Cheng Kuan-Chen, Hsiao Hsiang-Chun, Hou Yu-Chen, Hsieh Chang-Wei, Hsu Hsien-Yi, Chen Hung-Yueh, Lin Shin-Ping
Graduate Institute of Food Science and Technology, National Taiwan University, 1 Roosevelt Rd., Sec. 4, Taipei 10617, Taiwan.
Institute of Biotechnology, National Taiwan University, 1 Roosevelt Rd., Sec. 4, Taipei 10617, Taiwan.
Antioxidants (Basel). 2022 Apr 26;11(5):849. doi: 10.3390/antiox11050849.
Violacein has attracted increasing attention due to its various biological activities, such as antibacterial, antifungal, antioxidative, and antitumor effects. To improve violacein production, formic acid (FA) was added to a culture medium, which resulted in a 20% increase (1.02 g/L) compared to the no-FA-addition group (0.85 g/L). The use of a stirred-tank bioreactor system also improved violacein production (by 0.56 g/L). A quorum-sensing (QS)-related gene () was induced by FA treatment, which revealed that the mechanism induced by FA utilized regulation of the gene to induce the gene cluster for violacein production. To analyze the antioxidative properties of the violacein produced, 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) scavenging tests were conducted, and results reveal that the values of the 50% inhibitory concentration (IC) of DPPH and ABTS were 0.286 and 0.182 g/L, respectively. Violacein also showed strong inhibitory activity against Gram-positive bacteria ( and ). In summary, this study found that the addition of formic acid can promote QS of , thereby promoting the synthesis of violacein. Subsequently, the promoting effect was also evaluated in a bioreactor system. These findings will be helpful in establishing an economically beneficial production model for violacein in future work.
由于其多种生物活性，如抗菌、抗真菌、抗氧化和抗肿瘤作用，紫菌素已引起越来越多的关注。为了提高紫菌素的产量，将甲酸（FA）添加到培养基中，与未添加FA的组（0.85 g/L）相比，产量提高了20%（达到1.02 g/L）。使用搅拌罐生物反应器系统也提高了紫菌素的产量（提高了0.56 g/L）。FA处理诱导了一个与群体感应（QS）相关的基因（），这表明FA诱导的机制利用该基因的调控来诱导紫菌素生产的基因簇。为了分析所生产紫菌素的抗氧化特性，进行了2,2-二苯基-1-苦基肼基水合物（DPPH）和2,2'-偶氮二（3-乙基苯并噻唑啉-6-磺酸）（ABTS）清除试验，结果显示DPPH和ABTS的50%抑制浓度（IC）值分别为0.286和0.182 g/L。紫菌素对革兰氏阳性菌（和）也表现出较强的抑制活性。总之，本研究发现添加甲酸可促进的群体感应，从而促进紫菌素的合成。随后，在生物反应器系统中评估了这种促进作用。这些发现将有助于在未来的工作中建立一种经济上有益的紫菌素生产模型。
