Lin Bin, Westerhoff Hans V, Röling Wilfred F M
Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands.
Environ Microbiol. 2009 Sep;11(9):2425-33. doi: 10.1111/j.1462-2920.2009.01971.x. Epub 2009 Jul 22.
Geobacteraceae dominate many iron-reducing subsurface environments and are associated with biodegradation of organic pollutants. In order to enhance the understanding of the environmental role played by Geobacteraceae, the physiology of Geobacter metallireducens was investigated at the low growth rates found in its subsurface habitat. Cultivation in retentostats (a continuous culturing device with biomass retention) under electron acceptor and electron donor limitation enabled growth rates as low as 0.0008 h(-1). The maximum growth yield was between 0.05 and 0.09 C-mol biomass per C-mol acetate and comparable to that observed in batch experiments. Maintenance energy demand is among the lowest reported for heterotrophic bacteria, under both acetate and AQDS limitation. The cells were able to use alternative electron acceptors directly, without requiring de novo protein synthesis. We discuss how the extremely low maintenance energy demand and the ability to readily use alternative electron acceptors may help Geobacter species to become ubiquitous and dominant microorganisms in many iron-reducing subsurface settings.
地杆菌科在许多地下铁还原环境中占主导地位，并与有机污染物的生物降解有关。为了增进对地杆菌科所发挥的环境作用的理解，研究了金属还原地杆菌在其地下栖息地发现的低生长速率下的生理学特性。在电子受体和电子供体受限的恒化器（一种具有生物量保留功能的连续培养装置）中培养，可实现低至0.0008 h⁻¹的生长速率。最大生长产量为每C摩尔乙酸产生0.05至0.09 C摩尔生物量，与分批实验中观察到的产量相当。在乙酸盐和蒽醌二磺酸盐受限的情况下，维持能量需求是报道的异养细菌中最低的之一。细胞能够直接使用替代电子受体，而无需从头合成蛋白质。我们讨论了极低的维持能量需求以及易于使用替代电子受体的能力如何可能帮助地杆菌属物种在许多地下铁还原环境中成为普遍存在且占主导地位的微生物。
