一株耐盐解磷真菌的筛选、鉴定及其发酵优化

Isolation, Identification and Fermentation Optimization of a Halotolerant Strain with Phosphate-solubilizing Activity

从黄河三角洲盐碱土壤中分离到一株真菌PSF2,该菌具有极强的溶磷能力,在改良孟金娜液体培养基中培养72 h,发酵液中的可溶性磷含量高达1042.0 mg L-1,且兼具耐盐特性,最高可以耐受12.5%的盐浓度。经形态观察及ITS序列分析,初步确定该菌株为草酸青霉(Penicillium oxalicum),Gen Bank登录号为KJ957935。在单因素试验基础上,采用正交试验设计对菌株PSF2的发酵条件进行了优化,结果表明菌株PSF2的最佳培养基组成是蔗糖15 g L-1、尿素0.14 g L-1、Na Cl 3.0%,p H 9.0。进一步研究表明,在含盐量0.45%的土壤中添加PSF2,培养20 d,土壤中有效磷含量可增加20.9%。

A phosphate-solubilizing strain PSF 2 was isolated from saline soil, which could produce 1042.0 mg L-1soluble phosphate after 72 h cultivation, combining additional salt resistance properties as well. Based on morphological characters and internal transcribed spacer(ITS) sequence analysis, it was identified as Penicillium oxalicum(Gen Bank Accession No. KJ9579353). The optimization of fermentation conditions was investigated by the single factor tests and the orthogonal design method. The optimal composition of the culture medium was recognized as follows: sucrose 15 g L-1, urea 0.14 g L-1, Na Cl 3.0%, p H 9. Phosphate-solubilizing experiments showed that strain PSF2 could enhance the soluble phosphate content by 20.9% after 20 days in the soil with 0.45% of salinity.