Production of beta-xylanase by a Thermomyces lanuginosus MC 134 mutant on corn cobs and its application in biobleaching of bagasse pulp
2009
Kumar, K.S.(Durban University of Technology (South Africa)) | Manimaran, A. | Permaul, K. | Singh, S.
The production of hemicellulases by Thermomyces lanuginosus SK using oatspelts xylan was examined during submerged cultivation. A high level of extracellular xylanase (346 +- 10 U/ml) production was observed on the fifth day; however, accessory enzyme levels were low. T. lanuginosus SK was further subjected to UV and N-methyl-N-nitro-N-nitrosoguanidine mutagenesis. The T. lanuginosus MC 134 mutant showed a 1.5 fold increase in xylanase production on oatspelts xylan, compared to the wild type strain. Xylanase production was further enhanced to 3299 +- 95 U/ml by using corn cobs under optimized growth conditions. A reduction in xylanase production was observed in a 5 L fermenter. Also, the biobleaching efficiency of crude xylanase was evaluated on bagasse pulp, and a brightness of 46.07 +- 0.05% was observed with the use of 50 U of crude xylanase per gram of pulp. This brightness was 3.6 points higher than that of the untreated samples. Reducing sugars (25.78 +- 0.14 mg/g) and UV-absorbing lignin-derived compound values were considerably higher in xylanase-treated samples. T. lanuginosus MC 134 has a potential application in the pulp and paper industries.
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