AbstractOne-step fermentation of wheat bran (WB) by Aureobasidium pullulans 2012 to produce ferulic oligosaccharides (FOs) was developed. As the WB concentration was increased, the xylanase activity and yield of FOs increased; the optimum concentration of WB was 50 to 60 g/L, which enhanced xylanase synthesis and the preparation of FOs. A moderate amount of xylan and peptone promoted xylanase synthesis and FO production. The addition of metal ions and surface active agents suppressed the yield of FOs. The optimum medium composition for FO preparation was 10 g/L xylan and 1 g/L peptone added to 60 g/L WB solution. Under these conditions, an FO yield of 774 nmol/L was achieved. According to observations by scanning electron microscopy, the internal structure of WB was obviously disrupted after fermentation. This process featured one-step fermentation of WB without further hydrolyzing, which greatly decreased the raw material cost and thus facilitated its practical application.