Effects of thermal, alkaline and ultrasonic treatments on scleroglucan stability and flow behavior

Viñarta, Silvana Carolina; Delgado, Osvaldo Daniel; Figueroa, Lucía I. C. de; Fariña, Julia Inés

doi:10.1016/j.carbpol.2013.01.063

Cited by 36 publications

(19 citation statements)

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“…In this context, it is important to investigate the stability of the triplex in comparison to the single strand conformation (ss-Sclg). It is known that the Sclg triplex is stable in water solution up to 135 ∘ C. Furthermore, triplex stability decreases by adding DMSO to the water solution, or by increasing the alkalinity, with a triplex unfolding observed close to pH 13 [6][7][8]. Very similar behaviours have been reported for other (1 → 3)--Dglucans with 1,6-linked branches, from a structural point of view, closely related with Sclg [9][10][11][12].…”

Section: Introductionsupporting

confidence: 67%

Relative Stability of the Scleroglucan Triple-Helix and Single Strand: an Insight from Computational and Experimental Techniques

Bocchinfuso

Meisina

Conflitti

et al. 2016

Zeitschrift Für Physikalische Chemie

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Scleroglucan (Sclg) is a polysaccharide that exhibits a triple helix conformation (triplex), both in aqueous solution and in the solid state, which is lost in DMSO solution, at high temperature and at high pH values. The triplex conformation is characterized by a high rigidity, responsible of Sclg peculiar properties. Although the relative stability of triplex and single strand has already been investigated, different structural details are still missing. In the present study, we analyse the structural properties and the factors stabilizing the single chain and the triple helix of Sclg in different conditions. To this end, we simulated both systems in water and in DMSO. The triple helix has been also simulated in the presence of chemical damages on one of the three strands (to reproduce in silico the effect of sonication) or by inducing a partial unfolding of the triplex structure. The computational results have been compared with experimental evidences in which the triplex denaturation, at alkaline pH values, has been followed by monitoring the UV and CD spectra of Congo red, used as a probe molecule. Our results indicate that sonication breaks the Sclg chains without appreciably changing the stability of the other tracts of triple helix. The simulated perturbed or partially unfolded triplexes show a clear tendency to form less Unauthenticated Download Date | 6/23/16 1:58 PM 2 | G. Bocchinfuso et al. ordered aggregates. Finally, our simulations put in evidence an important role of the hydrophobic interactions both in the triplex stability and in the aggregation processes observed after induced denaturation.

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Section: Introductionsupporting

confidence: 67%

Relative Stability of the Scleroglucan Triple-Helix and Single Strand: an Insight from Computational and Experimental Techniques

Bocchinfuso

Meisina

Conflitti

et al. 2016

Zeitschrift Für Physikalische Chemie

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“…Meanwhile, interstrand hydrogen bonding at the center of the triplex stabilizes the macromolecular structure (Atkins and Parker, 1968; Bluhm et al, 1982; Sletmoen et al, 2009). However, at higher NaOH concentrations, where drastic changes in viscosity are commonly observed, the triple-strand helices probably undergo the ionization of hydroxyl groups which thus disrupts hydrogen bonds and prompts the subsequent polysaccharide denaturation (Fariña et al, 2001; Viñarta et al, 2013a). …”

Section: Scleroglucan Chemical Structure and Conformational Featuresmentioning

confidence: 99%

“…Additionally, the EPS neutral nature allows keeping pseudoplasticity even in the presence of a variety of salts, such as NaCl, KCl, CaCl 2 , MgCl 2 , and MnCl 2 (Fariña et al, 2001; Viñarta et al, 2013a). In contrast, slightly refined solutions (2 g/L) of commercial scleroglucans and crude polymer isolates from fermentation broths produce lower viscosity solutions with a lesser ability to retain stable rheological features when exposed to alkali, high temperatures, or salts (Wang and McNeil, 1996; Viñarta et al, 2007, 2013a). Differences depending on the EPS purity grade were also found between Biopolymer CS6 (60–70% scleroglucan) and Biopolymer CS11 (85–90%; Survase et al, 2007a).…”

Section: A Brief Pane On Scleroglucan Properties and Applicationsmentioning

confidence: 99%

“…On the other hand, mimicking the behavior of other closely related β-(1-3)- D -glucans, scleroglucan triple helices can also be affected by denaturing conditions (e.g., pH ≥ 13), where destabilization of the interstrand H-bonding leads to the dissociation into single stranded random coils (Deslandes et al, 1980; Norisuye et al, 1980; Bluhm et al, 1982; Yanaki and Norisuye, 1983; Ensley et al, 1994). Denaturation of triplexes may occur in alkaline solutions (≥0.25 M NaOH), in dimethylsulfoxide (DMSO; water weight fraction, WH < 0.13), or by increasing the temperature above the triplex melting temperature (T m ≅ 135°C; Fariña et al, 2001; Sletmoen et al, 2009; Viñarta et al, 2013a). Typically, denatured solutions show much lower or nil viscosity as compared to the triplex-containing solutions.…”

Section: A Brief Pane On Scleroglucan Properties and Applicationsmentioning

confidence: 99%

“… Flowchart illustrating the main stages during production and downstream processing of scleroglucan from S. rolfsii ATCC 201126 (Fariña et al, 1998; Viñarta et al, 2013a). Chain starts with production at fermenter scale with MOPT culture medium under the following operative conditions: 400 rpm, 0.5 vvm and 30°C, in a BioFlo 110 fermenter (New Brunswick Sci.)…”

Section: Reviewing the Knowledge And Advances On Scleroglucan Productionmentioning

confidence: 99%

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Microbial production of scleroglucan and downstream processing

2015

Self Cite

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Synthetic petroleum-based polymers and natural plant polymers have the disadvantage of restricted sources, in addition to the non-biodegradability of the former ones. In contrast, eco-sustainable microbial polysaccharides, of low-cost and standardized production, represent an alternative to address this situation. With a strong global market, they attracted worldwide attention because of their novel and unique physico-chemical properties as well as varied industrial applications, and many of them are promptly becoming economically competitive. Scleroglucan, a β-1,3-β-1,6-glucan secreted by Sclerotium fungi, exhibits high potential for commercialization and may show different branching frequency, side-chain length, and/or molecular weight depending on the producing strain or culture conditions. Water-solubility, viscosifying ability and wide stability over temperature, pH and salinity make scleroglucan useful for different biotechnological (enhanced oil recovery, food additives, drug delivery, cosmetic and pharmaceutical products, biocompatible materials, etc.), and biomedical (immunoceutical, antitumor, etc.) applications. It can be copiously produced at bioreactor scale under standardized conditions, where a high exopolysaccharide concentration normally governs the process optimization. Operative and nutritional conditions, as well as the incidence of scleroglucan downstream processing will be discussed in this chapter. The relevance of using standardized inocula from selected strains and experiences concerning the intricate scleroglucan scaling-up will be also herein outlined.

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Pharmaceutical Natural Polymers: Structure and Chemistry

Mogoşanu

Grumezescu

2015

Handbook of Polymers for Pharmaceutical Technologies

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Effects of thermal, alkaline and ultrasonic treatments on scleroglucan stability and flow behavior

Cited by 36 publications

References 40 publications

Relative Stability of the Scleroglucan Triple-Helix and Single Strand: an Insight from Computational and Experimental Techniques

Relative Stability of the Scleroglucan Triple-Helix and Single Strand: an Insight from Computational and Experimental Techniques

Microbial production of scleroglucan and downstream processing

Pharmaceutical Natural Polymers: Structure and Chemistry

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