Study On Bioconversion Of Xylose Mother Liquor In The Production Of Xylitol And L-arabinose

Xylose mother liquor is the product of crystalline D-xylose, massecuite by centrifugal separation to obtain liquid. In the mother liquor solids content is about 60%, its main composition is D-xylose, L-Arabinose, D-glucose, D-galactose. In the content of xylose mother liquid solid D-xylose,L-arabinose,D-glucose, D-glactose, in respectively 12%,44%,11%,28%.Before 2008, the xylose mother liquor was used mainly for domestic production of caramel pigment, relatively low value-added. With the development of industry chromatography technology, some functional sugar companies start to extract the D-xylose and L-arabinose component, realizes the high added value utilization of xylose mother liquor. Xylose mother liquor price from the original 300-700 yuan/ton, it rose to 1200 yuan/ton. In 2008 May, L-Arabinose because it can inhibit the absorption of sucrose and many other special health benefits, approved by the then Ministry of health for the new resources of food.In the xylose mother liquor of high added value utilization, mainly in two ways: 1, used by Saccharomyces cerevisiae in mother liquor of D-glucose will be removed, and then use the industrial chromatographic separation purity of about 78% D-xylose and the purity of about 80% L-Arabia sugar two components respectively, and then get D-xylose and crystallization L-Arabinose two products; 2, by Candida yeast will consume in mother liquor of D-glucose, and then transformed D-xylose to xylitol, reuse of industrial chromatographic separation, and then were obtained and L-arabinose crystallization of xylitol. It is obviously that the first process is better than another one. This is because found in HPLC detection, the retention time of D-xylose and L-Arabinose is very close, so it is difficult to be separated, the yield is low. However, the xylitol and L-Arabinose HPLC retention time is about 7 minutes, the peak distance is large and suitable for separation.This paper is in accordance with the idea of the second process, research of whole process from strains to obtain final xylitol and L-arabinose.This paper studied the important factors of the fermentation conversion, the best level of substrate concentration 12g/L, yeast extract dosage 8.5g/L, aeration rate 1.0vvm. The order of the factors to fermentation was:the concentration of substrate> aeration> yeast extract dosage. Xylose mother liquor, corncob steam explosion deacidification solution can produce xylitol and L-arabinose by fermentation. In the test, the corncob steam explosion deacidification solution as substrate, the conversion rate of xylitol was 84% and L-arabinose retention rate was 82%; using xylose mother liquor as substrate and xylitol conversion rate was 87%, L-arabinose retention rate was 79%. The PCR642, UBK555 and CR1320 three resins were separately evaluated, and the separation factor of PCR642 was 2 and the most efficient.. With corn cob steam explosion deacidification solution as substrate, xylitol conversion rate was 81%, L-arabinose retention rate was 80%,3 times for a total of feeding 900 kg corncob, the production of xylitol was 108.2kg, L-arabinose was 30.5kg. This paper provide a reference in search of xylose mother liquor and other enriched in xylose, arabinose liquid, to produce xylitol and L-arabinose in efficiency, environmental protection, low cost and easy to realize production process.