Groundwater Nitrate Removal Performance of Selected Pseudomonas Strains Carrying nosZ Gene in Aerobic Granular Sequential Batch Reactors
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AuthorHurtado Martínez, Miguel; Muñoz Palazón, Barbara; González Martínez, Alejandro; Manzanera Ruiz, Maximino Enrique; González López, Jesús Juan
PseudomonasGranular biomassSequential batch reactorNitrate-polluted groundwaterHeterotrophic denitrification
Hurtado-Martinez, M.; Muñoz-Palazon, B.; GonzalezMartinez, A.; Manzanera, M.; Gonzalez-Lopez, J. Groundwater Nitrate Removal Performance of Selected Pseudomonas Strains Carrying nosZ Gene in Aerobic Granular Sequential Batch Reactors. Water 2021, 13, 1119. https:// doi.org/10.3390/w13081119
SponsorshipLIFE16 ENV/ES/000196 project
Four granular sequencing batch reactors (GSBRs) were inoculated with four denitrifying Pseudomonas strains carrying nosZ to study the process of granule formation, the operational conditions of the bioreactors, and the carbon concentration needed for nitrate removal. The selected Pseudomonas strains were P. stutzeri I1, P. fluorescens 376, P. denitrificans Z1, and P. fluorescens PSC26, previously reported as denitrifying microorganisms carrying the nosZ gene. Pseudomonas denitrificans Z1 produced fluffy, low-density granules, with a decantation speed below 10 m h−1 . However, P. fluorescens PSC26, P. stutzeri I1, and P. fluorescens 376 formed stable granules, with mean size from 7 to 15 mm, related to the strain and carbon concentration. P. stutzeri I1 and P. fluorescens 376 removed nitrate efficiently with a ratio in the range of 96%, depending on the source and concentration of organic matter. Therefore, the findings suggest that the inoculation of GSBR systems with denitrifying strains of Pseudomonas spp. containing the nosZ gene enables the formation of stable granules, the efficient removal of nitrate, and the transformation of nitrate into nitrogen gas, a result of considerable environmental interest to avoid the generation of nitrous oxide.