Bacterial cell numbers and community structures of seawater biofilm differed depending on the attachment substratum

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.

本研究评估了附着于高密度聚乙烯（high density polyethylene, HDPE）、聚碳酸酯（polycarbonate）、不锈钢（stainless steel, SS316）及钛试样上的海水生物膜的总细胞数差异与微生物群落结构。四类试样均具有亲水表面，但表面特性存在差异。具体而言，聚碳酸酯试样的表面粗糙度显著高于其余三类试样，其表面附着的细胞数量也相应更高。在为期四个月的采样周期内，SS316不锈钢试样表面的附着细胞数显著低于其他材料。然而，SS316表面的海水微生物生物膜中，特定细菌类群的相对丰度更高，包括硫酸盐还原菌，以及不动杆菌属（Acinetobacter）和考克斯体属（Coxiella）。定量聚合酶链反应（quantitative PCR）进一步验证：从SS316表面采集的生物膜中，代表脱硫弧菌科（Desulfobacteraceae）与脱硫球茎菌科（Desulfobulbaceae）存在的基因拷贝数较其他材料采样组高出约10倍。尽管SS316表面的附着细胞数较低，但该材料相关生物膜中硫酸盐还原菌的富集现象表明，若作为多数海水相关工业应用的管道材料，SS316可能更易发生微生物诱导的生物腐蚀。