Increased acid resistance of the archaeon,<i>Metallosphaera sedula</i>by adaptive laboratory evolution

Ai, Chenbing; McCarthy, Samuel; Eckrich, Valerie; Rudrappa, Deepak; Qiu, Guanzhou; Blum, Paul H.

doi:10.1007/s10295-016-1812-0

Cited by 27 publications

(13 citation statements)

References 69 publications

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“…Since the expression of functional genes of either single strain or microbial consortium were altered by various physicochemical parameters [49][50][51][52]. Therefore, it is necessary to compare the profiles of expressed functional genes under different simulated temperature variation by metatranscriptomic analysis in near future.…”

Section: The Variation Of Key Enzymes In Nitrogen Metabolic Pathwaysmentioning

confidence: 99%

Metagenomic Insights into the Effects of Seasonal Temperature Variation on the Activities of Activated Sludge

Zhang

Zhou

et al. 2019

Microorganisms

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It is well acknowledged that the activities of activated sludge (AS) are influenced by seasonal temperature variation. However, the underlying mechanisms remain largely unknown. Here, the activities of activated sludge under three simulated temperature variation trends were compared in lab-scale. The TN, HN3-H, and COD removal activities of activated sludge were improved as temperature elevated from 20 °C to 35 °C. While, the TN, HN3-H, COD and total phosphorus removal activities of activated sludge were inhibited as temperature declined from 20 °C to 5 °C. Both the extracellular polymer substances (EPS) composition (e.g., total amount, PS, PN and DNA) and sludge index of activated sludge were altered by simulated seasonal temperature variation. The variation of microbial community structures and the functional potentials of activated sludge were further explored by metagenomics. Proteobacteria, Actinobacteria, Acidobacteria and Bacteroidetes were the dominant phyla for each activated sludge sample under different temperatures. However, the predominant genera of activated sludge were significantly modulated by simulated temperature variation. The functional genes encoding enzymes for nitrogen metabolism in microorganisms were analyzed. The enzyme genes related to ammonification had the highest abundance despite the changing temperature, especially for gene encoding glutamine synthetase. With the temperature raising from 20 °C to 35 °C. The abundance of amoCAB genes encoding ammonia monooxygenase (EC:1.14.99.39) increased by 305.8%. Meanwhile, all the enzyme genes associate with denitrification were reduced. As the temperature declined from 20 °C to 5 °C, the abundance of enzyme genes related to nitrogen metabolism were raised except for carbamate kinase (EC:2.7.2.2), glutamate dehydrogenase (EC:1.4.1.3), glutamine synthetase (EC:6.3.1.2). Metagenomic data indicate that succession of the dominant genera in microbial community structure is, to some extent, beneficial to maintain the functional stability of activated sludge under the temperature variation within a certain temperature range. This study provides novel insights into the effects of seasonal temperature variation on the activities of activated sludge.

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Section: The Variation Of Key Enzymes In Nitrogen Metabolic Pathwaysmentioning

confidence: 99%

Metagenomic Insights into the Effects of Seasonal Temperature Variation on the Activities of Activated Sludge

Zhang

Zhou

et al. 2019

Microorganisms

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“…Whole-cell adaptive laboratory evolution (ALE) schemes have been effective at increasing growth rates and tolerances. [16][17][18][19][20] However, these approaches are prima facie limited to growthbased selection without an alternative mode of screening or selection. Some recent evolutionary strategies exploit a selectable feature of the compound of interest [21,22] or rely on an antimetabolite strategy to link the phenotype to growth.…”

Section: Introductionmentioning

confidence: 99%

Biosensor‐Enabled Directed Evolution to Improve Muconic Acid Production in Saccharomyces cerevisiae

Leavitt

Wagner

et al. 2017

Biotechnology Journal

108

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Muconic acid is a valuable platform chemical with potential applications in the production of polymers such as nylon and polyethylene terephthalate (PET). The conjugate base, muconate, has been previously biosynthesized in the bacterial host Escherichia coli. Likewise, previous significant pathway engineering lead to the first reported instance of rationally engineered production of muconic acid in the yeast Saccharomyces cerevisiae. To further increase muconic acid production in this host, a combined adaptive laboratory evolution (ALE) strategy and rational metabolic engineering is employed. To this end, a biosensor module that responds to the endogenous aromatic amino acid (AAA) as a surrogate for pathway flux is adapted. Following two rounds of ALE coupled with an anti-metabolite feeding strategy, the strains with improved AAA pathway flux is isolated. Next, it is demonstrated that this increased flux can be redirected into the composite muconic acid pathway with a threefold increase in the total titer of the composite pathway compared to our previously engineered strain. Finally, a truncation of the penta-functional ARO1 protein is complemented and overexpress an endogenous aromatic decarboxylase to establish a final strain capable of producing 0.5 g L muconic acid in shake flasks and 2.1 g L in a fed-batch bioreactor with a yield of 12.9 mg muconic acid/g glucose at the rate of 9.0 mg h . This value represents the highest titer of muconic acid reported to date in S. cerevisiae, in addition to the highest reported titer of a shikimate pathway derivative in this host.

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“…These 78 strains showed mutations in amino acid transporters, as well as upregulation of membrane 79 biosynthesis and oxidative stress response. In Metallosphaera sedula, serial passage led to a pH 80 0.9-adapted strain with four mutations, one of which is an amino-acid/polyamine transporter 81 (29). These findings are intriguing, given the role of amino-acid transport and catabolism in 82 extreme-acid survival of bacteria (24,25).…”

Section: Importance 36mentioning

confidence: 99%

Acid Experimental Evolution of the Extremely Halophilic Archaeon Halobacterium sp. NRC-1 Selects Mutations Affecting Arginine Transport and Catabolism

Kunka

Griffith

Holdener

et al. 2019

Preprint

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16Halobacterium sp. NRC-1 (NRC-1) is an extremely halophilic archaeon that is well 17 adapted to multiple stressors such as UV, ionizing radiation, and arsenic exposure. We conducted 18 experimental evolution of NRC-1 under acid and iron stress to expand the stressors. NRC-1 was 19 serially cultured in CM+ medium modified by four stress conditions, with four evolving 20 populations per condition. At 500 generations the conditions were: optimal pH (pH 7.5), acid 21 stress (pH 6.3), iron stress (600 μM ferrous sulfate, pH 7.5), and acid plus iron stress (600 μM 22

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Increased acid resistance of the archaeon,Metallosphaera sedulaby adaptive laboratory evolution

Cited by 27 publications

References 69 publications

Metagenomic Insights into the Effects of Seasonal Temperature Variation on the Activities of Activated Sludge

Metagenomic Insights into the Effects of Seasonal Temperature Variation on the Activities of Activated Sludge

Biosensor‐Enabled Directed Evolution to Improve Muconic Acid Production in Saccharomyces cerevisiae

Acid Experimental Evolution of the Extremely Halophilic Archaeon Halobacterium sp. NRC-1 Selects Mutations Affecting Arginine Transport and Catabolism

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