不同处理方式的大曲真菌群落差异分析

Comparison of Fungal Communities in Daqu with Different Treatments

为探究热风干燥工艺对贮存期大曲中真菌群落的影响,采用实时荧光定量聚合酶链式反应和Illumina MiSeq高通量测序技术分析和比较不同处理方式的大曲真菌群落的差异。结果表明不同处理方式大曲中的真菌18S rRNA基因拷贝数在1×10^(11)～4.5×10^(11) copies/g之间,ZR3拷贝数最大为4.5×10^(11) copies/g。不同处理大曲的优势真菌类群均为嗜热子囊菌属(Thermoascus)、根毛霉属(Rhizomucor)、曲霉菌属(Aspergillus)、假丝酵母属(Candida)。其中嗜热子囊菌属在大曲真菌群落中具有明显的优势,若要保持其优势,需提供曲库的贮存条件;实验室贮存环境相比于曲库更有利于曲霉菌属类的生长;干燥工艺后的环境更利于假丝酵母属类生长。大曲RG3(热风干燥处理的大曲在实验室条件下贮存2个月)的多样性指数较高,真菌群落有较大的变化,差异性明显;其中耐盐真菌(Wallemia)、丝衣霉菌属(Byssochlamys)、青霉菌属(Penicillium)、曲霉菌属(Aspergillus)是RG3区别于其他大曲的主要真菌群类;同时主成分分析看出大曲RG3落点相对较远,此类大曲有进一步研究的价值,为大曲热风干燥工业化应用提供指导。

In order to explore the effect of hot air drying on the fungal communities in Daqu during storage,qPCR and high-throughput sequencing were used to analyze and compare the fungal community structures in Daqu with different treatments.The results showed that the number of 18S rRNA gene copies of fungi in all Daqu samples was between 1×1011 and 4.5×1011 copies/g,and the maximum number of copies of ZR3 was 4.5×1011 copies/g.Thermoascu spp.,Rhizomucor spp.,Aspergillus spp.and Candida spp.were the dominant fungi in all tested samples.Among these,Thermoascus spp.was the most predominant and it remained predominant during storage in Daqu storehouse.Compared with the storehouse environment,the laboratory storage environment was more conducive to the growth of Aspergillus spp..Candida spp.grew better in dried Daqu.Besides,higher diversity indexes were observed in Daqu RG3 with hot air drying and subsequent laboratory storage for 2 months,as well as significant differences in the fungal communities,especially Wallemia spp.,Byssochlamys spp.,Penicillium spp.and Aspergillus spp..Furthermore,principal component analysis(PCA)showed that the drop point of Daqu RG3 was relatively far away from other samples.Hence,it is worth further study to provide guidance for the industrial application of hot air drying on Daqu.