Enhanced Biodegradation of Lignin by Laccase through HOBT Mediator: Mechanistic Studies Supported by FTIR and GCMS Studies

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• 作者：T. Senthilvelan ; J. Kanagaraj ; Rames C. Panda
• 关键词：Lignin ; Degradation by laccase ; UV ; TGA ; DSC ; FTIR ; GCMS studies ; COD ; TOC reductions
• 刊名：Environmental Processes
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：4
• 期：1
• 页码：201-217
• 全文大小：
• 刊物类别：Environmental Science and Engineering; Environmental Management; Waste Management/Waste Technology;
• 刊物主题：Environmental Science and Engineering; Environmental Management; Waste Management/Waste Technology; Water Quality/Water Pollution;
• 出版者：Springer International Publishing
• ISSN：2198-7505
• 卷排序：4

文摘

In the present investigation, a suitable technology for biodegradation of lignin using laccase with the help of mediator 1-hydroxybenzotriazole (HOBT) for enhancing the degradation has been attempted. The results showed that biodegradation of lignin at the level of 91–98% could be achieved for different concentrations of laccase with optimized parameters of 5.0 mM HOBT at pH 7.0 and temperature at 32°C within 24 h. UV analysis confirmed the disappearance of the original peak indicating the break-down of aromatic content of lignin to smaller components. Thermo-gravimetric and differential scanning calorimetric (TGA-DSC) analysis showed thermal stability of the compound while decomposing through six steps, at 137, 257, 417, 586, 699 and 759°C, leaving a final residue of about 46%. The DSC experiment recorded the starting of thermal denaturing temperature as 83.83°C. Results of Fourier transform infrared (FTIR) analysis detected the presence of hydroxyl group (at 2939–3420 cm−1), C=C, C-H, C-N and C-S stretching at 1505–1595 cm−1, 1212 cm−1, 2597–3272 cm−1, indicating presence of phenolic and carboxylic acid groups during degradation. Gas Chromatography Mass Spectrometry (GCMS) confirmed the formation of various intermediates. Reduction of chemical oxygen demand (COD) and total organic carbon (TOC) at the level of 84 and 80% were observed, respectively. The present investigation is very useful in treating wastewater containing lignin.