Purification and characterization of a xylanase from Aspergillus carneus M34 and its potential use in photoprotectant preparation

An extracellular xylanase was purified to homogeneity from a culture of Aspergillus carneus M34. In contrast to xylanases from other microorganisms, only a low-molecular weight xylanase, approximately 18.8 kDa with a pI value of 7.7–7.9, was purified in this investigation. The optimum temperature and pH of this purified xylanase activity were 50 °C and 6, respectively. The xylanase was more stable under alkaline conditions and retained more than 50% activity after 12 h incubation at pH 7–9. Considering of its characteristics and N-terminal sequence, this xylanase was concluded as a new one belonging to the group I of family 11 endoxylanases. In addition, hemicellulose of coba husk was selected as the substrate for xylooligosaccharide preparation owing to its higher specificity for this xylanase. Feruloyl xylooligosaccharides were separated and shown potential antioxidative capacity in a cell model of ultraviolet B (UVB)-induced oxidative damage to keratinocyte xb-2.