Revision of Coelastrella (Scenedesmaceae, Chlorophyta) and first register of this green coccoid microalga for continental Norway

Abstract

A terrestrial green microalga was isolated at Ås, in Akershus County, Norway. The strain corresponded to a coccoid chlorophyte. Morphological characteristics by light and electron microscopy, in conjunction with DNA amplification and sequencing of the 18 s rDNA gene and ITS sequences, were used to identify the microalgae. The characteristics agree with those of the genus Coelastrella defined by Chodat, and formed a sister group with the recently described C. thermophila var. globulina. Coelastrella is a relatively small numbered genus that has not been observed in continental Norway before; there are no previous cultures available in collections of Norwegian strains. Gas chromatography analyses of the FAME-derivatives showed a high percentage of polyunsaturated fatty acids (44–45%) especially linolenic acid (C18:3n3; 30–34%). After the stationary phase, the cultures were able to accumulate several carotenoids as neoxanthin, pheophytin a, astaxanthin, canthaxanthin, lutein, and violaxanthin. Due to the scarcity of visual characters suitable for diagnostic purposes and the lack of DNA sequence information, there is a high possibility that species of this genus have been neglected in local environmental studies, even though it showed interesting properties for algal biotechnology.

Thermo resistant antioxidants from photoautotrophic microorganisms: screening and characterization

“…The ethanol extracts of selected strains were analysed by HPLC, in order to collect more information about the specific pigments (carotenoids and chlorophylls). The main peaks of each species were identified (Moore et al 1995;Graziani et al 2013;Goecke et al 2020;Zimermann et al 2020). The overall picture showed a high variability of xanthophylls, both identified and not identified, among samples.…”

A Fast-Growing Oleaginous Strain of Coelastrella Capable of Astaxanthin and Canthaxanthin Accumulation in Phototrophy and Heterotrophy

“…The cells possessed meridional ribs that connected one pole of the cell to the other and formed polar thickenings at each of them. These ornamentations, i.e., meridional ribs, and morphological features are characteristics of the Coelastrella genus [ 16 , 46 , 47 ].…”

“…K-1 (MK330664) (aLRT = 1.0). Although the Coelastrella genus does not appear monophyletic [ 16 , 17 , 48 ], the morphological and phylogenetic analyses suggest that the isolate is strongly related to the genus Coelastrella , and it was thus named Coelastrella sp. S6 ( Figure 2 ).…”

“…The genus Coelastrella belongs to the Chlorophyta phylum, to the Sphaeropleales order, and to the Scenedesmaceae family, and it is peculiar because the cell wall, composed of two layers—the internal wall being made of cellulose, and the external wall being made of sporopollenin, presents meridional ribs connecting the two poles of the cell [ 16 , 17 , 18 ]. Some strains/species with biotechnological relevant properties, such as the presence of astaxanthin and canthaxanthin, have been described, mainly selected in Asia or East Europe (e.g., [ 8 , 13 , 19 , 20 ].…”

Photoautotrophic and Mixotrophic Cultivation of Polyhydroxyalkanoate-Accumulating Microalgae Consortia Selected under Nitrogen and Phosphate Limitation

“…The morphology of the microalgae cells was observed using a light microscope (Olympus C011) and SEM (Hitachi, TM4000Plus). The microalgae species were morphologically identified according to relevant keys suggested by Goecke et al [32], Hegewald [33], and Hašler et al [34]. Transmission electron microscopy (TEM) (Philips, TECNAI 20) was used to observe the PHA granules inside the microalgae cells.…”