Distribution of Nitrosomonas europaea and Paracoccus denitrificans Immobilized in Tubular Polymeric Gel for Nitrogen Removal

Abstract

To improve the cooperative removal of nitrogen by Nitrosomonas europaea and Paracoccus denitrificans, we controlled their distribution in a tubular gel. When ethanol was supplied inside the tubular gel as an electron donor, their distributions overlapped in the external region of the gel. By changing the electron donor from ethanol to gaseous hydrogen, the distribution of P. denitrificans shifted to the inside of the tube and was separated from that of N. europaea. The separation resulted in an increase of the oxidation rate of ammonia by 25%.

Biofilm stratification during simultaneous nitrification and denitrification (SND) at a biocathode

“…Similar results were also obtained on other disks observed. This supports a scenario in which nitrifying organisms deplete the oxygen in the outer layers of the biofilm, thus creating low DO conditions in the lower parts of the biofilm that allowed for simultaneous aerobic and anaerobic respiration, as already reported previously (Munch et al, 1996;Pochana and Keller, 1999;Uemoto and Saiki, 2000). The availability of nutrients plays an important role in biofilm formation as microorganisms position themselves according to the presence of nutrient gradients and in the attempt to protect against harsh environmental conditions.…”

“…The availability of nutrients plays an important role in biofilm formation as microorganisms position themselves according to the presence of nutrient gradients and in the attempt to protect against harsh environmental conditions. Uemoto and Saiki (2000) achieved the separation of Nitrosomonas europaea and Paracoccus denitrificans immobilized in a tubular polymeric gel by providing hydrogen as electron donor in the inside of the tube whereas ammonia and oxygen were available in the liquid bulk. As a result, N. europaea concentrated in the outer region of the gel matrix, while the distribution of P. denitrificans shifted towards the inside of the tubes, remarking a clear separation between the two colonies.…”

Denitrification and ammonia oxidation by Nitrosomonas europaea wild-type, and NirK- and NorB-deficient mutants

“…At higher redox potentials a hydrogen-dependent denitrification activity of Nsm. europaea was not observed (Uemoto & Saiki, 2000).…”

Nitrate removal from the effluent of a fertilizer industry using a bioreactor packed with immobilized cells of Pseudomonas stutzeri and Comamonas testosteroni

“…A number of studies (Santos et al 1993;Uemoto & Saiki 1996Kesseri et al 2002) have shown an effective denitrification with attached and immobilized cells on a different supporting matrix. Uemoto & Saiki (2000) had achieved nitrogen removal from wastewater by use of a tubular gel containing Nitrosomonas europaea and Paracoccus denitrificans. Gas-permeable silicone tubing was used as the basis of a bioreactor for autotrophic denitrification (Ho et al 2001).…”