China. Other red algae are cultivated for the production of the phycocolloids agar and carrageenan, which are used as thickening and gelling agents in the food and pharmaceutical industries. The use of seaweeds as phycosupplements (soil additives, fertilizers, and animal feeds) is recently gaining importance in several countries. It is because of their considerable commercial value that red macroalgae were among the first for which modern biotechnology tools and techniques were successfully developed. Today, techniques for callus production, tissue culture, protoplast isolation, and fusion are available for virtually every commercially valuable red macroalgal species. Considerable efforts have been recently directed to develop genetic engineering technology aiming at the manipulation of biochemical pathways leading to higher product yields and improved strains. In addition, a great deal of molecular studies have also been conducted on red macroalgae. In particular, phylogenetic and evolutionary relationships have been investigated at many different levels using nuclear ribosomal, plastid, and mitochondrial markers. A brief update on the developments in red algal biotechnology is presented in this chapter.