Applied Studies on Desmids and Other Conjugating Algae (Zygnematophyceae, Streptophyta)

Abstract

The conjugating algae (Zygnematophyceae, Streptophyta) have been primarily used as a model and test organisms for the study of many biological processes. Recent investigations demonstrated that they might have fair potential to be used for the commercial production of various metabolites as well as for the bioremediation of wastewaters. Due to the adaptation to high light intensities, Zygnematophyceae typically have high amounts of photosynthetic pigments, among which zeaxanthin and lutein have a precious role in medicine and agriculture. Furthermore, under certain conditions, some conjugating algae may produce astaxanthin, gallotannins, heat shock proteins (hsps), and antioxidant enzymes, which have nutraceutical and pharmaceutical significance. High amounts of several fatty acids (FAs), such as palmitic, oleic, linoleic, and α-linolenic acid, have been recorded in desmids (order Desmidiales), and these FAs may have an important role in cosmetics and industry as well as for biodiesel production. Some conjugating algae (e.g., Spirogyra sp.) have high biomass productivity and may accumulate large amounts of carbohydrates, 2representing a suitable substrate for bioethanol and hydrogen production. Furthermore, fresh and dried biomass of several representatives of the families Desmidiaceae and Zygnemataceae appeared efficient substrate for the biosorption of metals (As, Cd, Pb, Cu, Mn, Zn, Cr, Sr, Ba, Pb, Ni, and Hg), toxic substances, remedy residues, and nutrients, thus rendering this group interesting for the purification of various types of agricultural and industrial wastewaters.