New adsorbent for detoxification of hemicellulose-rich hydrolysate aiming xylitol production

Abstract

Abstract The world demand for sustainable bioprocesses is unquestionable as for researches which aims the biotechnological exploitation of lignocellulosic materials, particularly of its hemicellulosic fractions rich in xylose. Different bioproducts can be obtained from those fractions, although, some bottlenecks still exist such as the presence in the hemicellulosic hydrolysates of toxic compounds for microorganisms which requires previous step of detoxification. Hydrotalcite is used as a new detoxifying agent of the hemicellulosic hydrolysate of sugar cane straw to produce xylitol by Candida tropicalis aiming at a greater removal of phenolics and less loss of sugars. Design of experiments was used for factors effects analysis by a simultaneous way; the influences of pH and temperature were evaluated considering the detoxification process in different times for both uncalcinated and calcinated hydrotalcites adsorbents. While for the calcined hydrotalcite, the temperature was the significant factor, and for the non-calcined there was also an influence of the pH. The hydrotalcite reduced the content of phenolic compounds in the hydrolysate with low loss in sugar content and in xylitol production. Those results suggest new investigations for the proposition of this new adsorbent in search for the development of technologies for obtaining bioproducts in a biorefinery context.