Hello,
After fermentation, I want to measure residual glucose. I try to use glucose strip but my residual glucose value is very low so the result is wrong (I think).
Is there any another method?
Thanks,
Hi,
If HPLC is not available. May be you can try DNSA method for reducing sugars with photometric detection.
All the best!!
Dear Hacer hacer Iltuzer
you can use HPLC or Dubois 1956 method
good luck
Hi.
HPLC is most recommended. In the absence of this, it can make DNS or glucose oxidase.
Best Regards
Hi,
Most common method used for the remaining glucose measurement is DNS by Miller 1959 (you might have require a little bit variations), HPLC can be also used but you must have RI detector, nor you have to derivatize the sugars. Further there is a YSI glucose analyser which can be also used. This all depend on you that which method suits you best. Since all the three methods works good.
regards
Gaurav
Dear Hacer,
as you obviously aim for quantification of low glucose levels, you need a sensitive method. hplc with RI detection is not very sensitive. you can check enzymatic kits commercially available, which offer photometric or fluorometric measurement for limit of detection. in addition, once we successfully used a GC-based approach, which provided very accurate results and was very sensitive, but needed some effort for sample treatment and derivatization. the protocol is included in one of our old papers. kiefer et al. 2001. JIMB. 28: 338
Best,
Christoph
Hi Haer,
For extremely low extracellular glucose concentration measurement, I would suggest using the GC-MS platform with internal 13C standard for quantification (IDMS). For reference: Wu L, et al, Analytical Biochemistry. 2005; 336(2)
In addition, under this scenario, you must pay attentions to the quenching process which stops any possible catalyze process breaking down by-products ( e.g. trehalose) into glucose. For reference: Mashego, M.R., et al, Biotechnology and Bioengineering, 2003, 83(4)
In our fermentation cases, we determined the residual glucose concentration of continuous cultivation of Penicillium chrysogenum around 6.8 μmol/L.
Hope the above information could be helpful.
Good Luck.
Neil
Hi,
You can use an enzymatic membran (glucose membrane) containing glucose oxidase with YSI biochemistry analyzer, which is quite sensitive with a very small deviation compared to HPLC. Or you can use DNS method for analyzing residual glucose concentration.
Good luck!
Hi guys. I am currently using YSI for sugar detecting and it is really precise between the replicates, but when I try to read the same sample another day (kept in the fridge -20C) it present concentrations really different, sometimes bigger than 35% from the previous day. Does someone have the same problem or some idea what can be the root cause for this?
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