Microbial community engineering aims for enrichment of a specific microbial trait by imposing specific cultivation conditions. This work demonstrates that things may be more complicated than typically presumed and that microbial competition can be affected by seemingly insignificant variables, like in this case the type of acid used for pH control. Aerobic bioreactors pulse fed with acetate operated with hydrochloric acid resulted in the enrichment of Plasticicumulans acidivorans, and changing the pH controlling agent to sulfuric acid shifted the community towards Zoogloea sp. Further research demonstrated that the change in community structure was not directly caused by the change in acid used for pH control, but resulted from the difference in corrosive strength of both acids and the related iron leaching from the bioreactor piping. Neither system was iron deficient, suggesting that the biological availability of iron is affected by the leaching process. Our results demonstrate that microbial competition and process development can be affected dramatically by secondary factors related to nutrient supply and bioavailability, and is way more complex than generally assumed in a single carbon substrate limited process.

中文翻译：

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似乎琐碎的次要因素可能决定了微生物竞争：关于通过腐蚀补充铁的影响的警示性故事

微生物群落工程旨在通过施加特定的栽培条件来丰富特定的微生物性状。这项工作表明，事情可能比通常假定的要复杂，微生物竞争可能受到看似无关紧要的变量的影响，例如在这种情况下，用于控制pH的酸的类型。脉冲喂乙酸的好氧生物反应器用盐酸处理导致嗜酸塑料富集，将pH控制剂改变为硫酸使群落向菌藻转移。。进一步的研究表明，群落结构的变化并非直接由用于控制pH的酸的变化引起，而是由于两种酸的腐蚀强度不同以及从生物反应器管道中浸出的相关铁而引起的。两种系统都不缺铁，表明浸出过程会影响铁的生物利用度。我们的结果表明，微生物的竞争和过程的发展会受到与养分供应和生物利用度有关的次要因素的显着影响，并且比单一碳底物受限过程中普遍假设的复杂得多。