黑皮鸡枞菌菌丝体发酵富硒条件优化及菌丝体多糖抗氧化活性研究

Optimization of selenium-enriched fermentation conditions in Oudemansiella raphanipes mycelium and study on the antioxidant activities of mycelium polysaccharides

中文关键词:  黑皮鸡枞菌  菌丝体发酵  菌丝体多糖  亚硒酸钠  抗氧化活性

英文关键词:Oudemansiella raphanipes  mycelium fermentation  mycelium polysaccharide  sodium selenite  antioxidant activity

中文摘要:

      目的 优化黑皮鸡枞菌(Oudemansiella raphanipes, O. raphanipes)菌丝体发酵条件, 考查其富硒规律及菌丝体多糖的体外抗氧化活性。方法 以菌丝体干重、菌丝体多糖含量和硒利用率为主要考察指标, 分别考察外源硒浓度和发酵条件对黑皮鸡枞菌菌丝体发酵富硒的影响。以3种自由基清除率为指标, 考察菌丝体多糖及富硒菌丝体多糖的体外抗氧化能力。结果 黑皮鸡枞菌菌丝体富硒的最佳条件为: 硒元素添加量5 mg/L、发酵温度25℃、装液量250 mL (500 mL三角瓶)、发酵起始pH 7.0。在该条件下, 黑皮鸡枞菌的生物量、菌丝体多糖含量、硒利用率分别为(7.68±0.48) g/L、(3.82±0.24)%和(9.28±2.11)%。当富硒菌丝体多糖质量浓度为0.7 mg/L时, 其对羟自由基、超氧阴离子自由基和1,1-二苯基-2-三硝基苯肼(1,1-diphenyl- 2-picrylhydrazyl, DPPH)自由基的清除率分别为(49.05±1.94)%、(52.43±3.05)%和(63.87±2.95)%, 分别比对照组(不添加硒)高80.84%、7.75%和34.01%。结论 低浓度硒(5 mg/L)可以促进菌丝体生长及菌丝体多糖的累积, 但高浓度硒(≥15 mg/L)会对菌丝体生长和菌丝体多糖累积产生抑制。硒利用率主要受菌丝体产量及菌丝体硒含量的影响。通过富硒培养, 可以提高菌丝体多糖的抗氧化性。

英文摘要:

      Objective To optimize the fermentation conditions for Oudemansiella raphanipes (O. raphanipes) mycelial, and investigate the rule of selenium enrichment and antioxidant activity of mycelium polysaccharides in vitro. Methods According to mycelium dry weight, mycelium polysaccharide content, and selenium utilization rate, the effects of exogenous selenium concentration and fermentation conditions on selenium enrichment of O. raphanipes mycelium fermentation were investigated. The in vitro antioxidant capacity of mycelium polysaccharides and selenium- enriched mycelium polysaccharides were investigated with the scavenging rates of 3 kinds of radicals as the indexes. Results The optimal conditions for selenium enrichment of O. raphanipes were: 5 mg/L of selenium, fermentation temperature 25℃, liquid volume 250 mL/500 mL, and initial fermentation pH of 7.0. Under the optimal conditions, the biomass, polysaccharide content, and selenium utilization efficiency of the O. raphanipes were (7.68±0.48) g/L, (3.82±0.24)%, and (9.28±2.11)%, respectively. When the mass concentration of selenium- enriched polysaccharides was 0.7 mg/L, the scavenging rates of hydroxyl radicals, superoxide anion radicals, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were (49.05±1.94)%, (52.43±3.05)%, and (63.87±2.95)%, respectively, which were 80.84%, 7.75%, and 34.01% higher than the control group (without selenium addition). Conclusion Low concentration of selenium (5 mg/L) can promote mycelium growth and polysaccharides accumulation, and high concentration of selenium (≥15 mg/L) can inhibite mycelia growth and mycelia polysaccharide accumulation. The utilization rate of selenium is mainly affected by mycelium biomass and selenium content of the mycelium. The antioxidant activities of mycelium polysaccharides were improved by selenium-enriched culture.