MyMedR

Displaying all 4 publications

Abstract:

Sort:

Effect of external hydrazine addition on anammox reactor start-up time

Ganesan S, Vadivelu VM

Chemosphere, 2019 May;223:668-674.
PMID: 30802832 DOI: 10.1016/j.chemosphere.2019.02.104

Hydrazine is an intermediate product of the anaerobic ammonium oxidation (Anammox) process where both ammonium and nitrite in wastewater are converted to nitrogen gas by bacteria. In this study the effect of external hydrazine addition (5, 10, 15, and 20 mg/L) on the start-up period of the Anammox process was studied using sequencing batch reactors (SBRs). The SBR with an addition of 10 mg/L hydrazine took only 7 weeks to stabilize and achieve the maximum removal of ammonium and nitrite, whereas the SBR without the addition of hydrazine took 12 weeks. The amount of Heme C extracted from the biomass indicated that externally added hydrazine accelerated the growth of Anammox bacteria and reduced the release of nitrous oxide gas from the reactors.

Matched MeSH terms: Nitrous Oxide/metabolism
Fulltext Greenhouse gas emissions resulting from conversion of peat swamp forest to oil palm plantation

Cooper HV, Evers S, Aplin P, Crout N, Dahalan MPB, Sjogersten S

Nat Commun, 2020 01 21;11(1):407.
PMID: 31964892 DOI: 10.1038/s41467-020-14298-w

Conversion of tropical peat swamp forest to drainage-based agriculture alters greenhouse gas (GHG) production, but the magnitude of these changes remains highly uncertain. Current emissions factors for oil palm grown on drained peat do not account for temporal variation over the plantation cycle and only consider CO2 emissions. Here, we present direct measurements of GHGs emitted during the conversion from peat swamp forest to oil palm plantation, accounting for CH4 and N2O as well as CO2. Our results demonstrate that emissions factors for converted peat swamp forest is in the range 70-117 t CO2 eq ha-1 yr-1 (95% confidence interval, CI), with CO2 and N2O responsible for ca. 60 and ca. 40% of this value, respectively. These GHG emissions suggest that conversion of Southeast Asian peat swamp forest is contributing between 16.6 and 27.9% (95% CI) of combined total national GHG emissions from Malaysia and Indonesia or 0.44 and 0.74% (95% CI) of annual global emissions.

Matched MeSH terms: Nitrous Oxide/metabolism
Fulltext Antidiarrhoeal investigation of Apium leptophyllum (Pers.) by modulation of Na+K+ATPase, nitrous oxide and intestinal transit in rats

Sahoo HB, Sagar R, Kumar A, Bhaiji A, Bhattamishra SK

Biomed J, 2016 Dec;39(6):376-381.
PMID: 28043416 DOI: 10.1016/j.bj.2016.11.003

BACKGROUND: Apium leptophyllum (Pers.) is an annual herb with traditional appreciation for various pharmacological properties; however, the scientific information on this herb is insufficient. The aim of the present investigation was undertaken to evaluate flavonoidal fraction of A. leptophyllum fruit (FFALF) against diarrhoea on albino rats.
METHODS: The antidiarrhoeal study was conducted by castor oil induce diarrhoea, prostaglandin E2 (PGE2) induced enteropooling and intestinal transit by charcoal meal test. The rats were divided into five groups (six/group). Group I served as control and received orally 2% acacia suspension; Group II served as standard and received orally loperamide (3 mg/kg) or atropine sulphate (5 mg/kg); Group III, IV and V served as test groups and received the FFALF at doses of 5, 10 and 20 mg/kg orally, respectively.
RESULTS: In castor oil-induced diarrhoeal model, the FFALF significantly (p

Matched MeSH terms: Nitrous Oxide/metabolism
Fulltext Temporal dynamics of soil microbial C and N cycles with GHG fluxes in the transition from tropical peatland forest to oil palm plantation

Midot F, Goh KM, Liew KJ, Lau SYL, Espenberg M, Mander Ü, et al.

Appl Environ Microbiol, 2025 Jan 31;91(1):e0198624.
PMID: 39714193 DOI: 10.1128/aem.01986-24

Tropical peatlands significantly influence local and global carbon and nitrogen cycles, yet they face growing pressure from anthropogenic activities. Land use changes, such as peatland forests conversion to oil palm plantations, affect the soil microbiome and greenhouse gas (GHG) emissions. However, the temporal dynamics of microbial community changes and their role as GHG indicators are not well understood. This study examines the dynamics of peat chemistry, soil microbial communities, and GHG emissions from 2016 to 2020 in a logged-over secondary peat swamp forest in Sarawak, Malaysia, which transitioned to an oil palm plantation. This study focuses on changes in genetic composition governing plant litter degradation, methane (CH4), and nitrous oxide (N2O) fluxes. Soil CO2 emission increased (doubling from approximately 200 mg C m-2 h-1), while CH4 emissions decreased (from 200 µg C m-2 h-1 to slightly negative) following land use changes. The N2O emissions in the oil palm plantation reached approximately 1,510 µg N m-2 h-1, significantly higher than previous land uses. The CH4 fluxes were driven by groundwater table, humification levels, and C:N ratio, with Methanomicrobia populations dominating methanogenesis and Methylocystis as the main CH4 oxidizer. The N2O fluxes correlated with groundwater table, total nitrogen, and C:N ratio with dominant nirK-type denitrifiers (13-fold nir to nosZ) and a minor role by nitrification (a threefold increase in amoA) in the plantation. Proteobacteria and Acidobacteria encoding incomplete denitrification genes potentially impact N2O emissions. These findings highlighted complex interactions between microbial communities and environmental factors influencing GHG fluxes in altered tropical peatland ecosystems.IMPORTANCETropical peatlands are carbon-rich environments that release significant amounts of greenhouse gases when drained or disturbed. This study assesses the impact of land use change on a secondary tropical peat swamp forest site converted into an oil palm plantation. The transformation lowered groundwater levels and changed soil properties. Consequently, the oil palm plantation site released higher carbon dioxide and nitrous oxide compared to previous land uses. As microbial communities play crucial roles in carbon and nitrogen cycles, this study identified environmental factors associated with microbial diversity, including genes and specific microbial groups related to nitrous oxide and methane emissions. Understanding the factors driving microbial composition shifts and greenhouse gas emissions in tropical peatlands provides baseline information to potentially mitigate environmental consequences of land use change, leading to a broader impact on climate change mitigation efforts and proper land management practices.

Matched MeSH terms: Nitrous Oxide/metabolism