Chen Gong, Bei Qi, Shi Kan, Tian Xiaofei, Wu Zhenqiang
School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.
Dongguan Tianyi Biotechnology Co. Ltd.,, Dongguan, 523000, People's Republic of China.
AMB Express. 2017 Dec;7(1):24. doi: 10.1186/s13568-017-0327-z. Epub 2017 Jan 23.
Extractive fermentation in a nonionic surfactant aqueous solution provides a promising and efficient method to produce Monascus pigments. The behaviour of pigment secretion during the extractive cultivation was investigated in the present work. The results revealed that the secretion of intracellular pigment was limited by its saturation concentration in the nonionic surfactant aqueous solution. The intracellular pigment was completely extracted to the outside of the cell at a low cell density and high concentration of Triton X-100 (TX) in fermentation broth; otherwise, a restriction for pigment extraction would occur. The decrement of the intracellular orange and yellow pigments was inconsistent with the increment of extracellular pigments with an increase in the TX concentration. It could be inferred that the intracellular orange pigment was converted to extracellular yellow pigment during the transmembrane secretion process, which might be attributed to the enzyme catalysis in the non-aqueous phase solution. This study helps explain the mechanism of variation of pigment characteristic and extraction capacity in extractive fermentation.
在非离子表面活性剂水溶液中进行萃取发酵为生产红曲色素提供了一种有前景且高效的方法。本研究考察了萃取培养过程中色素分泌的行为。结果表明，细胞内色素的分泌受其在非离子表面活性剂水溶液中的饱和浓度限制。在发酵液中细胞密度较低且Triton X-100（TX）浓度较高时，细胞内色素可完全被萃取到细胞外；否则，会出现色素萃取受限的情况。随着TX浓度的增加，细胞内橙色和黄色色素的减少与细胞外色素的增加不一致。可以推断，在跨膜分泌过程中细胞内橙色色素转化为细胞外黄色色素，这可能归因于非水相溶液中的酶催化作用。本研究有助于解释萃取发酵中色素特性和萃取能力变化的机制。
