A unique bacteriohopanetetrol stereoisomer of marine anammox

Abstract

Anaerobic ammonium oxidation (anammox) is a significant process for bioavailable nitrogen removal from marine systems. A bacteriohopanetetrol (BHT) isomer, with unknown stereochemistry, eluting later than BHT using high performance liquid chromatography (HPLC), was detected in ‘Ca. Scalindua profunda’ and proposed as a biomarker for anammox in marine paleo-environments. Four non-marine, non-anammox genera also produce late-eluting BHT stereoisomers. Of these, the stereochemistry in Acetobacter pasteurianus, Komagataeibacter xylinus and Frankia sp. was shown to be 17β, 21β(H), 22R, 32R, 33R, 34R (BHT-34R), while the stereochemistry of the late-eluting BHT in Methylocella palustris was unknown. We studied the BHT distributions and stereochemistry of these known BHT isomer producers and of previously unscreened marine (‘Ca. Scalindua brodeae’) and freshwater (‘Ca. Brocadia sp.’) anammox species and genera using HPLC and gas chromatographic (GC) analysis of acetylated BHTs and ultra high performance liquid chromatography (UHPLC)-High Resolution Mass Spectrometry (HRMS) analysis of non-acetylated BHTs. The 34R stereochemistry was confirmed for the BHT isomers in Ca. Brocadia sp., and Methylocella palustris. However, ‘Ca. Scalindua sp.’ synthesise a stereochemically distinct BHT isomer, with a still unconfirmed stereochemistry (BHT-x). ‘Ca. Kuenenia sp.’ was confirmed not to produce any late-eluting BHT stereoisomers. Only GC analysis of acetylated BHT and UHPLC analysis of non-acetylated BHT distinguished between late-eluting BHT isomers. Acetylated BHT-x and BHT-34R co-elute by HPLC. As BHT-x is so far only known to be produced by ‘Ca. Scalindua spp.’, it may be applied as a biomarker for marine anammox. As ‘Ca. Brocadia sp.’ produces BHT-34R, this BHT isomer is a potential, albeit less specific, biomarker for anammox in non-marine settings.

Bacterial and archaeal lipids trace chemo(auto)trophy along the redoxcline in Vancouver Island fjords

“…It is therefore likely that anammox bacteria also play a prominent role in the N cycle of the analogous environments of Effingham Inlet and Deer Bay. BHT‐x, the BHT isomer exclusively produced by anammox bacteria (Schwartz Narbonne et al., 2020), can be used to trace this process in our water column samples. While our chromatographic method did not resolve BHT‐II and BHT‐x (Schwartz Narbonne et al., 2020), it is likely that the low isomer abundances detected above ∼30–40 μ m O 2 (in the surface water samples) reflect “background” BHT‐II produced by other bacteria, and the substantially higher isomer abundances below this threshold could then be attributed to an additional contribution of BHT‐x to “background” BHT‐II (Figure 7).…”

“…BHT‐x, the BHT isomer exclusively produced by anammox bacteria (Schwartz Narbonne et al., 2020), can be used to trace this process in our water column samples. While our chromatographic method did not resolve BHT‐II and BHT‐x (Schwartz Narbonne et al., 2020), it is likely that the low isomer abundances detected above ∼30–40 μ m O 2 (in the surface water samples) reflect “background” BHT‐II produced by other bacteria, and the substantially higher isomer abundances below this threshold could then be attributed to an additional contribution of BHT‐x to “background” BHT‐II (Figure 7). Kalvelage et al., (2011) report the upper limit for anammox to be ∼20 μ m O 2 , which agrees well with the half‐inhibition concentration (IC 50 ) for anammox between 1 and ∼10 μ m O 2 determined by Bristow et al., (2016).…”

“…Kuenenia stuttgartiensis” and “ Ca . Brocadia spp.” enrichment cultures (Rush et al., 2014; Schwartz Narbonne et al., 2020) in addition to its δ 13 C‐depleted signatures in cultures and the environment (Hemingway et al., 2018; Lengger et al., 2019). However, trace amounts of BHT isomer have also been found in oxic marine environments (Kusch et al., 2018, 2019; Matys et al., 2017).…”

“…However, trace amounts of BHT isomer have also been found in oxic marine environments (Kusch et al., 2018, 2019; Matys et al., 2017). This conundrum has now been resolved by a new GC method that revealed the presence of two BHT isomers (BHT‐II and BHT‐x) that otherwise co‐elute during standard HPLC analysis, of which BHT‐x is now considered to be the more robust anammox biomarker (Schwartz Narbonne et al., 2020). Other BHPs such as methylcarbamate‐substituted amino‐BHPs and aminopentol have primarily been identified in methane‐oxidizing bacteria (Rush et al., 2016) and can, thus, be linked to aerobic methanotrophy.…”

δ13C compositions of bacteriohopanetrol isomers reveal bacterial processes involved in the carbon cycle

“…While BHT-17β(H), 21β(H), 22R, 32R, 33R, 34S (BHT-34S) is ubiquitous in the environment, its 34R stereoisomer (BHT-17β(H), 21β(H), 22R, 32R, 33R, 34R; BHT-34R) has only five known producers: the freshwater anammox genera 'Candidatus Brocadia', the aerobic acidic peatland methanotroph Methylocella palustris, the nitrogen-fixing aerobic bacteria Frankia spp., and the aerobic acetic acid-producing bacteria Acetobacter pasteurianus and Komagataeibacter xylinus. BHT-x-another BHT isomer of unknown stereochemistry-has only one known producer, the marine anammox bacteria 'Candidatus Scalindua' (Schwartz-Narbonne et al, 2020). The occurrence and extent of these…”