Bio-sorption of methylene blue and production of biofuel by brown alga Cystoseira sp. collected from Neom region, Kingdom of Saudi Arabia

Abstract

The risks and challenges of the NEOM project on water bodies can be somehow resolved by using Cystoseria sp., a brown-green macroalga, and natural renewable resource species, which are appealing due to their sustainability, cost-effectiveness, and eco-friendliness. Lipid was extracted from Cystoseria sp. collected from Sharma beach, Neom, Tabuk, Kingdom of Saudi Arabia. It was treated with different solvents, petroleum ether, methanol, and petroleum ether:methanol (1:1), to obtain biofuel. Petroleum ether and methanol were the most significant solvents for extractions of six different hydrocarbon compounds, followed by methanol. Tetrahydradecane 5-methyl 60.03% in petroleum ether, 59.51% in methanol, and 51.39% in petroleum ether:methanol is obtained. Removal of 10 mg·L−1 methylene blue (MB) by alga using 0.2 g·L−1 of Cystoseria sp. and its residues after methanol extract was achieved in 120 min. Zeta potential analysis of alga confirms that different negative charges on adsorbent surfaces undergo conformational change with different solvents and adsorb the positively charged MB via electrostatic interaction force. The production of bioethanol efficiency percentage from Cystoseria sp. ranges from 5% to 68.97%. Hence, Cystoseria sp. can be a renewable resource to yield biodiesel and bioethanol and eliminate MB from wastewater, maintaining environmental sustenance and economic development.

Keywords

• cystoseria sp.
• bioethanol
• biodiesel
• phycoremediation
• cytotoxicity