Biovalorization of lignin-derived aromatic monomers such as ferulic acid (FA) has attracted considerable interest. The cold-adapted strain Paraburkholderia aromaticivorans AR20-38 converts FA to the value-added product vanillic acid (VA), without further VA degradation. The efficiency of the bioconversion of FA to VA was optimized by studying culture conditions. Various cultivation parameters (agitation, temperature, FA concentration, nutrient supplementation) were assessed to increase biomass production and shorten the cultivation time, while obtaining high VA production yields. The fate of the intermediate vanillin was also studied. Lignin monomers and degradation products (FA, vanillin, VA) were quantified via UV/Vis-HPLC. Full bioconversion of 5 mM FA occurred over a broad temperature range of 5–30 °C. Concentrations up 30 mM FA were utilized as the sole carbon source at 20 °C. Molar VA yields (> 90%) produced from 5 to 12.5 mM FA and from 15 to 17.5 mM FA (82–87%) were not significantly different at 10 °C and 20 °C. The supplementation of the mineral medium with monosaccharides (glucose, fructose, mannose) and/or N-rich complex compounds (yeast extract, casamino acids) resulted in high biomass production, accelerated FA bioconversion, and high molar yields (96–100%). The presence of the N-rich compounds alone or in combination with glucose reduced the incubation time necessary to convert FA to VA. Vanillin, formed as an intermediate during FA degradation, was consumed and converted to VA before FA metabolization, when added in combination with FA. Vanillin bioconversion was significantly accelerated in the presence of glucose. The variation of culture conditions improved the efficiency of the studied strain to convert FA via vanillin to VA and demonstrated remarkable FA bioconversion under varying environmental conditions, especially temperature, substrate concentration, and nutrient availability, which is of importance for potential future application.

中文翻译：

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冷适应的 Paraburkholderia aromaticivorans AR20-38 将阿魏酸和香草醛生物转化为香草酸：培养条件的影响

木质素衍生的芳香族单体如阿魏酸 (FA) 的生物价值化引起了相当大的兴趣。冷适应菌株 Paraburkholderia aromaticivorans AR20-38 将 FA 转化为增值产物香草酸 (VA)，而 VA 没有进一步降解。通过研究培养条件优化了 FA 向 VA 的生物转化效率。评估了各种培养参数（搅拌、温度、FA 浓度、营养补充）以增加生物量产量并缩短培养时间，同时获得高 VA 产量。还研究了中间体香兰素的命运。木质素单体和降解产物（FA、香兰素、VA）通过 UV/Vis-HPLC 进行量化。5 mM FA 的完全生物转化发生在 5–30 °C 的宽温度范围内。浓度高达 30 mM FA 被用作 20 °C 下的唯一碳源。从 5 到 12.5 mM FA 和从 15 到 17.5 mM FA (82–87%) 产生的摩尔 VA 产率 (> 90%) 在 10 °C 和 20 °C 下没有显着差异。用单糖（葡萄糖、果糖、甘露糖）和/或富含 N 的复杂化合物（酵母提取物、酪蛋白氨基酸）补充矿物培养基导致高生物量生产、加速 FA 生物转化和高摩尔产量 (96–100%) . 富氮化合物单独存在或与葡萄糖联合存在减少了将 FA 转化为 VA 所需的孵育时间。当与 FA 组合添加时，香兰素在 FA 降解过程中作为中间体形成，在 FA 代谢前被消耗并转化为 VA。在葡萄糖存在下，香草醛的生物转化显着加速。