Preparation and Properties of Agar Sulfates

Fuse, T.; Suzuki, Takamasa

doi:10.1080/00021369.1975.10861571

Cited by 6 publications

(15 citation statements)

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“…It is well-known that the content of sulfate groups, in addition to MW, shows a good correlation with gel strength of agars and agar sulfates (Fuse and Suzuki, 1975). From the above data, it is thought that the content of sulfate groups and the MW influence somewhat the T g for the agar and its component polymers.…”

Section: Choice Of Eluent For Sec-lallsmentioning

confidence: 86%

“…They are divided into agarose and agaropectin by the degree of substitution (Hjertén, 1962;Fuse and Suzuki, 1975). It is well-known that the degree of substitution and the molar ratio of D-galactose to 3,6-anhydro-L-galactose relate to gelling ability, which is the most important property of the agar (Fuse and Suzuki, 1975;Bourret et al, 1986).…”

Section: Introductionmentioning

confidence: 98%

“…The agars consist of polysaccharides that differ in the level of substitution by sulfate, pyruvate, and methoxyl groups (Duckworth and Yaphe, 1971;Lahaye et al, 1986). They are divided into agarose and agaropectin by the degree of substitution (Hjerte ´n, 1962;Fuse and Suzuki, 1975). It is well-known that the degree of substitution and the molar ratio of D-galactose to 3,6anhydro-L-galactose relate to gelling ability, which is the most important property of the agar (Fuse and Suzuki, 1975;Bourret et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

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Determination of Molecular Weight of Agars and Effect of the Molecular Weight on the Glass Transition

Mitsuiki

Mizuno

Motoki

1999

J. Agric. Food Chem.

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A novel procedure to determine the molecular weight (MW) and MW distributions for various agars is described. The MW values of commercial agars, an agarose, an agaropectin, and hydrolyzed agaroses were determined by size exclusion chromatography-low angle laser light scattering, using 4.0 M guanidine hydrochloride as eluent to avoid gelation. The MW for the commercial agars was between 106 400 and 243 500 with polydispersity between 1.283 and 6. 600. The MW of the agarose separated from a commercial agar was lower than that of the agaropectin. To prepare agaroses with different MW values, the obtained agarose was hydrolyzed. The MW of the agarose decreased with hydrolysis time, and the polydispersity, on the contrary, increased. The glass transition temperature (T(g)) of agarose with different MW values and that of agaropectin were measured by differential scanning calorimetry. The T(g) of the agarose was higher than that of the agaropectin with higher MW. The T(g) of agarose increased with MW.

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Section: Choice Of Eluent For Sec-lallsmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Determination of Molecular Weight of Agars and Effect of the Molecular Weight on the Glass Transition

Mitsuiki

Mizuno

Motoki

1999

J. Agric. Food Chem.

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“…Based on this index and limit, we established a new criterion for the suitable AP strength for isolation culture under strong acidic conditions. Fuse and Suzuki (1975) investigated the effect of molecular weight, monomer composition and abundance ratio of sulfo groups on the gelling ability of agar and reported that molecular weight had the strongest effect. Under strong acidic conditions, agar gel hydrolysis is exacerbated, reducing the average molecular weight and thus the AP breaking stress.…”

Section: Discussionmentioning

confidence: 99%

Determination of available breaking stress of agar and gellan gum plate culture methods and the duration of bacterial culture under strong acidic conditions

Takano

Aoyagi

2020

J. Appl. Microbiol.

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Aims: Several acidophilic bacteria have not been cultured, primarily owing to the lack of suitable culture methods under strong acidic conditions. This study aimed to quantitatively evaluate the strengths of the agar plates (AP) and gellan gum plates (GP), and optimal culture periods under strong acidic conditions. Methods and Results: To define the lower limit of plate strength for bacterial isolation culture, the diameter of Escherichia coli K12 colonies and the breaking stress of plates at different concentrations of gelling agents, medium composition and pH conditions were determined. The lower limit of available strength of AP and GP was 19Á6 and 14Á8 kPa, respectively. Medium composition slightly affected AP breaking stress, although GP with a high cationic concentration medium could not be prepared. Conclusions: Assessment of the strength limits of AP and GP revealed that AP is not suitable for prolonged bacterial culture (≥72 h). Furthermore, GP was completely ineffective for bacterial culture under highly acidic conditions (≤pH 1Á0). Significance and Impact of the Study: Our quantitative evaluation method based on breaking stress is a potentially valuable tool to understand the state and the suitable limit of plate culture methods in more detail under various conditions.

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“…These characteristics, along with the pattern and degree of substitution, the molecular weight and chemical composition determine the physical properties and consequently the quality of agar. Besides, like most natural compounds, agar properties may also be influenced by the species and culture environment (Fuse and Suzuki 1975;Lee et al 2017;Vergara-Rodarte et al 2010;Armisen and Galatas 1987). Although the general aspects of the extraction process are known, this is a time-consuming process that results in considerable amounts of waste.…”

Section: Agarmentioning

confidence: 99%