Enhanced attached growth of microalgae Scenedesmus. LX1 through ambient bacterial pre-coating of cotton fiber carriers

•Algal films were cultivated on bacteria and EPS-coated cotton carriers in an sspBR.•Sterile and non-sterile bacterial coatings enhanced the attachment of microalgae.•The physicochemical properties of microalgae were influenced by ambient bacteria.•Microalgae cultivated on bacteria coated carriers had the highest protein content.