The role of salt stress on laboratory cultivation of green macroalga Enteromorpha compressa and its antioxidant activity

Sanaa Shanab,Emad Shalaby

doi:10.21123/bsj.2021.18.1.0054

Abstract

Cultivation of the green seaweed Enteromorpha compressa was performed under natural laboratory spring environmental conditions of temperature, light intensity and photoperiod to study the salinity tolerance of this intertidal green macroalga. Cultivation was carried out under artificial seawater (ASW) of different concentrations (18, 35, 53 and 106 g/l sea salt) compared to the control using natural seawater (NSW). Growth rate and pigment content of the cultivated alga were recorded at regular intervals during the experimental duration. Antioxidant activity of the crude ethanolic extract and its fractions (petroleum ether, chloroform, ethyl acetate and acetone) was performed against DPPH radical scavenging assay and compared to the standard synthetic antioxidant butylated hydroxy-toluene (BHT). The finding showed that enhancement of algal growth rate under ASW concentrations of 35, 53 and to a lesser extent at 106 g/L during the first 15 days of cultivation were due to the increased pigment biosynthesis, photosynthetic and metabolic activities and followed by gradual retardation due to the impact of prolonged salt stress. Antioxidant activity of alga was found to be concentration, type of extract and incubation time dependent. Acetone fraction of all salt concentrations showed higher antioxidant activity compared to other fractions. Pronounced activity was recorded at higher seawater conc. (106g/l).

Highlights

Macroalgae, known as seaweeds, can be classified based on the nature of their pigments into brown seaweeds (Phaeophyta), red seaweeds (Rhodophyta) and green seaweeds (Chlorophyta) [1]
Enteromorpha spp is recommended for human consumption because it has several beneficial components, such as minerals, protein, essential amino acids, essential fatty acid, and fiber [16]
It is known that algal cultivation under salt stress conditions, physiological and metabolic alterations may occur accompanied by an increased production of reactive oxygen species (ROS)

Summary

Introduction

Macroalgae, known as seaweeds, can be classified based on the nature of their pigments into brown seaweeds (Phaeophyta), red seaweeds (Rhodophyta) and green seaweeds (Chlorophyta) [1]. This investigation aims to determine the antioxidant activity of successive extracts from the green macroalga Enteromopha compressa cultivated in laboratory natural conditions under different artificial sea salt concentrations as compared with sea salts (control treatment).

Results

Conclusion