Influence of Different Light Intensities on the β-carotene Production by Green Alga Coelastrella oocystiformis

Abstract

Microalgae are a broad, underutilized source of beneficial compounds to the pharmaceutical industry with both preventive and therapeutic applications in pharmacy and medicine. The concentration of β-carotene in algae is heavily influenced by light intensity. The present work investigated the varying light intensity’s effect (26, 43, 60, 86) µmol m-2 s-1 on the β-carotene composition and growth rate of the green algae Coelastrella oocystiformis cultured in Chu-10 medium with a fixed temperature of 28°C. In addition, the green algae Coelastrella oocystiformis, one of the Chlorophyta species, are distinguished by a spindle-shaped with pointed ends. In contrast, the mature cells are usually ellipsoid or oval. The results showed that the light intensity that reaches the algae positively impacts its pigment concentration and growth rate. As a result, the greater concentration of β-carotene reached 0.33 µg/mg was observed at 60 µmol m-2 s-1, while the smaller concentration of β-carotene at 0.04 µg/mg was detected at 26 µmol m-2 s-1. This resulted in the optimum light intensity, leading to a good production of β-carotene by alga understudy. Also, the statistical analyses at P<0.05 supported these consequences. Besides, the BLAST findings of microalgae 18S rRNA gene sequences indicated high percentage similarities 99% that showed the species Coelastrella oocystiformis strain SAG 277-1. The isolate Coelastrella oocystiformis with accession number: MW929196.1. is deposited in the NCBI GenBank.