Department of Microbiology, Vidyasagar University, Midnapore 721102, West Bengal, India.
Appl Biochem Biotechnol. 2012 Jul;167(5):1208-19. doi: 10.1007/s12010-012-9556-4. Epub 2012 Jan 26.
Recycling of civic paper waste by enzyme-based technology is nowadays a point of much concern for pollution-less green environment. In this study, the deinking effectiveness of purified xylanase from a newly isolated bacterium was evaluated for recycling of laser jet paper waste. A potent xylanases-producing bacterium from the microbial consortia of termite gut was isolated, which was further identified on the basis of 16S rRNA sequence as Bacillus sp. CKBx1D. In submerged fermentation condition, the isolate produced the highest level of xylanase (480 U/ml) at 36 h of growth. The extracellular xylanase system comprises of three distinct isozymes (est. Mw 35.28, 28.63, 18.94 kDa). The deinking of laser printed paper waste was performed using the purified enzyme mixture. Whole operational parameters were optimized using the Response Surface Methodology; it was found that at pH 6.8 with 47.2 h of continuous shaking at constant temperature of 35 °C, enzymes showed best deinking activity. After enzyme treatment, the physical properties of the pulp like brightness and ERIC (effective residual ink content) values were enhanced, whereas the pulp opacity was more reduced than the control treatment. Hence, the bacterial isolate and its xylanolytic enzyme system could efficiently be used in recycling paper waste as deinking agent.
现如今，通过基于酶的技术回收民用纸张废弃物是人们关注的一个焦点，因为这对无污染的绿色环境非常重要。在这项研究中，评估了从新分离的细菌中提取的木聚糖酶对激光打印纸废物回收的脱墨效果。从白蚁肠道微生物共生体中分离出一种产木聚糖酶能力很强的细菌，根据 16S rRNA 序列进一步鉴定为芽孢杆菌 CKBx1D。在液体发酵条件下，该分离株在 36 小时的生长过程中产生了最高水平的木聚糖酶（480 U/ml）。细胞外木聚糖酶系统由三种不同的同工酶组成（估计分子量为 35.28、28.63 和 18.94 kDa）。使用纯化的酶混合物对激光打印纸废物进行脱墨处理。使用响应面法优化了整个操作参数；结果发现，在 pH 值为 6.8、持续 47.2 小时、在 35°C 的恒定温度下连续摇动时，酶表现出最佳的脱墨活性。酶处理后，纸浆的物理性能（如白度和 ERIC 值）得到了提高，而纸浆不透明度的降低程度比对照处理更大。因此，该细菌分离株及其木聚糖酶系统可以有效地用作脱墨剂来回收纸张废弃物。
