Hi Tanya;

I see that your question is not yet answered. I do not work in this area of research, but would think that the chemical analysis methods used in analyzing wood and other lignocelluloses should work in the case of seaweed samples. You need to do a literature search and see what other researchers in your field are using or what their experiences have been with one or the other of the methods used..

Umesh, thank you very much for your suggestion!

Hello,

You could try running ADF (acid detergent fibre) and ADL (acid detergent lignin) assays. ADF will give cellulose plus lignin and ADL will give lignin, so you could work out the cellulose content that way. Forage analysis labs should be able to do this for you if you don't have the equipment.

This paper mentions values for a few seaweeds: http://septentrio.uit.no/index.php/rangifer/article/viewFile/1152/1095

You should be able to do monosaccharide analysis after acid hydrolysis. Typical approach would be to hydrolyse your sample in strong conditions (typically using sulphuric acid) and weak conditions ( typically using TFA). After hydrolysis measure the released monosaccharides using your favourite technique ( GC of alditol acetates, GC of TMS derivatives, or HPAEC-PAD). The TFA hydrolysis does not hydrolyse cellulose, so any Glucose measured in this analysis can be subtracted from that measured using the sulphuric acid hydrolysis and then you have an estimate of cellulose.. At least, that approach works for terrestrial plants.

Good luck

Thank you, Susan! I am afraid we have to do it in our lab, but your suggestion make me think, that we could find a forage lab and ask them. May be they will be so kind.

...and give some method details.

this one cal help

Scopus

EXPORT DATE:12 Oct 2013

Siddhanta, A.K., Kumar, S., Mehta, G.K., Chhatbar, M.U., Oza, M.D., Sanandiya, N.D., Chejara, D.R., Godiya, C.B., Kondaveeti, S.

Cellulose contents of some abundant indian seaweed species

(2013) Natural Product Communications, 8 (4), pp. 497-500.

http://www.scopus.com/inward/record.url?eid=2-s2.0-84876219483&partnerID=40&md5=8f367d4fd26b745f84c4cadfefb6f5e6

DOCUMENT TYPE: Article

SOURCE: Scopus

You could consider following applications:

http://www.ankom.com/media/documents/Method_7_Crude_Fiber_Analysis_04-14-11_A200,A200I.pdf

http://www.ankom.com/media/documents/Method_5_ADF_4-13-11_A200,A200I.pdf

http://www.ankom.com/media/documents/Method_6_NDF_4013011_A200,A200I.pdf

These applications are intended for feed analysis but it is possible to determine fibre in other matrixes.

This is web page for more information: http://www.ankom.com/product/ankom-200-fiber-analyzer,-120v,-domestic.aspx

We use it in our laboratory for over 5 years for various types of samples and had no problems.

You can also try pyrolysis - gas chromatography/mass spectrometry technique.(PY-GC/MS)

Giorgio, Sasa and Nino, looked through suggested by you links and references. Very much appreciated your time and efforts. I have more clear idea what I am going to do now.

I am going to tally the UV-Vis technique first. We have all reagents and instruments for glucose assay (Sigma). It should be easy, reliable, not expensive approach. If the method will not work I move to another colorimetric method and then to HPLC or GC-MS one.

Once again, I would like to say thank you to everybody. I am going to wright about the results of my experiments later.

For the Van Soest method (ADF and ADL assays), it must be kept in mind that has been developed for forages biomasses. When it used on samples with high contents of uronic polysaccharides, a neutral detergent extraction must be done just before the acid detergent extraction (to extract the uronic polysaccharides). Otherwise, the ADF fraction will be highly contaminated by uronic polysaccharides (they precipitated in the acid detergent) and the washing of the ADF fraction will be time consuming (slow and difficult filtration). Therefore, the ADF fraction and the cellulose content (ADF-ADL) will be highly overestimated.

For the UV-Vis techniques estimating a specific polysaccharide, there is often an interference of the other polysaccharides.

The best way to estimate the cellulose content is by using the monosaccharide analysis after acid hydrolysis (by taking into account the degradation of the monosaccharides during the hydrolysis).

Thank you Bruno! I cheese the digestion with 72% sulphuric acid (boiling for 4.5 hrs). Then neutralization of digest with sodium hydroxide solution (stack a bit on this part, really the pH adjustment is my least favorite) to pH between 6.0-7.2. After that I am going to perform enzyme assay using glucose as a standard.

One simple method is the following:

Updegraff, David M., 1969, Semimicro determination of cellulose in biological samples, Anal. Biochem. 32:420-424.

The only problem is trying to determine what to use as a reference standard. My coauthor and I will be discussing this in a paper to be submitted very soon.

Thank you Allen!