Biopolymers

Biopolymers

  • Alireza Bahramian added an answer:
    Is there a relation between "be partially wetted by both water and oil phase" and "be surface active"?

    A polysaccharide aggregate can be partially wetted by both water and oil phase, even if this polysaccharide did not alter the interfacial tension between oil-water? It means is there a relation between these two properties: be partially wetted by both water and oil phase and be surface active?

    Alireza Bahramian · University of Tehran

    By definition, surface active materials have partial tendency to both phases, though they might be more soluble in one of them.  Adsorption of such materials normally reduce the interfacial tension, but it is not a must.  For instance, SDS is a well known anionic surfactant, but its addition to a polymeric solution like PDMDAAC can significantly increase the interfacial tension.  

  • Aleksandar Bubanja added an answer:
    Any advice on the swelling method to investigate cross linking?

    I have some basic questions about the swelling method used to investigate cross linking, any advise is appreciated!

    Q1) Can this method be used for all kinds of polymers, specifically natural polymers such as cellulose?

    Q2) Micro Crystalline Cellulose is completely insoluble in water, but it does swell in water. So is water an appropriate medium to study swelling or should a solvent be used?

    Q3) What could it mean when swelling tests shows a decrease in swelling percentage indicating cross linking, BUT the gel content shows no gel content? Could the decrease in swelling be merely due to increased crystallinity?

    Thank you.

    Aleksandar Bubanja · University of Belgrade

    Dear Fatima,

    A1 to Q1 : cellulose can be used to investigate swelling method . You need to add some cross linker, and then you have made hydrogel. You can use MCC, but consider also CMC (carboxymethyl cellulose), HEC (hydroxyethyl cellulose), etc...

    A2 to Q2 : water is definitely appropriate medium.

    Mr. Abdelkader answered your Q3.

    Best regards.

  • Shilpa Gupte added an answer:
    What are the suitable mediums for thermophilic biopolymer producing anaerobic bacteria?

    I just want to know what are the media are using for themophilic biopolymer producing anaerobic bacteria during the isolation.

    Shilpa Gupte · ARIBAS

    Thermophilic bacteria are sensitive for temperature so kindly maintain the desire optimum temperature requirement of the organisms. For the production of biopolymer provide high concentration of simple carbon source and nitrogen source in the minimum amount, this kind of medium will enhance the production of biopolymer. 

  • Ömer Alkan added an answer:
    Does anyone know a solvent for dissolving of Polylactides and at same time compatible with Polystyrol for cell culture experiments?

    Hey,

    I'm currently preparing an experiment for a Cell Culture practical course in our University and am having some problems.

    The students first synthesize Biopolymers in the first part of the practical course: particularly Polylactides, Polyglycolides in D, L, D/L-forms or copolymerized with NPC or Caprolactone. To solve the solids, we use Chloroform.

    In the second part of the practical course, these Biopolymers are made into thin biofilms and are covered with HaCaT-cells to test the different growth rates on the different Biofilms, but it only works on glass plates, since Chloroform corrodes Polystyrol materials...

    So my question, is there a chemical with both functions: to dissolve the Biopolymers and at the same time is compatible with Polystyrol ? Any experience ? Or should I just use glass ?

    Ömer Alkan · Darmstadt University of Applied Sciences

    Hey,

    thanks for the answers. I talked with my Prof and the problem was that they need these special wellplates for the computer-assisted microscope that takes pictures every hour....so glass is no viable option.

    Thanks, anyways

  • Shakeel Ahmed added an answer:
    How do I incorporate plant extract into a polymer film?

    I have synthesized bio-polymer  film. In order to improve its properties, i want to incorporate the plant extract into the films. Is there any proper method to incorporate extract into films?

    Will the concentration of extract effect the physical properties of films/membranes?

    Keywords: Chitosan, Gelatin, Plant extract, physical properties, thermal properties

    Shakeel Ahmed · Jamia Millia Islamia

    Mariana Patricia Arrieta:  Thank you for your valuable suggestion

  • Ajit Patil added an answer:
    What are the different techniques to measure molecular weight of Biopolymers & Modified Biopolymers?

    Techniques other than GPC, Molecular weight > 100000,

    Ajit Patil · Institute of Chemical Technology, Mumbai

    Thank you all of you for valuable information. I have modified one Biopolymer which is having swelling behavior. After modification it is not soluble in water, DMSO, THF, DCM, Alcohols, Ether, Xylene etc solvents. Even I have tried to low acidic and basic pH it is insoluble in pH range n Buffered solvents too. Thas why it is now very difficult to me to find out technique or method to know exact molecular weight of it. GPC, HPLC techniques were not useful due to solvent problem. 

  • Milad Raiszadeh added an answer:
    How do I design a procedure to extract chitosan from shrimp in a mass scale?

    I mean, we extract it in beaker, but we want a procedure to do it a big scale, I am very grateful if you can help me with some papers, theses or proposals about this topic.

    Milad Raiszadeh · Sharif University of Technology

    Thanks sir , so helpfull

  • Wisnu Tafroji added an answer:
    How do I extract bacterial capsular polysaccharides?

    Hi, i am going to research about bacterial capsular polysaccharide of Streptococcus pneumoniae and i am looking for the best protocol to extract the capsular polysachharide. is there a best method or Kit for extraction and purification of capsular polysaccharide especially from Streptococcus pneumoniae ? thank you very much for your help.

    Wisnu Tafroji · Eijkman Institute

    Hi, Mr. Rao

    Thank you for your recommendations.

    Best regards

    Wisnu

  • Cédric Delattre added an answer:
    How much should we deacetylate chitosan for manufacturing bandage?

    I want some information specially some papers about deacetylation of chitosan for manufacturing bandage

    Cédric Delattre · Université Blaise Pascal - Clermont-Ferrand II

    you're welcome!

    Cédric

  • Sivananth Murugesan added an answer:
    What is the best way of forming soy bean lecithin based micelles?

    From journals , it was clear that soy bean lecithin is good in forming micelles that can be used to deliver hydrophobic drugs when administered as oral drug delivery. what would be the best soy bean lecithin system to form micelle to separate hydrophobic biopolymer from the solution, when I did create soy bean lecithin dissolved in chloroform that can be used to form micelles by cloud point extraction, the added chloroform readily forms a two phase, while those of alcohol and acetone interact with the water, making the system more hydrophilic that the cloud point is already above 80 degree Celsius.

    Can some one suggest me what would be the best concentration and system to study soy bean lecithin micelle by cloud point extraction

    Sivananth Murugesan · National Institute of Technology Karnataka

    Dear Gregory Barshtein , Thanks for the article though it doesnt speak much about the micelle part 

  • Mustafa Çiçekler added an answer:
    Do you know the molecular weight of the cellulose [14C(U)] from Nicotiana tobacum?

    I will work with different organic amendments to be added to soil and cellulose will be one of those. I will also work with 14C and need to know the molecular weight of 14C cellulose from Nicotiana tobacum in order to calculate the exact amount of 14C to be spiked into a 12C cellulose solution from a different source, and, therefore with a different amount of C per gram of soil. On top of that, the manufacturer of the 14C cellulose said that they don't know the molecular weight of their product! Any suggestion?

    Mustafa Çiçekler · Kahramanmaras Sutcu Imam University

    If you know degree of polimerization (DP)  of cellulose, you can calculate molecular weigth. You must know viscosity of cellulose in order to determine DP. For any help, contact me. 

  • Dr Murugesan Muthu added an answer:
    How can I calculate the molecular mass and degree of substitution of biopolymer after modification?

    I have modified the biopolymer, now I want to calculate the molecular mass and degree of substitution of the modified one kindly send me the easy and feasible methods.

    Solubility: product is soluble in water but insoluble in organic solvents 

    Dr Murugesan Muthu · Imperial College London

     please find attached the ref, as you requested. 

    Quantify the amino group before and after functionalisation

  • Cédric Delattre added an answer:
    Does anyone have succinoglycan exopolysaccharide ?

    I think my exopolysaccharide is similar properties like succinoglycan so compare with it I want to buy standard succinoglycan. Can anyone provide me any information regarding this matter?

    Cédric Delattre · Université Blaise Pascal - Clermont-Ferrand II

    Dear Prasad,

    you could send to me 100mg of your EPS in order to investigate FTIR and GC analyses. 

    Regards,

    Cédric

  • Gerhard Behrendt added an answer:
    Can anyone provide me with information about Polyurea resistant paints?

    I want to know about the chemistry of polyurea or polyurethane resistant paint.

    If it is possible please guide me

    Gerhard Behrendt · Technische Hochschule Wildau

    Please, provide information to what resistance you are aiming. There are so many ways to produce polyurethane coatings, e. g. solvent containing, high solids, one component, two component systems, solvenfree systems, aqueous dispersions etc. If you want detailed information you have to define at least the type of application and the type of resistance.

    Polyurea systems are usually two component systems based on isocyanate prepolymers (their design determines properties) and di- or polyamines. By the choice of the composition of the prepolymer and the type of amine you determine the reaction and tack free times and properties. Another way is to you carbamates and perform a trans-amidation with amines in substance or solution. Again, the type of application and desired resistance determine the type of raw material.

    If you want further information on commercial products go to www.nitroil-polyurea.com

  • Edward Michelini added an answer:
    Did anyone experience degradation of disulfide bonds in protein-polymer conjugates upon purification or storage in aqueous medium?

    Stability of disulfide bonds in protein-polymer conjugates?

    Edward Michelini

    Since we live at the bottom of an ocean of O2 reduction of S-S is usually not a problem!  Whats the purification step/buffer where they degrade?

  • Prakrthi A N added an answer:
    How can I electrospin pure starch?

    for prepare starch fiber by electrospining

  • Nick J Walters added an answer:
    Any tips for prolonging gelation time of polysaccharide hydrogel?

    I am currently working with hydrogels formed from gellan gum, a plant-derived polysaccharide which can be gelated using divalent cations such as Ca2+. An alternative method of gelation, which I am investigating, involves the use of polyamines, such as spermine, as the crosslinker. In both cases, the crosslinkers induce gelation instantaneously upon mixing with the GG. This rapid gelation time makes it very difficult to mix the gel homogeneously and also to measure gelation time via rheometry.

    A disaccharide is included in both the GG and crosslinker solutions in order to reduce osmotic pressure. Increasing disaccharide concentration to up to 60 wt% reportedly strengthens the gel; however, the substantial increase in viscosity of the GG solution makes it almost impossible to mix the gel. At 10 wt% disaccharide, the gel can be mixed but it is difficult to make homogeneous and impossible to measure by rheometry.

    I mix the GG with crosslinker at 37ºC. Bringing the temperature down to 4ºC may slow the speed at which the polyamine crosslinks the gel, but conversely, this low temperature makes the GG extremely viscous and difficult to mix.

    I would appreciate any advice that could help me overcome this catch-22 situation!

    Nick J Walters · University of Tampere

    Hi Merlin, thanks very much for the suggestion. This particular project is focused on the use of polyamines for crosslinking the gels, as opposed to divalent cations such as Ca2+. The reason for focusing on this is that certain polyamines have have been shown to have anti-inflammatory effects, protection against oxidative stress and to play a positive role in several regenerative processes. By incorporating them as part of the physical structure of the gel, it is possible to control the physical properties of the gel and to control the release of these and other incorporated molecules.

    I am not looking to incorporate Ca2+, since it would compete with the polyamine, making gelation even more rapid and also potentially preventing some of the polyamine from binding and causing it to be released more rapidly.

    GDL appears to act as a chelating agent. Do you or your colleague think it is possible that this would act on the polyamine in a similar way to how it acts on the CaCO3, delaying gelation via the polyamine crosslinker?

  • Muhammad Radifar added an answer:
    What is different between chitosan and alginate?

    Can anyone tell me why lysozyme could enzymatically degrade chitosan while alginate is stable under same conditions?

    Muhammad Radifar · Gadjah Mada University

    Yes, that's true, but unless lysozyme is a non-specific enzyme like lipase or CYP450, then in my opinion lysozyme won't be able hydrolyze other substrate than chitosan/chitin. Carboxyl versus amine aside, there are 5 chiral atom in every monomer, which means every hydroxide/ether group must be in the correct position to be bound by the corresponding amino acid residue inside the binding cavity of lysozyme.

  • Dorra Ghorbel added an answer:
    How can I choose the column and the standards for an HPSEC apparatus?

    We must measure the molecular mass distribution of biopolymers: polysaccharides (amylose, fibers.) and proteins.

    Dorra Ghorbel · University of Carthage

    Thank you very much, I'll read them.

  • Milad Raiszadeh added an answer:
    How can we get Chitosan from shrimp shell?

    I want some information specially some papers about chitosan biopolymer and the industerial methods to get it from shrimp shell

    Milad Raiszadeh · Sharif University of Technology

    thanks sir , i get useful hints from it

  • Bernardino Isaac Cerda-Cristerna added an answer:
    Can anyone suggest me an adoptable procedure(s) to synthesize PLA nanoparticles of size around 75-100nm?

    I had gone through certain procedures. Some used rare stabilizers like plant extracts (which are not easily accessible), copolymers or the synthetic procedures are vague like they did not mentioned how they synthesized PLA precursor.

    Bernardino Isaac Cerda-Cristerna · Universidad Autónoma de San Luis Potosí

    You can use a spray-dryer machine. It creates a spray (nano-drops) that forms solid nano-particles when the solvent into the nano-drops is removed by high temperature.  You can change formulation parameters (mass of polymer, volume of solvent, pressure in the pump of the system, etc) to get different sizes of the NP. In addition, the technique is very useful when you want to encapsulate hydrophilic molecules. 

  • Ann Burman added an answer:
    Does anyone have the datasheet of Novozym 476 / Fiber Care R?

    I am currently working on enzyme-treated pulps and I would like to know the optimum working conditions for these type of cellulases.

    The fact is that I cannot find the datasheet of this commercial product and Novozymes does not provide me any information a part from its activity factor, viscosity, density...

    It would be really helpful if someone could tell me where can I download it..

    Thank you in advance

    Ann Burman · Novozymes

    Hej Marc, please email me at Annb@novozymes.com. I will be able to help you.

    Best regards, Ann

  • Nadezhda Traycheva Petkova added an answer:
    Can someone please advise me about the DDSA (dodecenylsuccinic anhydride) derivatisation of Inulin and Gum Arabic?

    Is there any possibility of double esterification with both carboxyl groups on the DDSA bonding to  neighbouring OH groups on the inulin (or the gum) and if so, under what conditions can this occur? Has anyone got any similar information concerning the esterification of starch and other polysaccharides?

    Nadezhda Traycheva Petkova · University Of Food Technology - Plovdiv

    https://www.researchgate.net/publication/260830412_P2.3_-_New_fatty_acid_esters_of_soluble_dietary_fibers_..._ARTICLE

  • Jeshwanth Rameshwaram added an answer:
    How do I determine the gel point using rheology?

    So I've been perusing Winter and Chambon's paper from '86 and what I've garnered is that you asses multiple solutions near the critical point by sweeping frequency an measuring G' and G''. They seem to mention they have an experimental range of five orders of magnitude which to me seems like it would go beyond the linear viscoelastic region. Looking for experimental suggestions: all welcome, thanks!

    Jeshwanth Rameshwaram · ATS RheoSystems

    Maybe I am missing something here, but the gel point can be determined relatively easily using an oscillation temperature sweep; if you are looking for effect of temperature on when the gel point occurs, or use an oscillation time sweep at constant temperature. The frequency used in these measurements can be determined by trial and error, but 1 Hz usually works. The measurements would need to be in the strain controlled mode. The strain needs to be small enough to not perturb the inherent structure of the system. One way to pick the strain is to use as small of a strain amplitude as possible that would give reliable data (enough torque to generate a good signal to noise ratio). As the gelation progresses the signal gets stronger. The abrupt drop in phase angle (stress/strain) and increase in G' are good indicators of gelation.

  • M Catarina M D Almeida added an answer:
    How can I check cytotoxicity of Biopolymer (PHA)?

    After extracting Polyhydroxyalkanoates I want go for toxicity checking with the cell lines, but I am a bit confused in which solvent I will dissolve it so that I can apply it to cell lines?

    M Catarina M D Almeida · Cooperativa de Ensino Superior Egas Moniz

    Hello.

    Check our paper, maybe it will help you: Polyhydroxyalkanoates: Waste glycerol upgrade into electrospun fibrous scaffolds for stem cells culture. http://www.sciencedirect.com/science/article/pii/S014181301400292X

  • Ramkumar Ponnuraj added an answer:
    How to control the degree of polymerization in chitosan oligomers production?
    -
    Ramkumar Ponnuraj · Apex Laboratories

    Enclosed an article which may help your research 

About Biopolymers

Polymers synthesized by living organisms. They play a role in the formation of macromolecular structures and are synthesized via the covalent linkage of biological molecules, especially AMINO ACIDS; NUCLEOTIDES; and CARBOHYDRATES.

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