Appl Environ Microbiol. 1995 Oct;61(10):3667-75. doi: 10.1128/aem.61.10.3667-3675.1995.
The capacity to form acetate from endogenous matter was a common property of diverse forest soils when incubated under anaerobic conditions. At 15 to 20(deg)C, acetate synthesis occurred without appreciable delay when forest soils were incubated as buffered suspensions or in microcosms at various percentages of their maximum water holding capacity. Rates for acetate formation with soil suspensions ranged from 35 to 220 (mu)g of acetate per g (dry weight) of soil per 24 h, and maximal acetate concentrations obtained in soil suspensions were two- to threefold greater than those obtained with soil microcosms at the average water holding capacity of the soil. Cellobiose degradation in soil suspensions yielded H(inf2) as a transient product. Under anaerobic conditions, supplemental H(inf2) and CO(inf2) were directed towards the acetogenic synthesis of acetate, and enrichments yielded a syringate-H(inf2)-consuming acetogenic consortium. At in situ temperatures, acetate was a relatively stable anaerobic end product; however, extended incubation periods induced acetoclastic methanogenesis and sulfate reduction. Higher mesophilic and thermophilic temperatures greatly enhanced the capacity of soils to form methane. Although methanogenic and sulfate-reducing activities under in situ-relevant conditions were negligible, these findings nonetheless demonstrated the occurrence of methanogens and sulfate-reducing bacteria in these aerated terrestrial soils. In contrast to the protracted stability of acetate under anaerobic conditions at 15 to 20(deg)C with unsupplemented soils, acetate formed by forest soils was rapidly consumed in the presence of oxygen and nitrate, and substrate-product stoichiometries indicated that acetate turnover was coupled to oxygen-dependent respiration and denitrification. The collective results suggest that acetate formed under anaerobic conditions might constitute a trophic link between anaerobic and aerobic processes in forest soils.
在厌氧条件下培养时，从内源性物质形成乙酸盐是各种森林土壤的共同特性。在 15 到 20°C 下，当森林土壤作为缓冲悬浮液或在不同最大持水能力百分比的微宇宙中孵育时，乙酸盐合成没有明显延迟。土壤悬浮液中乙酸盐形成的速率范围为每 24 小时每克（干重）土壤 35 到 220 (mu)g 乙酸盐，并且在土壤悬浮液中获得的最大乙酸盐浓度比在土壤微宇宙中在土壤的平均持水能力下获得的浓度高两到三倍。在土壤悬浮液中，纤维二糖降解产生 H(inf2)作为瞬态产物。在厌氧条件下，补充的 H(inf2) 和 CO(inf2) 被引导用于产乙酸菌的乙酸盐合成，并且富集物产生了消耗丁香酸盐的产乙酸菌联合体。在原位温度下，乙酸盐是一种相对稳定的厌氧末端产物；然而，延长的孵育期会诱导乙酸营养型甲烷生成和硫酸盐还原。较高的中温性和高温性大大增强了土壤形成甲烷的能力。尽管在与原位相关的条件下，甲烷生成和硫酸盐还原活性可以忽略不计，但这些发现仍然表明在这些通气的陆地土壤中存在甲烷生成菌和硫酸盐还原菌。与在 15 到 20°C 下无补充土壤的情况下，在厌氧条件下乙酸盐的延长稳定性形成形成鲜明对比的是，在氧气和硝酸盐存在的情况下，森林土壤形成的乙酸盐会迅速消耗，并且底物-产物化学计量学表明乙酸盐的周转与依赖氧气的呼吸和反硝化作用有关。总的来说，这些结果表明，在厌氧条件下形成的乙酸盐可能构成森林土壤中厌氧和有氧过程之间的营养联系。
