Zhao Chen, Tian Xue-Mei, Wang Guang-Yuan, Song Ai-Rong, Liang Wen-Xing
Shandong Province Key Laboratory of Applied Mycology, School of Life Sciences, Qingdao Agricultural University, Qingdao, People's Republic of China.
Institute of Microbiology, P.O. Box 61, Beijing Forestry University, Beijing 100083, China; Shandong Provincial Key Laboratory of Applied Mycology, Qingdao Agricultural University, Qingdao 266109, China; College of Life Sciences, Qingdao Agricultural University, Qingdao, China.
Int J Med Mushrooms. 2016;18(7):621-30. doi: 10.1615/intjmedmushrooms.v18.i7.70.
A new Grifola frondosa mutant, M270, was successfully isolated for high production of exopolysaccharides (EPSs) using cosmic radiation-induced mutagenesis. We found that the mutant M270 had a clearer and thicker EPS layer (~10 µm) adhering to mycelia than those of its parent strain 265 after Congo red staining. In the 20-L batch fermentation for M270, 10.3 g/L of EPS and 17.9 g/L of dry mycelia biomass were obtained after 204 hours of fermentation. Furthermore, a main water-soluble fraction (EP1) in the EPS was purified from M270 and then confirmed to be heteroglycan-protein complex with 91% (w/w) total carbohydrates and 9% (w/w) total proteins. Four kinds of monosaccharide-D-mannose, D-glucosamine, D-glucose, and D-xylose-were detected in EP1 with a molar ratio of 17.6:1.8:100:2.5. The molecular mass of the main component in EP1 was 8.9 kDa. The EPS from M270 significantly inhibited the growth of sarcoma 180 solid tumors in mice. This G. frondosa M270 mutant could serve as a better candidate strain for polysaccharide production.
利用宇宙辐射诱变成功分离出一种新的灰树花突变体M270，其胞外多糖（EPS）产量高。刚果红染色后，我们发现突变体M270的菌丝体上附着的EPS层比其亲本菌株265的更清晰、更厚（约10 µm）。在20-L分批发酵M270时，发酵204小时后获得了10.3 g/L的EPS和17.9 g/L的干菌丝体生物量。此外，从M270中纯化出EPS中的一种主要水溶性组分（EP1），然后确认为杂聚糖-蛋白质复合物，总碳水化合物含量为91%（w/w），总蛋白质含量为9%（w/w）。在EP1中检测到四种单糖——D-甘露糖、D-葡萄糖胺、D-葡萄糖和D-木糖，摩尔比为17.6:1.8:100:2.5。EP1中主要成分的分子量为8.9 kDa。M270的EPS显著抑制小鼠肉瘤180实体瘤的生长。这种灰树花M270突变体可作为多糖生产的更好候选菌株。
