Morphological, Molecular, and Biochemical Characterization of Astaxanthin-Producing Green Microalga Haematococcus sp. KORDI03 (Haematococcaceae, Chlorophyta) Isolated from Korea

Abstract

A unicellular red microalga was isolated from environmental freshwater in Korea, and its morphological, molecular, and biochemical properties were characterized. Morphological analysis revealed that the isolate was a unicellular biflagellated green microalga that formed a non-motile, thick-walled palmelloid or red aplanospore. To determine the taxonomical position of the isolate, its 18S rRNA and rbcL genes were sequenced and phylogenetic analysis was performed. We found that the isolate was clustered together with other related Haematococcus strains showing differences in the rbcL gene. Therefore, the isolated microalga was classified into the genus Haematococcus, and finally designated Haematococcus sp. KORDI03. The microalga could be cultivated in various culture media under a broad range of pH and temperature conditions. Compositions of the microalgal cellular components were analyzed, and its protein, carbohydrate, and lipid compositions were estimated to be 21.1 ± 0.2%, 48.8 ± 1.8%, and 22.2 ± 0.9%, respectively. In addition, D-glucose and D-mannose were the dominant monosaccharides in the isolate, and its amino acids were composed mainly of aspartic acid, glutamic acid, alanine, and leucine. Moreover, several polyunsaturated fatty acids accounted for about 80% of the total fatty acids in Haematococcus sp. KORDI03, and the astaxanthin content in the red aplanospores was estimated to be 1.8% of the dry cell weight. To the best of our knowledge, this is the first report of an Haematococcus sp. isolated from Korea, which may be used for bioresource production in the microalgal industry.

Astaxanthin-Producing Green Microalga Haematococcus pluvialis: From Single Cell to High Value Commercial Products

“…This microalga can be usually found in temperate regions around the world and has been isolated from Europe, Africa, North America, and Himachal Pradeslv India (Pringsheim, 1966 ; Suseela and Toppo, 2006 ). It has been also found across diverse environmental and climate conditions: in brackish water on the rocks on the seashore (Chekanov et al, 2014 ); freshwater basin in the rock filled with melted snow on Blomstrandhalvøya Island (Norway) (Klochkova et al, 2013 ); dried fountain near Rozhen, Blagoevgrad in Bulgaria Gacheva et al, 2015 , freshwater fishpond in Bihor, Romania (Dragos et al, 2010 ); rooftop surface of a building of KIOST in Seoul Korea (Kim et al, 2015 ). It is well suited for survival under conditions of expeditious and extreme in light, temperature, and salt concentration that would be deleterious to many other microalgae, due to its ability to encyst (become enclosed by thick membrane) in a rapid manner (Proctor, 1957 ).…”

“…pluvialis Rozhen-12 during green stage cultivation (Gacheva et al, 2015 ). It was estimated that proteins contribute to 21 (Kim et al, 2015 ) and 23% (Lorenz, 1999 ) of cellular content during red stage cultivation of H. pluvialis . Amino acid composition of proteins in the red stage indicated that proteins were mainly composed of aspartic acid, glutamic acid, alanine, and leucine with total amino acid content of 10.02/100 mg, 46.0% of which belonged to essential amino acids (Lorenz, 1999 ; Kim et al, 2015 ).…”

Characterization of an Oleaginous Unicellular Green Microalga, Lobosphaera incisa (Reisigl, 1964) Strain K-1, Isolated From a Tidal Flat in the Yellow Sea, Republic of Korea

“…The general morphology of the isolated microalga was investigated under a light microscope (LM) (Eclipse 80i; Nikon Co., Japan), and the size of cells was determined with an image analyzer (NIS-Elements BR 3.0; Nikon Co., Japan). For ultrastructural analysis, the microalgal cells were prepared as described previously ( Kim et al, 2015a , b ) and were examined at National Instrumentation Center for Environmental Management, Seoul National University, Seoul, Korea using a Field Emission SEM (AURIGA; Carl Zeiss, Germany) and TEM (JEM1010; JEOL Ltd., Japan), respectively.…”

“…The proportions of the crude major components (ash, carbohydrate, lipid, moisture, and protein) in lyophilized microalgal cells cultivated in aerated 5L flasks (BG-11 medium, pH 8.0) at 25°C under 100 μmol photons/m 2 /s light intensity (12 h:12 h light:dark cycle) for 14 days were determined according to the official methods of the Association of Official Analytical Chemists (AOAC) ( AOAC, 2006 ). The concentrations of amino acids, monosaccharides, and fatty acids (FAs) in the cells were determined as previously described ( Kim et al, 2015a ).…”

“…Since 2010, we have been screening several microalgal and cyanobacterial strains with advantageous characteristics of their cellular components for biotechnological applications ( Jeon et al, 2015 ; Kim et al, 2015a , b , 2017 ; Kim and Kang, 2016 ). Herein, we report the characterization of a unique indigenous strain of L. incisa isolated from a tidal flat in the Yellow Sea, Republic of Korea.…”