Isolation, Identification, and Biochemical Characteristics of a Cold-Tolerant Chlorella vulgaris KNUA007 Isolated from King George Island, Antarctica

Abstract

A cold-tolerant unicellular green alga was isolated from a meltwater stream on King George Island, Antarctica. Morphological, molecular, and biochemical analyses revealed that the isolate belonged to the species Chlorella vulgaris. We tentatively named this algal strain C.vulgaris KNUA007 and investigated its growth and lipid composition. We found that the strain was able to thrive in a wide range of temperatures, from 5 to 30 °C; however, it did not survive at 35 °C. Ultimate analysis confirmed high gross calorific values only at low temperatures (10 °C), with comparable values to land plants for biomass fuel. Gas chromatography/mass spectrometry analysis revealed that the isolate was rich in nutritionally important polyunsaturated fatty acids (PUFAs). The major fatty acid components were hexadecatrienoic acid (C16:3 ω3, 17.31%), linoleic acid (C18:2 ω6, 8.52%), and α-linolenic acid (C18:3 ω3, 43.35%) at 10 °C. The microalga was tolerant to low temperatures, making it an attractive candidate for the production of biochemicals under cold weather conditions. Therefore, this Antarctic microalga may have potential as an alternative to fish and/or plant oils as a source of omega-3 PUFA. The temperature tolerance and composition of C.vulgaris KNUA007 also make the isolate desirable for commercial applications in the pharmaceutical industry.

Taxonomy and Ecology of Marine Algae

“…Jo et al [12] investigated the growth and lipid composition of the algal strain C. vulgaris KNUA007. They found that the strain was able to thrive in a wide range of temperatures, from 5 to 30 • C; however, it did not survive at 35 • C. The microalga was tolerant of low temperatures, making it an attractive candidate for the production of biochemicals under cold weather conditions.…”

Epiphytic microalgae community as aquatic bioindicator in Brantas River, East Java, Indonesia

“…Chlorophyta plays an important role in the global carbon, nitrogen and phosphorus cycle. This group of microalgae has a high tolerance for weather conditions (Woo Jo et al 2020).…”

Identification and Quantification of Glycans in Whole Cells: Architecture of Microalgal Polysaccharides Described by Solid-State Nuclear Magnetic Resonance

“…So far, information can only be deduced from Chlorella , another genus within the same Chlorellaceae family. The Chlorella genus is also debated, even if this group is described as pyrenoid-containing alga-clade, and is one of the most-studied phototrophic eukaryotes, with more than 100 strains described, compassing 37 taxonomically acknowledged species 57 found in freshwater, marine, and soil habitats. 58 , 59 In general, the most abundant monosaccharides identified in Chlorella and Parachlorella cell walls are glucose, galactose, and rhamnose, 13 , 60 which are glycan units commonly associated with cell surface interactions in algae and in bacteria.…”

“…So far, information can only be deduced from Chlorella , another genus within the same Chlorellaceae family. The Chlorella genus is also debated, even if this group is described as pyrenoid-containing alga-clade, and is one of the most-studied phototrophic eukaryotes, with more than 100 strains described, compassing 37 taxonomically acknowledged species found in freshwater, marine, and soil habitats. , In general, the most abundant monosaccharides identified in Chlorella and Parachlorella cell walls are glucose, galactose, and rhamnose, , which are glycan units commonly associated with cell surface interactions in algae and in bacteria. , Most publications agree that Chlorella microalgae generally contain cellulose (rich in Iα allomorph) and alkali-soluble hemicellulose, − but other assemblies have also been reported, such as acidic polysaccharides containing arabinogalactan, glycoproteins, phosphorylated β-galactan, as well as chitin-like and other glycan-rich cell walls. ,− …”