A spectrophotometric method for quantitative determination of xylose in fermentation medium
ABSTRACT Monitoring the consumption of sugars during fermentation is a key to optimizing product formation and maintaining a healthy environment for microorganisms. Diffi-culty arises in the availability of a rapid, inexpensive and sensitive method for the detection of sugars because fermentation media are a complex mix of nutrients, cell debris, waste and target products. A method involving reaction-based UVeVis spectro-photometry for the quantitative determination of xylose as the target sugar was devel-oped. Factors affecting xylose concentration measurements such as hydrochloric acid concentration, heating time and the amount of Fe 3þ catalyst were investigated. A continuous scan revealed the working wavelength to be 671 nm. The effect of other components in the fermentation broth was found to be negligible. Absorbance shows a linear relationship with xylose concentration within a range of 0.1e0.5 g/L. Xylose concentrations from fermentation samples obtained at specific time intervals (0e168 h) were determined with the method and compared with YSI 2700, an enzyme electrode, HPLC-ELSD method, currently a common technique for measuring xylose and GC aldo-nonitrile sugar derivatization method. Dilution is necessary for comparable xylose concentrations with YSI 2700 and HPLC-ELSD. Xylose concentration measurements obtained with the UVeVis spectrophotometric method although quantitatively compa-rable to HPLC-ELSD xylose measurements were easily and conveniently obtained compared to YSI 2700, HPLC-ELSD and GC derivatization methods.
- [Show abstract] [Hide abstract]
ABSTRACT: This study demonstrated a new method for analyzing five-carbon sugars in biomass hydrolysate by headspace gas chromatography (HS-GC). The proposed method is based on the reaction of five-carbon sugars with sulfuric acid, in which five-carbon sugars are converted to furfural that is measured with full evaporation headspace gas chromatography (FE-HSGC) using a flame ionization detector (FID). The experimental results showed that the complete conversion of five-carbon sugars to furfural can be achieved at 70 °C within 5 min, with a H2SO4 concentration of 15 mol/L. Moreover, it can be seen that the measurement precision (RSD ≤ 0.72%) and accuracy (recovery = 99.3 ± 1.9%) are very good. The operating procedure is simple, and the testing time is short. In addition, the proposed method does not need organic reagents. All of these demonstrate that the peoposed method is a rapid, reliable, and environmentally friendly method that is quite suitable for the analysis of five-carbon sugars in the hydrolysate during the process of lignocellulosic biomass conversion.Energy & Fuels 07/2014; 28(7):4247-4250. DOI:10.1021/ef500037s · 2.73 Impact Factor