MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China.
MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, China
Appl Environ Microbiol. 2019 Sep 17;85(19). doi: 10.1128/AEM.01196-19. Print 2019 Oct 1.
Bacterial consortia are among the most basic units in the biodegradation of environmental pollutants. Pollutant-degrading strains frequently encounter different types of environmental stresses and must be able to survive with other bacteria present in the polluted environments. In this study, we proposed a noncontact interaction mode between a tetrahydrofuran (THF)-degrading strain, YYL, and a non-THF-degrading strain, MLY1. The metabolic interaction mechanism between strains YYL and MLY1 was explored through physiological and molecular studies and was further supported by the metabolic response profile of strain YYL, both monocultured and cocultured with strain MLY1 at the optimal pH (pH 8.3) and under pH stress (pH 7.0), through a liquid chromatography-mass spectrometry-based metabolomic analysis. The results suggested that the coculture system resists pH stress in three ways: (i) strain MLY1 utilized acid metabolites and impacted the proportion of glutamine, resulting in an elevated intracellular pH of the system; (ii) strain MLY1 had the ability to degrade intermediates, thus alleviating the product inhibition of strain YYL; and (iii) strain MLY1 produced some essential micronutrients for strain YYL to aid the growth of this strain under pH stress, while strain YYL produced THF degradation intermediates for strain MLY1 as major nutrients. In addition, a metabolite cross-feeding interaction with respect to pollutant biodegradation is discussed. species have been discovered in diverse environmental niches and can degrade numerous recalcitrant toxic pollutants. However, the pollutant degradation efficiency of these strains is severely reduced due to the complexity of environmental conditions and limitations in the growth of the pollutant-degrading microorganism. In our study, strain MLY1 exhibited strong stress resistance to adapt to various environments and improved the THF degradation efficiency of YYL by a metabolic cross-feeding interaction style to relieve the pH stress. These findings suggest that metabolite cross-feeding occurred in a complementary manner, allowing a pollutant-degrading strain to collaborate with a nondegrading strain in the biodegradation of various recalcitrant compounds. The study of metabolic exchanges is crucial to elucidate mechanisms by which degrading and symbiotic bacteria interact to survive environmental stress.
细菌群落是环境污染物生物降解中最基本的单位之一。污染物降解菌株经常遇到不同类型的环境压力，必须能够与污染环境中存在的其他细菌共存。在本研究中，我们提出了一种四氢呋喃（THF）降解菌株 YYL 与非 THF 降解菌株 MLY1 之间的非接触相互作用模式。通过生理和分子研究探讨了菌株 YYL 和 MLY1 之间的代谢相互作用机制，并通过代谢组学分析进一步支持了在最佳 pH（pH 8.3）和 pH 应激（pH 7.0）下，单独培养和共培养菌株 YYL 时菌株 YYL 的代谢响应谱。结果表明，共培养系统通过三种方式抵抗 pH 应激：（i）菌株 MLY1 利用酸代谢物并影响谷氨酰胺的比例，从而提高系统的细胞内 pH；（ii）菌株 MLY1 具有降解中间产物的能力，从而缓解了菌株 YYL 的产物抑制；（iii）菌株 MLY1 产生一些对菌株 YYL 生长至关重要的必需微量元素，使该菌株在 pH 应激下生长，而菌株 YYL 则产生 THF 降解中间产物作为菌株 MLY1 的主要营养物质。此外，还讨论了与污染物生物降解有关的代谢物交叉喂养相互作用。 在各种环境小生境中已经发现了许多不同的细菌物种，它们可以降解许多难降解的有毒污染物。然而，由于环境条件的复杂性和污染物降解微生物生长的限制，这些菌株的污染物降解效率严重降低。在我们的研究中，菌株 MLY1 表现出很强的抗应激能力，以适应各种环境，并通过代谢交叉喂养相互作用提高了 YYL 的 THF 降解效率，从而缓解了 pH 应激。这些发现表明，代谢物交叉喂养以互补的方式发生，允许污染物降解菌株与非降解菌株在各种难降解化合物的生物降解中合作。代谢交换的研究对于阐明降解菌和共生菌如何相互作用以应对环境压力的机制至关重要。
