Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol

Wang, Zichao; Wu, Jianrong; Zhu, Lan; Zhan, Xi

doi:10.1016/j.biortech.2016.03.096

Cited by 57 publications

(32 citation statements)

References 35 publications

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“…ALE can be utilized to improve production strains by increasing their tolerance to the metabolic product (Hu et al, 2016; Lennen, 2016), by activating latent pathways (Wang et al, 2016) or by enabling the utilization of non-native substrates (Lee and Palsson, 2010). In addition, ALE experiments can improve our understanding of fundamental evolutionary principles that might help us solve rising global challenges of undesirable adaptations like drug resistances in microbial pathogens (Anderson et al, 1950; Govan and Fyfe, 1978; Cohen et al, 1989; Donald and van Helden, 2009; Wensing et al, 2015), cancer (Riganti et al, 2015) or insect resistance toward pesticides (Georghiou, 2012).…”

Section: Introductionmentioning

confidence: 99%

Adaptive Laboratory Evolution of Antibiotic Resistance Using Different Selection Regimes Lead to Similar Phenotypes and Genotypes

et al. 2017

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Antibiotic resistance is a global threat to human health, wherefore it is crucial to study the mechanisms of antibiotic resistance as well as its emergence and dissemination. One way to analyze the acquisition of de novo mutations conferring antibiotic resistance is adaptive laboratory evolution. However, various evolution methods exist that utilize different population sizes, selection strengths, and bottlenecks. While evolution in increasing drug gradients guarantees high-level antibiotic resistance promising to identify the most potent resistance conferring mutations, other selection regimes are simpler to implement and therefore allow higher throughput. The specific regimen of adaptive evolution may have a profound impact on the adapted cell state. Indeed, substantial effects of the selection regime on the resulting geno- and phenotypes have been reported in the literature. In this study we compare the geno- and phenotypes of Escherichia coli after evolution to Amikacin, Piperacillin, and Tetracycline under four different selection regimes. Interestingly, key mutations that confer antibiotic resistance as well as phenotypic changes like collateral sensitivity and cross-resistance emerge independently of the selection regime. Yet, lineages that underwent evolution under mild selection displayed a growth advantage independently of the acquired level of antibiotic resistance compared to lineages adapted under maximal selection in a drug gradient. Our data suggests that even though different selection regimens result in subtle genotypic and phenotypic differences key adaptations appear independently of the selection regime.

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Section: Introductionmentioning

confidence: 99%

Adaptive Laboratory Evolution of Antibiotic Resistance Using Different Selection Regimes Lead to Similar Phenotypes and Genotypes

et al. 2017

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“…Likewise, concentrated cell suspensions in Dulbecco's modified Eagle's medium also exhibit non-Newtonian viscosity behavior (Maisonneuve et al, 2015). The effect of metabolite accumulation on rheology has been studied for plant (Murthy, Lee, & Paek, 2014;Wang, Wu, Zhu, & Zhan, 2016) and bacterial cells (Schelden et al, 2016), in which metabolite accumulation has a significant impact on culture rheology. Mammalian cells also secrete metabolites of varying types throughout the duration of a cell culture (Petersen, McIntire, & Papoutsakis, 1988).…”

mentioning

confidence: 99%

“…Mammalian cells also secrete metabolites of varying types throughout the duration of a cell culture (Petersen, McIntire, & Papoutsakis, 1988). The effect of metabolite accumulation on rheology has been studied for plant (Murthy, Lee, & Paek, 2014;Wang, Wu, Zhu, & Zhan, 2016) and bacterial cells (Schelden et al, 2016), in which metabolite accumulation has a significant impact on culture rheology. The rheology of metabolites in mammalian cell cultures has not been studied; however, findings from plant and bacterial cell cultures indicate that metabolite accumulation could potentially cause changes in the rheology of mammalian cell suspensions as the cells grow.…”

mentioning

confidence: 99%

Non‐Newtonian rheology in suspension cell cultures significantly impacts bioreactor shear stress quantification

Wyma

Martin-Alarcon

Walsh

et al. 2018

Biotech & Bioengineering

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The fields of regenerative medicine and tissue engineering require large-scale manufacturing of stem cells for both therapy and recombinant protein production, which is often achieved by culturing cells in stirred suspension bioreactors. The rheology of cell suspensions cultured in stirred suspension bioreactors is critical to cell growth and protein production, as elevated exposure to shear stress has been linked to changes in growth kinetics and genetic expression for many common cell types. Currently, little is understood on the rheology of cell suspensions cultured in stirred suspension bioreactors. In this study, we present the impact of three common cell culture parameters, serum content, cell presence, and culture age, on the rheology of a model cell line cultured in stirred suspension bioreactors. The results reveal that cultures containing cells, serum, or combinations thereof are highly shear thinning, whereas conditioned and unconditioned culture medium without serum are both Newtonian. Non-Newtonian viscosity was modeled using a Sisko model, which provided insight on structural mechanisms driving the rheological behavior of these cell suspensions. A comparison of shear stress estimated by using Newtonian and Sisko relationships demonstrated that assuming Newtonian viscosity underpredicts both mean and maximum shear stress in stirred suspension bioreactors. Non-Newtonian viscosity models reported maximum shear stresses exceeding those required to induce changes in genetic expression in common cell types, whereas Newtonian models did not. These findings indicate that traditional shear stress quantification of cell or serum suspensions is inadequate and that shear stress quantification methods based on non-Newtonian viscosity must be developed to accurately quantify shear stress.

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“…Meanwhile, the component of the crude glycerol used in this work was the same as used in our previous study. [7] All batch cultures were performed in triplicate.…”

Section: Batch Fermentationmentioning

confidence: 99%

“…[5] From the perspective of long-term development and large-scale production, bioconversion of crude glycerol to value-added chemicals is an effective way of producing many products from crude glycerol, including butanol, biohydrogen, citric acid, dihydroxyacetone, xanthan gum, and polyhydroxyalkanoates. [3,[6][7][8] Gynostemma pentaphyllum, as an edible and medicinal herb, has been widely used in beverages, food, and medicines. [9] In the past decades, many studies have shown that G. pentaphyllum has a variety of biological activities, such as anti-cancer, anti-tumor, anti-gastric ulcer, anti-inflammation, cardioprotection and strengthening the immune system.…”

Section: Introductionmentioning

confidence: 99%

Utilization of glycerol and crude glycerol for polysaccharide production by an endophytic fungus Chaetomium globosum CGMCC 6882

Wang

Tao

Gao

et al. 2019

Preparative Biochemistry and Biotechnology

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Crude glycerol is becoming a financial and environmental liability due to its surplus production from biodiesel industry, and its utilization as a fermentation feedstock for value-added chemicals production has been widely studied. In present work, the capacity of an endophytic fungus, Chaetomium globosum CGMCC 6882, using glycerol and crude glycerol for polysaccharide production was investigated. Results showed that the polysaccharide titers from glucose and glycerol were 1.85 and 3.8 g/L, respectively. Moreover, spore morphology of C. globosum CGMCC 6882 was favorable for polysaccharide production. Meanwhile, impurities in crude glycerol have no effect on polysaccharide production by C. globosum CGMCC 6882. Finally, characteristic results of polysaccharides produced from glucose, glycerol, and crude glycerol have suggested that metabolic flux might be a determinant factor on polysaccharide structure. Taken together, this research provided an innovative approach of utilizing crude glycerol produced from the biodiesel production process.

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Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol

Cited by 57 publications

References 35 publications

Adaptive Laboratory Evolution of Antibiotic Resistance Using Different Selection Regimes Lead to Similar Phenotypes and Genotypes

Adaptive Laboratory Evolution of Antibiotic Resistance Using Different Selection Regimes Lead to Similar Phenotypes and Genotypes

Non‐Newtonian rheology in suspension cell cultures significantly impacts bioreactor shear stress quantification

Utilization of glycerol and crude glycerol for polysaccharide production by an endophytic fungus Chaetomium globosum CGMCC 6882

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