Sridevi A, Sandhya A, Ramanjaneyulu G, Narasimha G, Devi P Suvarnalatha
Department of Applied Microbiology, Sri Padmavathi Mahila Visvavidyalayam, Tirupati, AP, India.
Department of Microbiology, Sri Krishnadevaraya University, Anantapur, AP, India.
3 Biotech. 2016 Dec;6(2):165. doi: 10.1007/s13205-016-0480-0. Epub 2016 Aug 11.
Xylanase is a hemicellulase enzyme that catalyses the hydrolysis of xylan to xylose which is widely used in processing of feed, pulp and paper. It is produced by many microorganisms especially filamentous fungi like Trichoderma and Aspergillus. A potential xylanolytic fungal isolate Aspergillus niger was isolated from forest soils of Tirumala, AP, India, and its crude enzyme was checked for its potential in paper bleaching. Under submerged fermentation, production of xylanase, cellulase, biomass, total protein and sugar released were analysed after 7 days of incubation at room temperature. Maximum enzyme activity was recorded on the fifth day of incubation, biomass after the seventh day, total protein and sugar released on the sixth day of incubation. Enzyme pretreatment of paper reduced 3.5 points in kappa number, 3.1 points increase in brightness and removal of chromophores and hydrophobic compounds. The FTIR and SEM analysis of enzyme-treated sample had shown modification in surface morphology and functional groups. These results clearly demonstrated that the xylanase produced by A. niger was effective as a pulp biobleaching agent which can be used on an industrial scale.
木聚糖酶是一种半纤维素酶，可催化木聚糖水解为木糖，广泛应用于饲料、纸浆和造纸加工中。许多微生物都能产生木聚糖酶，尤其是像木霉和曲霉这样的丝状真菌。从印度安得拉邦蒂鲁马拉的森林土壤中分离出一种具有潜在木聚糖分解能力的真菌菌株黑曲霉，并检测了其粗酶在纸张漂白方面的潜力。在深层发酵条件下，在室温培养7天后，分析木聚糖酶、纤维素酶、生物量、总蛋白和释放的糖的产量。在培养的第五天记录到最大酶活性，第七天记录到生物量，第六天记录到总蛋白和释放的糖。对纸张进行酶预处理可使卡伯值降低3.5个点，亮度增加3.1个点，并去除发色团和疏水化合物。对酶处理样品的傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）分析表明，其表面形态和官能团发生了变化。这些结果清楚地表明，黑曲霉产生的木聚糖酶作为一种纸浆生物漂白剂是有效的，可用于工业规模。
