Abstract Description

Biofilm formation in industrial water systems disrupts equipment efficiency and increases public health issues. These complex microbial communities adhere to surfaces using self-produced extracellular polymeric substances, making it notoriously difficult to eradicate. As a sustainable alternative, combining biocides with eco-friendly biosurfactants, such as lyso-ornithine lipids (LOL), is emerging as a promising next-generation strategy for effective biofilm control. Thus, this study aims to develop a new and improved co-formulation of a proprietary biocide with LOL to enhance antibiofilm efficacy and yield an all-natural treatment solution. Wastewater collected from a Cooling tower was used to cultivate a heterogeneous biofilm in a continuous-flow cell system for 14 days and treated with 10 µg/mL LOL and 150 ppm Decont A for 48 h. Biofilm structure, dispersal, and planktonic cell yield were assessed using light microscopy, colony-forming units, fluorescein diacetate, and flow cytometry. DNA was extracted, amplified, and sequenced via Oxford Nanopore technology for metagenomic analysis of microbial community composition and dynamics. Both qualitative and quantitative analyses demonstrated a progressive biofilm development, with initial microcolonies forming and reaching a steady state after 3 days of cultivation. Treatment with Decont A and LOL coformulation disrupted biofilm structure. This was consistent with a steady increase in planktonic cell yield from biofilm, which was in parallel with biofilm dispersal. On the contrary, cell viability increased during acute treatment (≤ 7 h) but decreased in long-term treatment (48 h). Preliminary metagenomic analysis has revealed that the dominant taxa in the cooling tower water belong to Caulobacteraceae, Sphingomonadaceae, Rhodobacteraceae, Rhizobiaceae, Comamonadaceae, Hyphomonadaceae, Burkholderiaceae, and Pseudomonadaceae. Both LOL and its coformulation with Decont A altered the dominant microbial taxa and significantly affected representatives enriched in antibiotic resistance genes. This data indicates that LOL improves the antibiofilm efficacy of Decont A. Altogether, this supports the biocide-biosurfactant coformulations as a potential approach for sustainable biofilm management.