Ecological role of GSN3 in natural biofilm formation and its advantages in bioremediation.

This study assessed the role of a new strain, GSN3, with biofilm-forming and phenol-degrading abilities. Three biofilm reactors were spiked with activated sludge (R1), green fluorescent plasmid (GFP) tagged GSN3 (R2), and their combination (R3). More than 99% phenol removal was achieved during four weeks in R3 while this efficiency was reached after two and four further operational weeks in R2 and R1, respectively. Confocal scanning electron microscopy revealed that GSN3- strains appeared mostly in the deeper layers of the biofilm in R3. After four weeks, almost 7.07 × 10 more attached sludge cells were counted per carrier in R3 in comparison to R1. Additionally, the higher numbers of GSN3- in R2 were unable to increase the efficiency as much as measured in R3. The presence of GSN3- in R3 conveyed advantages, including enhancement of cell immobilization, population diversity, metabolic cooperation and ultimately treatment efficiency.