富硒酵母的筛选优化及其对心肌肥大的影响

A selenium-rich yeast strain: screening, culture condition optimization, and protecting effect against myocardial hypertrophy

摘要:

【背景】宜春的温汤温泉是天然富硒温泉，同时也是富硒土壤区域。【目的】筛选优化富硒酵母并研究其对心功能的保护作用。【方法】实验选取了60个典型土壤样本，并通过筛选抗性平板获得了一种具有高硒富集能力的酵母菌株。显微镜和扫描电子显微镜观察表明，此酵母是一种典型的酵母菌株，通过18S测序鉴定为葡萄汁有孢汉逊酵母(Hanseniaspora uvarum)。实验进一步优化了亚硒酸钠的添加量、添加时间、发酵时间和温度，优化后酵母中的有机硒含量进一步升高。在发酵罐中进一步放大发酵后有机硒含量达到高水平，OD₆₀₀在56 h后高达132。为了研究富硒酵母的生理功能，实验通过阿霉素(doxorubicin, ADR)建立了心肌肥大小鼠模型。【结果】富硒酵母对改善心肌肥大有良好的效果，其机制可能与抗氧化和抗凋亡作用有关。【结论】筛选出一种高硒含量的酵母菌株。通过优化培养条件和5 L发酵罐的发酵，表明所获得的酵母具有良好的工业应用前景，并且这种富硒酵母具有良好的抗氧化活性。

Abstract:

[Background] The water and soil of Wentang hot spring in Yichun is rich in selenium. In this study, a selenium-rich yeast strain was isolated from this natural selenium-rich area. [Objective] To optimize the culture conditions of the selenium-rich yeast strain and study the protective effect of this strain on cardiac function. [Methods] Sixty typical soil samples were collected, from which a yeast strain with high selenium was screened out on the plate with antibiotics. Microscopy and scanning electron microscopy showed that the isolate was a typical yeast strain. The strain was identified by 18S sequencing as Hanseniaspora uvarum. The addition amount and time of sodium selenate, fermentation time, and fermentation temperature were optimized to improve the selenium content in this strain. The further scale-up fermentation in a fermenter showed a high level of organic selenium content, and the cell density (OD₆₀₀) reached 132 after 56 h. Furthermore, a mouse model of cardiac hypertrophy was established with doxorubicin to study the physiological function of selenium-rich yeast. [Results] The selenium-rich yeast strain alleviated myocardial hypertrophy, which may be related to its anti-oxidation and anti-apoptosis effects. [Conclusion] We successfully isolated a yeast strain with high selenium content. The culture condition optimization and scale-up fermentation in a 5-L fermenter showed that the obtained yeast strain had a broad industrial application prospect, and such selenium-rich yeast had a strong antioxidant activity.