Influence of Different Substrates in Wetland Soils on Denitrification

Abstract

Different substrates were evaluated to investigate their effect on nitrate removal and denitrifying bacterial community in soils obtained from wetland. Serial batch kinetic tests were conducted on soils obtained from wetland mixed with glucose and sawdust using KNO 3 solution. Column tests were also conducted on soils obtained from wetland mixed with three different substrates (glucose, sawdust, and scoria coated with zero-valent iron) using KNO 3 solution. For the batch tests, the nitrate removal efficiency for soil mixed with glucose was comparable to that for soil mixed with sawdust, but the nitrate removal rate for soil mixed with glucose (23.3 NO 3 − -N mg/L-d) was approximately eight times higher than that for soil mixed with sawdust (2.8 NO 3 − -N mg/L-d). For column tests among soil samples, nitrate removal efficiency was highest in soil mixed with glucose, which is an easily biodegradable carbon source. Removal efficiency increased with increasing incubation time for both soil samples with glucose and sawdust. A phylogenetic analysis based on nitrate reductase gene demonstrated that the different carbon sources affected both the diversity and compositions of the denitrifying bacterial in soil samples.

Expression of denitrification genes in response to a waterlogging event in a Fluvisol and its relationship with large nitrous oxide pulses

“…It was reported previously that C is the limiting factor for bacterial growth in most soils (Aldén et al ., ; Demoling et al ., ). To avoid any bias which may be introduced by addition of C (Goldfarb et al ., ; Hien et al ., ), we did not add any C source to the soil cores. Thus, it is reasonable to see such a result.…”

Influence of Temperature on Denitrification and Microbial Community Structure and Diversity: A Laboratory Study on Nitrate Removal from Groundwater

“…Lina Feng et al [8] found that temperature affects the growth state of microorganisms such as Ulva prolifera and that the structure of enzymes is destroyed and their activity inhibited at excessively high temperatures. Saleema Saleh-Lakha et al [9] found that temperature does not inhibit the transcription of denitrification genes but has different effects on the expression of denitrification genes, and temperature has a significant effect on enzyme activity. Temperature is also the most important factor affecting the growth and reproduction of microorganisms [10,11].…”