Periodic chemical cleaning with urea: disintegration of biofilms and reduction of key biofilm-forming bacteria from reverse osmosis membranes

Sanawar, Huma; Kim, L.H.; Farhat, Nadia; Loosdrecht, Mark C.M. van; Vrouwenvelder, Johannes S.

doi:10.1016/j.wroa.2021.100117

Cited by 14 publications

(1 citation statement)

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“…Since urea is a protein denaturant, its effect on biofilm may depend on EPS composition and protein content. Past studies have demonstrated biofilm weakening and enhanced biofilm removal ,, upon treatment with urea at concentrations ranging from 0.2 to 2 M. For example, Chen & Stewart (2000) reported 73% biofilm protein removal from binary biofilms of P. aeruginosa and Klebsiella pneumonia using 200 mM urea .…”

Section: Discussionmentioning

confidence: 99%

Beyond Microbial Inactivation: Unveiling the Potential of Detachment-Promoting Agents in Water Distribution System Biofilm Control

Kabir,

Hasan,

Aggarwal

2024

ACS EST Water

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Biofilms growing on the surfaces of water distribution systems (WDS) pose a significant problem for maintaining the quality of distributed drinking water. Current approaches to biofilm control by inactivating microbial cells (e.g., residual chlorine) involve high concentrations of antimicrobials, which can cause human health hazards, produce harmful byproducts, and still allow appreciable biofilm proliferation on WDS pipes. An alternate paradigm is to instead target the biofilm extracellular polymeric substances (EPS) through "detachment promoting agents" (DPAs) to cause EPS weakening, biofilm dispersal, and eventual detachment. Four potential DPAs (sodium triphosphate [STP], ethylene diamine tetraacetate [EDTA], citrate, and urea) were tested for biofilm detachment at concentrations ranging from 1 to 100 mM for their efficacy in disrupting single-species Staphylococcus epidermidis biofilms and multispecies (microbial consortium derived from WDS) biofilms grown on well plates and in glass capillary flow cells. The protein and polysaccharide contents of detached biofilms in flow cell effluents were also measured. The well-plate study on 24 h-old singlespecies and multispecies biofilms showed significant removal (P-value < 0.002) performance with citrate and STP. Capillary flow cell experiments were conducted with a 100 mM concentration of DPAs on 72 h-old single-species biofilms, 72 h-old multispecies biofilms, and 4-month-old chlorinated multispecies biofilms. From flow cell image analyses, the maximum dispersal for S. epidermidis biofilms (mean ± S.E.) was observed with EDTA (45 ± 13%), while 22−28% mean biofilm removal was observed with citrate, STP, and urea treatment. Multispecies biofilms (both 72 h and 4 months) were more resistant to DPA treatments than single-species S. epidermidis biofilms. The maximum EPS protein in detached biofilm clusters was observed with EDTA treatment, supporting the hypothesis of biofilm dispersal due to EPS weakening. Overall, the results show the effectiveness and early promise of DPAs for biofilm dispersal, offering an additional tool in the biofilm management arsenal.

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