Adhesion of microorganisms in the marine environment is one of the initial events responsible for the occurrence of biofouling. A variety of factors play roles in regulating adhesion behaviors and subsequent biofilm formation. Here the study was focused on the influence of the typical marine polysaccharide alginate and the protein albumin on the attachment and colonization of Bacillus sp., Chlorella pyrenoidosa and Phaeodactylum tricornutum to silicon wafers in sterile artificial seawater. The rapid formation of conditioning layers due to the adsorption of the molecules was revealed by atomic force microscopy, and porous layers with the thickness of 3-6 nm further altered the surface roughness and wettability of the substrata. The presence of alginate or albumin in the culture solution tailored the surface properties of C. pyrenoidosa and P. tricornutum. The thickness, structure heterogeneity, biomass, diffusion distance, and roughness coefficient of the biofilm formed by colonization of the microorganisms were examined and their values showed that alginate/albumin had a significant influence on biofilm formation. The results are relevant to biofouling research on exploring antifouling strategies at the molecular level
