Carbon and energy utilization in microbial cell extracts from soil

作者：Milan Varsadiya, Fatemeh Dehghani, Shiyue Yang, Еvgenia Blagodatskaya, Thomas Maskow, Dimitri V. Meier, Tillmann Lueders · 发表于：European Journal of Soil Biology · 年份：2025 · DOI：10.1016/j.ejsobi.2025.103713 · 被引用次数：4 · 研究领域：Biofuel production and bioconversion、Anaerobic Digestion and Biogas Production、Soil Carbon and Nitrogen Dynamics

Microbial carbon use efficiency (CUE), the ratio of carbon retained in biomass vs. total C uptake, is central to our understanding of organic C turnover in soil. A precise quantification of CUE in soils can be challenging, given the considerable analytical uncertainties of organic and inorganic C backgrounds. At the same time, CUE measured for model pure cultures will be distinct from a diverse microbiota in soil. As a proxy between laboratory cultures and complex soil microbiomes, we tested soil-free microbial cell extracts (SFCE) to unravel patterns of C utilization in soil-derived microbiomes of reduced complexity. For this, we have revisited and optimized established protocols to extract microbial cells from agricultural soil via Nycodenz density centrifugation. The total extracted cells were quantified, accounting for up to ∼3.5 × 10 7 cells g −1 soil and representing ∼12.5 % of the original soil microbiome. The diversity of microbes in SFCE, while consistently reduced compared to soil, still retained a surprisingly high proportion of the original soil microbiome, with ASVs recovered from 21 phyla. We then inferred CUE from calorespirometric measurements (metabolic heat flow and CO 2 production) to compare values between SFCE and intact soil. Both were amended with substrates (glucose, glutamine, and glycerol) of different C and N content, and C oxidation state (NOSC). SFCE showed CUE values principally comparable to that of the intact soil, but with substrate-specific d...