Xylanase production by Paenibacillus campinasensis BL11 and its pretreatment of hardwood kraft pulp bleaching.

Production of a single component 41 kDa xylanase from Paenibacillus campinasensis BL11 was conducted under various pH and temperature at the shake flask level. Alternative carbon and nitrogen sources were also evaluated. Up to 10.5 IU/mL and 29.39 IU/mg specific activity of xylanase in crude extract was obtained at 24 h, 37 °C, pH 8. In addition, same level of xylanase productions was also obtained on rice husk and rice straw at 2 days of incubation. Relative xylanase activities of 56.8% and 51.9% were found after 4 h incubation in pH 7 and pH 9 at 65 °C, respectively. Xylanase pretreatments (2.5 IU per gram of oven-dry pulp) increased brightness (as much as 4.4 and 3.9%) and viscosity (as much as 0.5 and 0.3 cP) of pulp after full chlorine dioxide bleaching for untreated and oxygen delignified hardwood kraft pulp. Increased benefits of pretreatment were found with increasing xylanase dosage and pretreatment time.