响应面法优化富硒粗毛纤孔菌菌丝生长培养基成分

本研究考察了粗毛纤孔菌对无机硒的耐受度,并通过响应面法对富硒粗毛纤孔菌菌丝生长培养基成分进行了优化。以粗毛纤孔菌菌丝生长速度为指标,通过单因素实验及Box-Behnken响应面优化,确定该菌菌丝富硒培养基的最佳组成成分,并通过电感耦合等离子体质谱法(ICP-MS)对该菌菌丝硒富集量进行检测。结果表明,粗毛纤孔菌菌丝的生长情况受外源硒影响较大,当硒浓度≥37.25 mg/L时,该菌菌丝生长开始受到显著的抑制(P<0.05),其对硒的最大耐受浓度约为298~596 mg/L;经响应面法优化得到富硒粗毛纤孔菌菌丝生长最优培养基成分为:麸皮56.8 g/L、葡萄糖49 g/L、Se 22.4 mg/L、MgSO₄ 0.75 g/L、KH₂PO₄ 1 g/L、V_B1 1 mg/L、琼脂15 g/L,在此条件下,富硒粗毛纤孔菌实际菌丝生长速度达到8.41 mm/d,与未优化对照组相比,菌丝生长速度提高了0.965倍,且硒富集量达到31.584 μg/g。本研究获得了富硒粗毛纤孔菌菌丝生长培养基最优配方,为富硒粗毛纤孔菌菌丝体的大量制备、富硒粗毛纤孔菌子实体的栽培及其它后续研究提供了理论依据。

Optimizing of the Medium Composition for Mycelial Growth of Selenium-enriched Inonotus hispidus by Response Surface Methodology

In this study, the tolerance level of I. hispidus to inorganic Se was investigated. And the culture mediumfor mycelial growth of Se-enriched I. hispidus was optimized using response surface method (RSM). To determine the optimal components of the Se-rich medium, the effect of single factor to mycelial growth of I. hispidus (average mycelium growth rate was calculated as measurement index) was initially identified respectively. Box-Behnken design was then used to create a model for optimizing the Se-rich medium components. Meanwhile, Se content in the mycelia of Se-enriched I. hispidus was detected by ICP-MS. The results showed that the mycelial growth of I. hispidus was greatly influenced by the concentration of exogenous Se. The growth rate of I. hispidus began to be inhibited significantly at 37.25 mg/L Se concentration (P<0.05). And the maximal tolerant concentration of I. hispidus to Se was approximately at 298~596 mg/L. The suitable Se concentration, principal component and supplementary carbon source were selected and adjusted by the model, which predicted the significant effect could be obtained when the Se-rich medium contained bran, glucose, Se, MgSO₄, KH₂PO₄, V_B1 and agar at 56.8, 49, 2.24×10-2, 0.75, 1, 1×10-3 and 15 g/L, respectively. Verification of this recipe resulted in the average mycelium growth rate at 8.41 mm/d, which was 0.965 times higher than that cultivated by using the modified PDA medium with equivalent Se addition. And Se content in the mycelia of Se-enriched I. hispidus reached 31.584 μg/g. In this study, the optimal recipe of medium for mycelial growth of Se-enriched I. hispidus was obtained, which provided a basic information for producing mycelia and fruiting bodies of selenized I. hispidus or other subsequent studies.