Adipic acid production from lignin
Adipic acid production from lignin
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DOI：
10.1039/c4ee03230f
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发表时间：
2015-01-01
影响因子：
32.5
通讯作者：
Beckham, Gregg T.
中科院分区：
文献类型：
--
作者：
Vardon, Derek R.;Franden, Mary Ann;Beckham, Gregg T.
木质素是存在于植物细胞壁中的烷基-芳香族聚合物，用于防御、结构和水分运输。尽管表现出高能量含量，但由于其固有的异质性和可降解性，木质素通常被指定用于现代生物精炼厂中的燃烧，而纤维素和半纤维素被转化为可再生燃料和化学品。然而，第三代生物精炼厂的可行性至关重要，以使木质素与多糖一起增值。为此，我们采用代谢工程、分离和催化将木质素衍生的物质转化为顺式，顺式-粘康酸，随后氢化为己二酸，后者是最广泛生产的二羧酸。首先，恶臭假单胞菌KT 2440被代谢工程化以将木质素衍生的芳族化合物汇集成顺式，顺式-粘康酸酯，这是原子有效的生物化学转化。将该工程菌株用于分批补料生物培养，以证明在78.5小时内来自模型木质素衍生化合物的13.5 g L-1的顺式，顺式-粘康酸盐滴度。通过活性炭处理和结晶（5 ℃，pH 2），以高纯度（>97%）和产率（74%）回收顺式，顺式-粘康酸。Pd/C是一种高活性催化剂，催化顺，顺粘康酸加氢合成己二酸，具有较高的转化率（>97%）和选择性（>97%）。在表面反应控制条件下（24 ° C，24巴，乙醇溶剂），纯化的顺式，顺式-粘康酸在Pd/C上表现出23-30 s（-1）的转换频率，表观活化能为70 kJ mol（-1）。最后，用在生物质衍生的富含木质素的流上生长的工程化恶臭假单胞菌生产顺式，顺式-粘康酸酯，展示了将木质素价值化为重要商品化学品的综合策略。
Lignin is an alkyl-aromatic polymer present in plant cell walls for defense, structure, and water transport. Despite exhibiting a high-energy content, lignin is typically slated for combustion in modern biorefineries due to its inherent heterogeneity and recalcitrance, whereas cellulose and hemicellulose are converted to renewable fuels and chemicals. However, it is critical for the viability of third-generation biorefineries to valorize lignin alongside polysaccharides. To that end, we employ metabolic engineering, separations, and catalysis to convert lignin-derived species into cis, cis-muconic acid, for subsequent hydrogenation to adipic acid, the latter being the most widely produced dicarboxylic acid. First, Pseudomonas putida KT2440 was metabolically engineered to funnel lignin-derived aromatics to cis, cis-muconate, which is an atom-efficient biochemical transformation. This engineered strain was employed in fed-batch biological cultivation to demonstrate a cis, cis-muconate titer of 13.5 g L-1 in 78.5 h from a model lignin-derived compound. cis, cis-Muconic acid was recovered in high purity (>97%) and yield (74%) by activated carbon treatment and crystallization (5 degrees C, pH 2). Pd/C was identified as a highly active catalyst for cis, cis-muconic acid hydrogenation to adipic acid with high conversion (>97%) and selectivity (>97%). Under surface reaction controlling conditions (24 degrees C, 24 bar, ethanol solvent), purified cis, cis-muconic acid exhibits a turnover frequency of 23-30 s(-1) over Pd/C, with an apparent activation energy of 70 kJ mol(-1). Lastly, cis, cis-muconate was produced with engineered P. putida grown on a biomass-derived, lignin-enriched stream, demonstrating an integrated strategy towards lignin valorization to an important commodity chemical.