Abstract
Wastewater from oil refineries, as well as other chemical industries, has specific features. Phototrophic microorganisms are commonly used to treat wastewater containing toxic components, such as oil and petroleum products. Cultivating microalgae and cyanobacteria in nutrient-rich wastewater can yield high biomass for simultaneous biotreatment, making it a more cost-effective and environmentally friendly approach. This study investigated the species composition of microalgae in wastewater from oil refineries in the Atyrau region. The results showed that Cyanophyta representatives dominated the microalgae composition in the enrichment culture. The presence of cyanobacteria in the wastewater was attributed to the high nutrient and calcium content of the organic matter. An axenic culture of the cyanobacterium Anabaena sp. was isolated to study its ability to grow and degrade different concentrations of motor oil. The results indicate the potential of Anabaena sp. strain in remediating aquatic environments contaminated with petroleum products.