Bacterial cell numbers and community structures of seawater biofilm differed depending on the attachment substratum. Seawater biofilm on plastic and metal surfaces

This study evaluates the differences in total cell counts and the microbial community structure of seawater biofilm attached on high density polyethylene (HDPE), polycarbonate, stainless steel (SS316) and titanium coupons. All four types of coupons have hydrophilic surfaces but exhibit differences in their surface characteristics. Specifically, the polycarbonate coupon exhibits a significantly higher surface roughness than the other coupons. There was a corresponding higher number of cells attached on polycarbonate. Throughout the four month sampling period, the number of attached cell numbers on SS316 were significantly lower than that attached on the other materials. However, there was also a higher relative abundance of certain bacterial populations, namely sulfate-reducing bacteria, as well as genera Acinetobacter and Coxiella in the seawater microbial biofilm on SS316. Quantitative PCR further verified that the copy numbers of genes representing the presence of Desulfobacteraceae and Desulfobulbaceae were approximately 10-fold higher in biofilm sampled from SS316 than that sampled from other materials. Although cell numbers attached on SS316 are lower, the enrichment of sulfate-reducing bacteria in the biofilm associated with SS316 indicates that this material may be more prone to microbial-induced biocorrosion when used as a piping material in most seawater-associated industrial applications.