Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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Start date: 2022Subject: search.filters.subject.Ammonia

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    Exploring in vitro production of colonic microbial metabolites from diverse protein sources using human ileal digesta
    (Elsevier Ltd, 2025-12-15) van der Wielen N; Zhang H; Schouten PJC; Meulenbroeks E; Stroebinger N; Hodgkinson SM; Mensink M; Hendriks W; Capuano E
    We explored the relationship between protein fermentation metabolites and ileal digesta composition, using ileal digesta from ileostomates, who ingested nine different protein sources, incubated in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). NH3, short-chain fatty acids, branched-chain fatty acids (BCFA), H2S, tryptophan derivatives, and biogenic amines were measured in proximal and distal colon vessels. The relative changes in most metabolites were positively correlated with their amino acid precursors in ileal digesta. In both colon vessels, the relative change of NH3 was a good predictor for the production of other metabolites. Indole was strongly associated with oxindole, 5-HT, and tryptamine and the sum of Trp metabolites in the distal colon. Per gram ingested protein, zein and whey may produce the highest levels of NH3 and BCFA in the proximal colon and BCFA in the distal colon, whereas whey and pigeon peas may result in the highest levels of H2S.
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    Public response to decarbonisation through alternative shipping fuels
    (Springer Nature, 2023-06-24) Carlisle DP; Feetham PM; Wright M; Teagle D
    Although shipping is the most energy efficient method of transporting trade goods it is held accountable for 2-3% of global greenhouse gas (GHG) emissions. The shipping industry is exploring pathways to carbon-neutral fuels to help eliminate GHG emissions by 2050. To date research on alternative fuels has not considered public opinion; it remains unclear whether the public will support alternative shipping fuels, or whether public opposition might prevent or defer their deployment. To fill this knowledge gap and help the industry and policy makers arrive at publicly acceptable decisions our research examines UK public perceptions of six shipping fuels using a mixed-method approach. Our findings reveal that biofuels and hydrogen are clearly favoured, owing to biofuel’s perceived low risk and hydrogen’s lack of negative by-products. Perceptions of liquid natural gas are somewhat positive, suggesting that it provides an acceptable near-term option while other fuels are developed. Despite lingering stigma, nuclear is preferred over the incumbent heavy fuel oil, though both are perceived negatively. However, the UK public strongly dislike ammonia, perceiving it as unproven, risky, and lacking availability. A third support use of alternative shipping fuels, with support greater from those living near ports - a “yes in my back yard” (YIMBY) effect. The results demonstrate that different alternative fuels are likely to elicit different public reactions as they become more widely known and show how the overall evaluations arise from specific positive or negative associations with each fuel.
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    Copper induces nitrification by ammonia-oxidizing bacteria and archaea in pastoral soils
    (Wiley, 12/12/2022) Matse D; Jeyakumar P; Bishop P; Anderson C
    Copper (Cu) is the main co-factor in the functioning of the ammonia monooxygenase (AMO) enzyme, which is responsible for the first step of ammonia oxidation. We report a greenhouse-based pot experiment that examines the response of ammonia-oxidizing bacteria and archaea (AOB and AOA) to different bioavailable Cu concentrations in three pastoral soils (Recent, Pallic, and Pumice soils) planted with ryegrass (Lolium perenne L.). Five treatments were used: control (no urine and Cu), urine only at 300 mg N kg-1 soil (Cu0), urine + 1 mg Cu kg-1 soil (Cu1), urine + 10 mg Cu kg-1 soil (Cu10), and urine + 100 mg Cu kg-1 soil (Cu100). Pots were destructively sampled at Day 0, 1, 7, 15, and 25 after urine application. The AOB/AOA amoA gene abundance was analyzed by real-time quantitative polymerase chain reaction at Days 1 and 15. The AOB amoA gene abundance increased 10.0- and 22.6-fold in the Recent soil and 2.1- and 2.5-fold in the Pallic soil for the Cu10 compared with Cu0 on Days 1 and 15, respectively. In contrast, the Cu100 was associated with a reduction in AOB amoA gene abundance in the Recent and Pallic soils but not in the Pumice soil. This may be due to the influence of soil cation exchange capacity differences on the bioavailable Cu. Bioavailable Cu in the Recent and Pallic soils influenced nitrification and AOB amoA gene abundance, as evidenced by the strong positive correlation between bioavailable Cu, nitrification, and AOB amoA. However, bioavailable Cu did not influence the nitrification and AOA amoA gene abundance increase.