The use of zero-valent iron nanoparticles (nZVI) is an emerging application for environmental remediation. In the present work, the effect of mild nZVI conditions (2.5, 10, and 25 mg L⁻¹) on the bacteria biofilm and growth of both planktonic and sessile cells based on a Pseudomonas putida (P. putida) model was studied. Core shell nZVI nanoparticles (25 nm in size) were purchased and characterized. P. putida biofilm was growth in Luria–Bertani (LB) in absence and presence of nZVI at different concentrations, 2.5, 10, and 25 mg L⁻¹ for 7 days. The secretion of exopolysaccharides (EPS), the population of planktonic cells and sessile cells, and biofilm structure were investigated. nZVI did not inhibit planktonic cells growth at all nZVI concentrations, suggesting nZVI as an inert against planktonic cells. More importantly, the EPS production and population of sessile cells in nZVI-biofilm were considerably higher than those in control biofilm. A dense and confluent biofilm structure for nZVI-biofilm was developed even at 2.5 mg L⁻¹ of nZVI concentration, probably to prevent the penetration of nZVI into the biofilm matrix. The present work has revealed that nZVI plays a role in a promotion of biofilm production. Furthermore, a decrease in population of P. putida in nZVI-biofilm was delayed when compared to that in control biofilm. The 1-log reduction was reached at 30 and 60 days for control biofilm and nZVI-biofilm, respectively. In conclusion, nZVI provided a positive action for dense biofilm formation and consequently enhancement of bacteria cell survival.

零价铁纳米粒子 (nZVI) 的使用是一种新兴的环境修复应用。在目前的工作中，基于恶臭假单胞菌( P. putida ) 模型，研究了温和的 nZVI 条件（2.5、10 和 25 mg L ^-1）对细菌生物膜和浮游细胞和固着细胞生长的影响。购买并表征了核壳 nZVI 纳米颗粒（尺寸为 25 nm）。恶臭假单胞菌生物膜在 Luria-Bertani (LB) 中在不存在和存在不同浓度 nZVI（2.5、10 和 25 mg L ^-1）的情况下生长7 天。研究了胞外多糖 (EPS) 的分泌、浮游细胞和无柄细胞的数量以及生物膜结构。nZVI 在所有 nZVI 浓度下均不抑制浮游细胞生长，表明 nZVI 对浮游细胞具有惰性。更重要的是，nZVI 生物膜中的 EPS 产量和固着细胞数量明显高于对照生物膜中的。即使在 2.5 mg L ^-1的 nZVI 浓度下，也为 nZVI 生物膜开发了致密且融合的生物膜结构，这可能是为了防止 nZVI 渗透到生物膜基质中。目前的工作表明，nZVI 在促进生物膜生产中发挥作用。此外，恶臭假单胞菌种群减少与对照生物膜相比，nZVI-生物膜中的延迟。对照生物膜和 nZVI 生物膜分别在 30 天和 60 天达到 1-log 减少。总之，nZVI 为致密的生物膜形成提供了积极的作用，从而提高了细菌细胞的存活率。