Department of Biobased Materials Science, Kyoto Institute of Technology, Kyoto, Japan.
Corporate Research & Business Division, Kaneka Corporation, Osaka, Japan.
J Appl Microbiol. 2021 Jun;130(6):1972-1980. doi: 10.1111/jam.14900. Epub 2020 Nov 9.
Aspergillus niger S17-5 produces two alkylitaconic acids, 9-hydroxyhexylitaconic acid (9-HHIA) and 10-hydroxyhexylitaconic acid (10-HHIA), which have cytotoxic and polymer building block properties. In this study, we characterized the production of 9-HHIA and 10-HHIA by addition of their expected precursor, caprylic acid, to a culture of A. niger S17-5, and demonstrated batch fermentation of 9-HHIA and 10-HHIA in a jar fermenter with DO-stat.
Production titres of 9-HHIA and 10-HHIA from 3% glucose in a flask after 25 days cultivation were 0·35 and 1·01 g l respectively. Addition of 0·22 g l of caprylic acid to a suspension of resting cells of A. niger S17-5 led to 32% enhancement of total 9-HHIA and 10-HHIA production compared to no addition. No enhancement of the production of 9-HHIA or 10-HHIA by the addition of oxaloacetic acid was observed. Addition of caprylic acid to the culture at mid-growth phase was more suitable for 9-HHIA and 10-HHIA production due to less cell growth inhibition by caprylic acid. DO-stat batch fermentation with 3% glucose and 14·4 g l of caprylic acid in a 1·5 l jar fermenter resulted in the production titres of 9-HHIA and 10-HHIA being 0·48 and 1·54 g l respectively after 10 days of cultivation.
Addition of caprylic acid to the culture of A. niger S17-5 enhances 9-HHIA and 10-HHIA production.
These results suggest that 9-HHIA and 10-HHIA are synthesized with octanoyl-CoA derived from caprylic acid, and that the supply of octanoyl-CoA is a rate-limiting step in 9-HHIA and 10-HHIA production. To the best of our knowledge, this is the first report regarding the fermentation of naturally occurring itaconic acid derivatives in a jar fermenter.
黑曲霉 S17-5 产生两种烷基衣康酸，9-羟基己基衣康酸（9-HHIA）和 10-羟基己基衣康酸（10-HHIA），具有细胞毒性和聚合物构建块特性。在这项研究中，我们通过向黑曲霉 S17-5 的培养物中添加其预期前体辛酸来表征 9-HHIA 和 10-HHIA 的产生，并在 DO-stat 控制下的摇瓶发酵器中证明了 9-HHIA 和 10-HHIA 的分批发酵。
在培养 25 天后，3%葡萄糖在瓶中的 9-HHIA 和 10-HHIA 的产量分别为 0.35 和 1.01 g/l。向黑曲霉 S17-5 休止细胞悬浮液中添加 0.22 g/l 的辛酸可使总 9-HHIA 和 10-HHIA 的产量分别比不添加时提高 32%。添加草酰乙酸对 9-HHIA 或 10-HHIA 的产生没有增强作用。在生长中期向培养物中添加辛酸更适合 9-HHIA 和 10-HHIA 的生产，因为辛酸对细胞生长的抑制作用较小。在 1.5 l 摇瓶发酵器中，以 3%葡萄糖和 14.4 g/l 辛酸进行 DO-stat 分批发酵，在培养 10 天后，9-HHIA 和 10-HHIA 的产量分别为 0.48 和 1.54 g/l。
向黑曲霉 S17-5 的培养物中添加辛酸可增强 9-HHIA 和 10-HHIA 的产生。
这些结果表明，9-HHIA 和 10-HHIA 是由辛酸衍生的辛酰辅酶 A 合成的，而辛酰辅酶 A 的供应是 9-HHIA 和 10-HHIA 产生的限速步骤。据我们所知，这是关于在摇瓶发酵器中发酵天然存在的衣康酸衍生物的第一份报告。
