黑木耳的富硒发酵

本实验以亚硒酸钠（Na2 SeO3）为硒源对黑木耳进行富硒发酵,以获得富硒黑木耳发酵液,为有机硒多糖等开发利用提供依据.用3种不同碳氮源培养基26℃于200rpm进行液体发酵,在不同时间测定黑木耳菌丝体多糖含量和生物量,确定了最优培养基（每升）为葡萄糖20g,豆饼粉5g,硫酸镁0.5g,磷酸二氢钾2g.在优选培养基中通过添加不同浓度的亚硒酸钠对黑木耳进行富硒发酵.结果与不添加亚硒酸钠黑木耳发酵液相比,在硒浓度为10-50mg/L时,黑木耳菌丝体的硒含量和生物量及发酵液多糖含量均随硒浓度的增加而提高;在50mg/L时,硒含量、生物量和多糖含量达最高,分别为10.48μg/g、9.37g和L20.3g/L;当亚硒酸钠浓度高于50mg/L时,菌丝体硒含量降低,生物量、多糖含量亦下降.结果表明,黑木耳具有较好富硒能力,但培养基中亚硒酸钠的浓度会影响发酵液中多糖含量和黑木耳菌丝体的富硒效果.与不添加亚硒酸钠黑木耳相比,添加适量亚硒酸钠有利于黑木耳菌丝对硒的吸收利用,并可促进黑木耳生长和多糖含量的提高;但过量添加,则可抑制黑木耳生长并降低多糖含量和对硒的利用率.

Fermentation of enriched-selenium of black fungus

The test was fermentation of enriched-Selenium of black fungus. It was carried by adding sodium selenite （Na2SeOa） as Selenium source. This provided basis for the develop- ment and utilization of organic selenium polysaccharide, etc. We used three different carbon and nitrogen cultures at 26℃, 200 rpm for fermented liquid. Accord to polysaccharide content and biomass at different time, we determined optimal medium （per litre） of glucose 20g, bean cake powder 5g, magnesium sulfate 0.5g, potassium dihydrogen phosphate 2g. The enriched- Selenium fermentation of black fungus was carried out by adding different concentrations of sodium selenite in the optimal medium. It compared with no adding sodium selenite of black fungus. The results showed that the Selenium content, biomass of mycelium and polysaccha- ride content in the fermented liquid increased along with selenium concentration between 10--
50mg/L. The highest value was 50mg/L with 10.48μg/g, 9.37g/L and 20.3g/L respective- ly. When selenium concentration was more than 50mg/L they decreased on the contrary. Re- sults expressed black fungus had a good ability to enriched-Selenium. But the selenium con- centration in the fermented liquid affected enriched-Selenium effect, growth of mycelium and polysaecharide content. If appropriate amount of sodium selenium was added, it was helpful to absorb sodium selenium for myeelium, promote myeelium growth and improve polysaccha- ride content. If the amount of sodium selenium was more than the appropriate amount, they can be inhibited.