Surface modification of an organic hessian substrate leads to shifts in bacterial biofilm community composition and abundance

Antifouling strategies to limit biofilms on submerged surfaces in the marine environment are of particular interest due to the economic and environmental impacts in industries such as shipping and aquaculture. Here, we investigate the influence of chemically modified hessian bag surfaces on the bacterial abundance and community composition of biofilm formation using flow cytometry and 16S rRNA pyrosequencing. Hessian bags were coated with 5% and 10% Propyl(trimethoxy)silane (PTMS) and half of the bags had their lignin and hemicellulose removed via NaOH mercerisation. Significantly lower bacterial abundance was observed on mercerised bags treated with 5% PTMS (p < 0.01). Significant shifts in bacterial taxa were also observed (p = 0.0004), whereby unmercerised bags exhibited higher relative abundances of the anaerobic family Desulfovibrionaceae (4.5 ± 1.7%), while mercerised bags displayed higher relative abundances of the aerobic family Phyllobacteriaceae (3.6 ± 1.7%). This suggests that the mercerisation process may lower colonization rates and subsequently produce a thinner biofilm. This hypothesis is strengthened by the lower abundance of bacteria on mercerised bags, particularly on the 5% PTMS coating. Our results show that modifying a hessian surface via non-toxic coating and mercerisation reduces biofilm formation and also shifts the dominant taxa, increasing our understanding of antifouling strategies in the marine environment.