This paper reports a pilot-plant production process for xylo-oligosaccharides (mainly xylobiose and xylotriose) from corncob meal by steaming treatment followed by enzymatic hydrolysis and nanofiltration. The effects of corncob meal pretreatment, steaming temperature and time were investigated in order to obtain maximum extraction of xylan and to minimize the autohydrolysis of xylan into xylose. The enzymatic reaction was carried out using Aspergillus niger AN-1.15 endo-xylanase at 55• C and the optimum enzymatic hydrolysis time was 5 h. The conventional downstream processing for purification of xylo-oligosaccharides was incorporated with nanofiltration technology, giving benefits of energy saving and removal of monosaccharides. The final product from 40 kg of corncob meal was 10 dm 3 of xylo-oligosaccharide syrup (800 g dm −3 total sugar), containing 74.5% xylobiose and xylotriose.

H-protein, one of the four component proteins (H, T, P and L) of glycine cleavage system (GCS), is generally considered a shuttle protein interacting with the other three GCS-proteins via a lipoyl swinging arm. We report that without P-, T- and L-proteins, lipoylated H-protein (Hlip) enables GCS reactions in both glycine cleavage and synthesis directions in vitro. This apparent catalytic activity is closely related to the cavity on the H-protein surface where the lipoyl arm is attached. Heating or mutation of selected residues in the cavity destroys or reduces the stand-alone activity of Hlip, which can be restored by adding the other three GCS-proteins. Systematic study of the Hlip-catalyzed overall GCS reactions and the individual reaction steps provides a first step towards understanding the stand-alone function of Hlip. The results in this work provide some inspiration for further understanding the mechanism of the GCS and give some interesting implications on the evolution of the GCS.