Zhang Yan, Shi Junling, Gao Zhenhong, Yangwu Ruiming, Jiang Huanshi, Che Jinxin, Liu Yanlin
College of Food Science and Engineering, Northwest A&F University, 28 Xinong Road, Yangling, Shaanxi Province, 712100, China.
Appl Microbiol Biotechnol. 2015 Jun;99(11):4629-43. doi: 10.1007/s00253-015-6491-7. Epub 2015 Mar 25.
Phomopsis sp. XP-8 is an endophytic fungus that has the ability to produce pinoresinol diglucoside (PDG) in vitro and thus has potential application for the biosynthesis of PDG independent of plants. When cultivated in mung bean medium, PDG production was significantly improved and pinoresinol monoglucoside (PMG) and pinoresinol (Pin) were also found in the culture medium. In this experiment, starch, protein, and polysaccharides were isolated from mung beans and separately used as the sole substrate in order to explore the mechanism of fermentation and identify the major substrates that attributed to the biotransformation of PDG, PMG, and Pin. The production of PDG, PMG, and Pin was monitored using high-performance liquid chromatography (HPLC) and confirmed using HPLC-MS. Activities of related enzymes, including phenylalanine ammonia-lyase (PAL), trans-cinnamate 4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) were analyzed and tracked during the cultivation. The reaction system contained the compounds isolated from mung bean in the designed amount. Accumulation of phenylalanine, cinnamic acid, p-coumaric acid, PDG, PMG, and Pin and the activities of PAL, C4H, and 4CL were measured during the bioconversion. PMG was found only when mung bean polysaccharide was analyzed, while production of PDG and Pin were found when both polysaccharide and starch were analyzed. After examining the monosaccharide composition of the mung bean polysaccharide and the effect of the different monosaccharides had on the production of PMG, PDG, and Pin, galactose in mung bean polysaccharide proved to be the major factor that stimulates the production of PMG.
拟茎点霉属XP - 8是一种内生真菌，具有在体外产生松脂醇二葡萄糖苷（PDG）的能力，因此在不依赖植物的情况下，在PDG生物合成方面具有潜在应用价值。在绿豆培养基中培养时，PDG产量显著提高，且在培养基中还发现了松脂醇单葡萄糖苷（PMG）和松脂醇（Pin）。在本实验中，从绿豆中分离出淀粉、蛋白质和多糖，并分别用作唯一底物，以探究发酵机制并确定导致PDG、PMG和Pin生物转化的主要底物。使用高效液相色谱法（HPLC）监测PDG、PMG和Pin的产量，并通过HPLC - MS进行确认。在培养过程中分析并跟踪相关酶的活性，包括苯丙氨酸解氨酶（PAL）、反式肉桂酸4 - 羟化酶（C4H）和4 - 香豆酸 - CoA连接酶（4CL）。反应体系包含按设计量从绿豆中分离出的化合物。在生物转化过程中，测定苯丙氨酸、肉桂酸、对香豆酸、PDG、PMG和Pin的积累以及PAL、C4H和4CL的活性。仅在分析绿豆多糖时发现了PMG，而在分析多糖和淀粉时均发现了PDG和Pin的产生。在检测了绿豆多糖的单糖组成以及不同单糖对PMG、PDG和Pin产量的影响后，发现绿豆多糖中的半乳糖是刺激PMG产生的主要因素。
