What do you want it for? You can get soluble xylan (beechwood) from Sigma.

http://www.sigmaaldrich.com/catalog/product/sigma/x4252?lang=en®ion=US

I am working with the beechwood xylan from Sigma, but can't get it dissolved in water at 10% or higher. I need to do enzyme hydrolysis on the intact but dissolved xylan.

We use Sigma Beech wood xylan as substrate(1%) for xylanase assay, in which we first take few ml (say for 5-10 ml) absolute alcohol (95% ethyl alcohol) along with water and place it on hot plate magnetic stirrer. Once the slurry is prepared then it is subjected to heating till 100 deg c with contiunuous stirring on hot plate magnetic stirrer. The substrate xylan is completely dissolved. Then the solution is kept for cooling at room temp and the after volume is completed by adding D water.

Hope this will solve your problem.

The solution may be very slightly opalescent due to the presence of trace amounts of protein.

Thanks Ranveer, I'll try adding some alcohol in the beginning and stirring while it is dissolving to get a higher concentration in the end. We could get to 4% xylan by just heating to 100 degrees, but above that I'll have to get more inventive. By increasing the pH to 9 there seems to be some improvement in solubility, but the solution also darkens which might indicate some breakdown in the xylan structure which is not desirable for our application.

Add some DMSO before you add a lot of water. . DMSO is good solvent and it is compatible to proteins. I did that before but not with 10%. It make xylan solution very clear.

Thanks Daniel, I'll try that as well. I'd like to get the solutions clearer.

Dear Manda

Any updates regarding solubility of Xylan. Did my suggestion worked?

Dear Ranveer

Sorry, I haven't had a chance to do the solubility test with the added ethanol yet. Our lab is very busy. This morning I plan on doing it. Will give some feedback. We could go to 5% by heating to 110 degrees for 30 minutes with only water.

Dear Ranveer

I'm sorry to report that the ethanol did not succeed in increasing the solubility of a 10% xylan solution. It is a very opaque slurry which also darkened considerably. Most probably it is because we are working at a too high xylan concentration. So far slight increases in temperature, for instance from 100 to 110 degrees celcius have made a visible impact on solubility at 5%. I will continue trying to increase the concentration slowly and adjusting the temperature as needed. The DMSO as suggested by Daniel should work well. I'll give that a try.

I would like to give some more feedback. DMSO on its own did not succeed in dissolving Beechwood Xylan from Sigma at a concentration of 4.4% even with heating to 80 degrees celcius. So, dissolution in 100 or 110 degrees celcius water for short periods 15 minutes still gets the best results. The highest we could go so far is 5%. o

Im sorry, did you autoclave your xylan or filter sterilize it? wont it destroy the xylan structure if we autoclave it

Hi Sarah, sorry for taking so long in answering because I haven't been able to look around on ResearchGate much due to several circumstances. No, we didn't need to autoclave or filter sterilize the xylan. I would be careful to keep it at very high temperature for long periods of time though. It's hard to say whether you might get some decomposition then. You could test it on HPLC. If you see a lot of breakdown products after autoclaving it would be an indication that you are losing a lot of the original structure of the polymer. I'm thinking you might be able to test several types of filters. PVDF syringe filters are usually a good choice, but you could also give the hydrophilic PTFE kind a try. You could determine the weight of a xylan solution before filtration and then again after filtration. Then also have a control with the same composition as your xylan solvent and put it through the same test. Some of the solvent will remain in the filter and you need to compensate for that mass. If you see a large decrease in mass after filtration it is an indication that most of the xylan is stuck in the filter, but I suspect then the filter will block up very soon as well. If the syringe filter test works well you could also filter larger volumes using membrane filtration.

Did you prove it yet? I still got the same problem. After i precipitated the xylan, i try to dissolution for enzyme assay but it is hard to disslove them. Please share your method. Thanks you

what is the other way precipitating beechwwod /birchwood xylan apart from organic solvents

To dissolve xylan: Try heating to 40-65 deg with ultrasound. It helped me at least with 5% xylan solution

Guys, did anyone tried strerilization of xylan in autoclave? What was the effect?

I also use xylan beechwood for my xylanase assay. 

I wanted to ask on the method of xylan solution storage.

Is it ok for me to store the readily prepared 1% xylan solution in 4 degree celsius for 3-4 weeks? or I have to prepare new xylan solution in every xylanase assay im working on?

Hi Nizzal

I would be a bit concerned about bacterial contamination forming in your 1% xylan solution if you keep it at 4 degrees for 3-4 weeks. Perhaps you could try freezing in small batches. You might get some degradation in xylan structure on freeze-thaw, but at least if you freeze in small batches each batch will only go through one freeze-thaw cycle. I haven't tried that before but it might work.

Hi

I think when we want to prepare solution containing lower than 1% of xylan, we should just solute it under high temperature (80 oC). In other cases i think that the DMSO is the best choice.

In water with heating between 50°C and 70°C or using ultrasound system

@ Abdellatif Barakat : If I heat Xylan up to 70 Degree C with ultrasound, will it break the xylan structure? I dont want to do that...

Please advice...thanks