The effect of different alcohols and other polar organic additives on the cloud point of Triton X-100 in water

Gu, Tingyue; Galera-Gómez, P.A.

doi:10.1016/s0927-7757(98)00710-9

Cited by 155 publications

(79 citation statements)

References 49 publications

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“…We considered two likely mechanisms for this selection: either selection on an individual-cell level based on changes in membrane fluidity as a result of bisabolene accumulation or a more global effect based on the interaction of secreted bisabolene with T20 in the medium. A possible mechanism for the latter option could be via reduction of the cloud point of T20 by interaction with bisabolene released from the cells; a reduction in cloud point temperatures for nonionic surfactants has been demonstrated by the addition of hydrocarbons such as isopentanol and octanol (20). To investigate the cloud point theory, cultures of the pRS strain were set up in SD-gal and SD-gal-T20.…”

Section: Resultsmentioning

confidence: 99%

Use of Nonionic Surfactants for Improvement of Terpene Production in Saccharomyces cerevisiae

Kirby

Nishimoto

Chow

et al. 2014

Appl Environ Microbiol

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dTo facilitate enzyme and pathway engineering, a selection was developed for improved sesquiterpene titers in Saccharomyces cerevisiae. ␣-Bisabolene, a candidate advanced biofuel, was found to protect yeast against the disruptive action of nonionic surfactants such as Tween 20 (T20). An experiment employing competition between two strains of yeast, one of which makes twice as much bisabolene as the other, demonstrated that growth in the presence of T20 provided sufficient selective pressure to enrich the high-titer strain to form 97% of the population. Following this, various methods were used to mutagenize the bisabolene synthase (BIS) coding sequence, coupled with selection by subculturing in the presence of T20. Mutagenesis targeting the BIS active site did not yield an improvement in bisabolene titers, although mutants were found which made a mixture of ␣-bisabolene and ␤-farnesene, another candidate biofuel. Based on evidence that the 3= end of the BIS mRNA may be unstable in yeast, we randomly recoded the last 20 amino acids of the enzyme and, following selection in T20, found a variant which increased specific production of bisabolene by more than 30%. Since T20 could enrich a mixed population, efficiently removing strains that produced little or no bisabolene, we investigated whether it could also be applied to sustain high product titers in a monoculture for an extended period. Cultures grown in the presence of T20 for 14 days produced bisabolene at titers up to 4-fold higher than cultures grown with an overlay of dodecane, used to sequester the terpene product, and 20-fold higher than cultures grown without dodecane.

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Section: Resultsmentioning

confidence: 99%

Use of Nonionic Surfactants for Improvement of Terpene Production in Saccharomyces cerevisiae

Kirby

Nishimoto

Chow

et al. 2014

Appl Environ Microbiol

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“…1 The cloud point (CP) phenomenon is generally observed in nonionic surfactant micellar solutions when the temperature of the surfactant solution is raised to a certain value. [5][6][7][8][9] The increase in turbidity at the CP is generally considered to be due to formation of large aggregates. 10 There is some debate on the relative importance of micellar interaction and micellar growth to the CP.…”

Section: Introductionmentioning

confidence: 99%

A Cloud Point Study on the Micellar Growth of an Amphiphilic Drug in the Presence of Alcohol and Ionic Surfactant

Kim

Shah

2003

J. Phys. Chem. B

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Cloud point (CP) measurements have been performed to investigate the influence of alcohols (C 2 -C 10 OH) on the micellar growth of amphiphilic drug amitriptyline (AMT) in the presence of salt and surfactant. In the case of shorter-chain alcohols (C 4 OH or C 5 OH), the CP increased with increasing alcohol concentration in the presence of a small amount of sodium phosphate because they partition very little in AMT micelles. On the other hand, it steeply decreased with increasing alcohol concentration in the case of longer-chain alcohols (C 8 OH or C 10 OH) due to their considerable partitioning in AMT micelles. The effect of hindering the micellar aggregation was enhanced as the alcohol chain length increased in the case of shorter-chain alcohols. The CP became less sensitive to addition of C 6 OH at higher sodium phosphate concentrations, resulting from incorporation of more C 6 OH molecules into the enlarged micelles. Addition of cationic surfactant cetylpyridinium chloride to the AMT micellar solutions increased the CP because cetylpyridinium cations affect electrostatic interactions with the cationic AMT headgroup, while addition of anionic surfactant, sodium dodecyl sulfate, decreased the CP because of penetration of dodecyl chains into the micelles, resulting in a micellar growth.

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“…The cloud point of a nonionic surfactant depends on the balance between the hydrophilic and hydrophobic interactions and is very sensitive to the presence of additives [12]. Indeed the clouding phenomenon is used to assess the hydrophilic properties of nonionic surfactants [13].…”

Section: Cloud Point Temperaturesmentioning

confidence: 99%

An Energetic Analysis of the Phase Separation in Non-Ionic Surfactant Mixtures: The Role of the Headgroup Structure

Hierrezuelo

Molina-Bolı́var

Ruiz

2014

Entropy

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Abstract:The main goal of this paper was to examine the effect of the hydrophilic surfactant headgroup on the phase behavior of non-ionic surfactant mixtures. Four mixed systems composed of an ethoxylated plus sugar-based surfactants, each having the same hydrophobic tail, were investigated. We found that the hydrophilicity of the surfactant inhibits the tendency of the system to phase separate, which is sensitive to the presence of NaCl. Applying a classical phase separation thermodynamic model, the corresponding energy parameters were evaluated. In all cases, the parameters were found to depend on the type of nonionic surfactant, its concentration in the micellar solution and the presence of NaCl in the medium. The experimental results can be explained by assuming the phase separation process takes place as a result of reduced hydration of the surfactant headgroup caused by a temperature increase. The enthalpy-entropy compensation plot exhibits excellent linearity. We found that all the mixed surfactant systems coincided on the same straight line, the compensation temperature being lower in the presence of NaCl.

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The effect of different alcohols and other polar organic additives on the cloud point of Triton X-100 in water

Cited by 155 publications

References 49 publications

Use of Nonionic Surfactants for Improvement of Terpene Production in Saccharomyces cerevisiae

Use of Nonionic Surfactants for Improvement of Terpene Production in Saccharomyces cerevisiae

A Cloud Point Study on the Micellar Growth of an Amphiphilic Drug in the Presence of Alcohol and Ionic Surfactant

An Energetic Analysis of the Phase Separation in Non-Ionic Surfactant Mixtures: The Role of the Headgroup Structure

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