Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan E-mail:
Department of Biology, Karadeniz Technical University, Trabzon, Turkey.
Water Sci Technol. 2022 Jan;85(1):420-432. doi: 10.2166/wst.2021.610.
Lignin is a major by-product of pulp and paper industries, and is resistant to depolymerization due to its heterogeneous structure. Degradation of lignin can be achieved by the use of potential lignin-degrading bacteria. The current study was designed to evaluate the degradation efficiency of newly isolated Bacillus altitudinis SL7 from pulp and paper mill effluent. The degradation efficiency of B. altitudinis SL7 was determined by color reduction, lignin content, and ligninolytic activity from degradation medium supplemented with alkali lignin (3 g/L). B. altitudinis SL7 reduced color and lignin content by 26 and 44%, respectively, on the 5th day of incubation, as evident from the maximum laccase activity. Optimum degradation was observed at 40 °C and pH 8.0. FT-IR spectroscopy and GC-MS analysis confirmed lignin degradation by emergence of the new peaks and identification of low-molecular-weight compounds in treated samples. The identified compounds such as vanillin, 2-methyoxyhenol, 3-methyl phenol, oxalic acid and ferulic acid suggested the degradation of coniferyl and sinapyl groups of lignin. Degradation efficiency of B. altitudinis SL7 towards high lignin concentration under alkaline pH indicated the potential application of this isolate in biological treatment of the lignin-containing effluents.
木质素是制浆造纸工业的主要副产物，由于其异质结构，难以进行解聚。可以利用潜在的木质素降解菌来降解木质素。本研究旨在评估从纸浆和造纸厂废水中分离出的新菌株高山芽孢杆菌 SL7 的降解效率。通过在含有碱木质素（3 g/L）的降解培养基中添加 B. altitudinis SL7 来测定其降解效率。在第 5 天的培养过程中，B. altitudinis SL7 使颜色和木质素含量分别减少了 26%和 44%，这可以从最大漆酶活性中看出。在 40°C 和 pH 8.0 时观察到最佳降解。傅里叶变换红外光谱和 GC-MS 分析证实了木质素的降解，新峰的出现和处理样品中低分子量化合物的鉴定证实了这一点。鉴定出的化合物，如香草醛、2-甲氧基苯酚、3-甲基苯酚、草酸和阿魏酸，表明木质素的松柏基和丁香基的降解。B. altitudinis SL7 在碱性 pH 下对高浓度木质素的降解效率表明该分离物在含木质素废水的生物处理中的潜在应用。
