大黄鱼鱼卵鱼露快速发酵过程中细菌多样性及PICRUSt基因功能预测

Bacterial diversity and PICRUSt gene functions during rapid fermentation of fish sauce made from large yellow croaker roe

为探究鱼露快速发酵过程中细菌多样性的变化,以大黄鱼鱼卵为研究对象,通过酶解和加曲的方式快速发酵鱼露,采用16S rDNA高通量测序技术分析大黄鱼鱼卵鱼露快速发酵过程中细菌群落结构的变化,并开展基因功能预测分析。结果显示,未灭菌组(K组)和灭菌组(M组)鱼露的优势菌门均为厚壁菌门和变形菌门。葡萄球菌属是鱼露发酵过程中的优势菌属,相对丰度高的菌属有链球菌属、糖芽孢杆菌属、类芽孢杆菌属和希瓦氏菌属。PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states)基因功能预测显示,鱼露细菌基因功能涉及遗传信息处理、代谢等6类一级生物代谢通路,以及辅助因子与维生素的代谢、能量代谢等35个二级功能层。M组鱼露在发酵第5、10天时的细菌组成与组内其他发酵时间的样本存在明显差异,这可能是因为M组发酵前期含有相对丰度较高的芽孢杆菌属及更为丰富的二级功能预测基因。在M组鱼露发酵后期,复合曲的加入使细菌菌落发生了改变。本研究结果可为筛选功能菌、改善鱼露品质提供依据。

To explore the changes of bacterial diversity during rapid fermentation of fish sauce,16S r DNA high-throughput sequen-cing technology and phylogenetic investigation of communities by reconstruction of unobserved states(PICRUSt)were applied to an-alyze the dynamics of bacterial community and predict gene functions during the fermentation of fish sauce based on large yellow croaker roe by adding protease or fermentative microorganism.The results showed that the dominant phyla in both unsterilized group K and sterilized group M were Firmicutes and Proteobacteria.Staphylococcus was the dominant genus during the fermentation,and Streptococcus,Saccharibacillus,Paenibacillus and Shewanella were relatively abundant.PICRUSt function prediction revealed that the bacterial gene in fish sauce involved in 6 primary biometabolic pathways and 35 sub-functions such as cofactor and vitamin me-tabolism and energy metabolism.In M group,the bacterial composition in fish sauce on either 5th or 10th day of fermentation was significantly different from that on other days,which may be the result of relatively higher abundance of Bacillus and secondary func-tion genes at the early fermentation stage.While at the late fermentation stage,the addition of fermentative microorganism altered the bacterial community in M group.The results provided a theoretical basis for the screening of functional bacteria and improved quality of fish sauce.