Production and partial characterization of cellulase free xylanase by Bacillus subtilis C 01 using agriresidues and its application in biobleaching of nonwoody plant pulps

Aims: To optimize the solid-state cultivation conditions for xylanase production using agriresidues and testing the biobleaching efficiency of xylanase on nonwoody plant fibre materials. Methods and Results: An extracellular cellulase free xylanase was produced from Bacillus subtilis C 01 using various inexpensive substrates under solid-state cultivation. High level of xylanase production (135 IU gds(-1)) was observed when grown on wheat bran followed by maize powder (50 IU gds(-1)). The maximum xylanase (136 IU gds(-1)) production was occurred in wheat bran-to-moisture ratio of 1 : 1 at 72 h. The xylanase pretreated pulp samples of banana, silk cotton and cotton showed an increased brightness of 19.6, 11.6 and 7.9%, respectively. Conclusions: The enzyme-aided biobleaching results indicate that the xylanase has potential application in enhancing the brightness of nonwoody plant fibre pulp. Significance: This is the first report on biobleaching of banana fibres, silk cotton and cotton pulps using xylanase. The biobleaching results of secondary fibres are promising and can be transferred to paper mills, which utilize nonwoody plant fibres as a raw material for paper production.