Effect of Mixed Electron Donors on Autotrophic Denitrification by Pseudomonas sp. SZF15

Abstract

In this study, mixed electron donors of Mn(II) and Fe(II) were tested for their effects on autotrophic denitrification. The denitrification performance based on various Mn(II)/Fe(II) molar ratios was assessed via batch experiments conducted under different conditions of temperature, pH, and electron donor/electron acceptor molar ratios. Complete nitrate removal was found at high Mn(II)/Fe(II) molar ratios, 30 °C, pH 7.0, and an electron donor/electron acceptor molar ratio of 3.00. Furthermore, we assessed the expression of nirS through amplification approaches and determined N 2 levels by gas chromatography. Our results demonstrated that mixed electron donors are efficient for autotrophic denitrification, and strain SZF15 is a suitable candidate for the simultaneous removal of nitrogen, Fe(II), and Mn(II) in groundwater treatment. The present work will benefit the development of autotrophic denitrification technology.

Bacteria-supported iron scraps for the removal of nitrate from low carbon-to-nitrogen ratio wastewater

“…As a promising alternative of heterotrophic denitrication, autotrophic denitrication, using inorganic compounds including hydrogen gas, ferrous iron and reduced sulfur compounds as electron donor, is increasingly being studied in recent years. [17][18][19][20][21][22][23] Autotrophic denitrication especially hydrogen-based one (hydrogenotrophic denitrication) is desirable because of its nontoxicity and low biomass. 24 During the hydrogenotrophic denitrication process, hydrogen is used by hydrogenotrophic denitrifying bacteria as electron donor, and inorganic carbon, such as carbon dioxide and bicarbonate, is used as carbon source.…”