Abstract:

Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) was applied
to analyze molecular weight distribution of hydrolysis products from birchwood xylan and beechwood xylan digested
by Bacillus subtilis xylanase (XynA), obtained through recombinant expression and purified by Ni+-IDA column
chromatography. The hydrolysis products were identified by thin layer chromatography (TLC) and MALDI-TOF/MS.
Results showed the enzymatic hydrolysis of birchwood xylan yielded mainly xylobiose (X2) and xylotriose (X3) as well as
acidic xylooligosacchrides with a degree of polymerization (DP) of 4–12 each including a single methyl-glucuronic acid side
chain. Both xylobiose and xylotriose were found in the hydrolysate of beechwood xylan as well as acidic xylooligosacchrides
with a DP of 4–16 structurally similar to those from birchwood xylan. Therefore, the recombinant XynA has the potential to
produce X2, X3 and acidic xylooligosacchrides.

Key words: xylanase, xylooligosaccrides, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF/MS)