木糖醇发酵液脱色条件的研究

STUDY ON DECOLORIZATION CONDITIONS OF XYLITOL FERMENTATION BROTH

采用颗粒状活性炭对两种木糖醇发酵液进行脱色,就活性炭用量、起始pH值、脱色时间、搅拌速度和温度对脱色效果的影响进行了研究。确定了来自半纤维素水解液的木糖醇发酵液H(FBH)以及来自纯木糖合成培养基的木糖醇发酵液X(FBX)的最佳脱色条件为:在50℃、起始pH值6.0、搅拌速度125r/min的条件下脱色20min,两种发酵液的活性炭用量分别为250和150g/L。如果先将FBH的pH值调节至3.0,抽滤除去因调节pH值而产生的色素沉淀后,回调pH值至6.0,再进行活性炭脱色,则可以节约活性炭用量约50g/L,同时提高木糖醇回收率约6%。该结果将有助于建立一套完整高效的发酵法生产木糖醇的工艺。

Two kinds of xylitol fermentation broths were decolorized using granular activated charcoal. The combinated effects of activated carbon dosage, initial pH value, contacting time, agitation speed, and temperature on the decolorization efficiency of xylitol fermentation broths were investigated. The best decolorization effect was found by adding 250 g activated carbon to 1.0 L fermented broth from hemicellulose hydrolysate (FBH) at 50 ℃ and pH value 6.0, stirring at 125 r/min for 20 min, and 150 g activated carbon to 1.0 L fermented broth from xylose synthetic medium (FBX) at 50 ℃ and pH value 6.0, stirring at 125 r/min for 20 min. When FBH was treated with activated carbon combinated with pH value adjustment and filtration of the precipitated pigment, the activated carbon dosage could be reduced by 50 g/L and the xylitol recovery rate could be increased by 6 %. This work should be helpful to the development of a complete fermentation process for producing xylitol with high efficiency.