为揭示传统固态发酵鲊鱼发酵过程中细菌菌群结构演变规律及自然发酵本质,采用Illmina Hi Seq高通量测序技术分析发酵0~180 d共10个时间点的细菌群落结构的变化,同时对其质构特征、氨基酸组分、脂肪酸组分的变化规律进行分析。结果表明:...为揭示传统固态发酵鲊鱼发酵过程中细菌菌群结构演变规律及自然发酵本质,采用Illmina Hi Seq高通量测序技术分析发酵0~180 d共10个时间点的细菌群落结构的变化,同时对其质构特征、氨基酸组分、脂肪酸组分的变化规律进行分析。结果表明:整个发酵阶段,包含10个门类群、30个纲类群、60个目类群、90个科类群、130个属类群。在发酵初期(0~10 d),细菌群落多样性丰富,相对丰度大于0.1%的科水平达40多个,其优势菌为葡葡萄球菌科(Staphylococcaceae)(48%)、肠球菌科(Enterococcaceae)(9.46%)、餐古菌科(Cenarchaeaceae)(5.57%)、红细菌科(Rhodobacteraceae)(2.12%)。随着发酵时间的延长(10~50 d),芽孢杆菌科(Bacillaceae)相对丰度值由0.017%上升为1.35%,乳杆菌科(Lactobacillaceae)由0.018%上升为0.88%,明串珠菌科(Leuconostocaceae)由0.0%上升为0.61%,链球菌科(Streptococcaceae)由0.002%上升为0.32%,莫拉菌科(Moraxellaceae)由0.006%上升为0.31%;而黄杆菌科(Flavobacteriaceae)、海洋螺菌科(Oceanospirillaceae)、假交替单胞菌科(Pseudoalteromonadaceae)、交替单胞菌科(Alteromonadaceae)等随着发酵时间的延长快速下降,餐古菌科(Cenarchaeaceae)下降为零,其优势菌转变为葡萄球菌、肠球菌和乳酸类细菌。另外,肠杆菌科(Enterobacteriaceae)在发酵50 d后有快速生长的趋势,对发酵有不利影响。同时发现质构指标、氨基酸组分含量、饱和脂肪酸含量随着发酵时间的延长而显下降趋势,并与时间在0.01水平(双侧)上显著负相关。因此,发酵时间控制在一定范围内有利于保证产品质量安全。展开更多
The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium e...The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium extraction with over 90% at the Fe/S ratio of 5:0.5, 5:1 and 5:5, while poor extraction(<46%) at the Fe/S ratio of 5:0 and 5:10.Furthermore, the bacterial community analysis based on species-specific gyrB numbers indicated that, absent sulfur or excessive sulfur would be not conducive to the synergistic growth for A. ferrooxidans and A. thiooxidans, and then not conducive to the uranium dissolution. Meanwhile, the sulfur-oxidizers could play an important role in the process of uranium synergistic bioleaching by mixed bacterial consortia. Additionally, the characteristics of mineral residue was detected by SEM-EDS. The results showed appropriate sulfur dosage would change the structure and improve the porosity of passivation substance. Lastly, the uranium dissolution kinetics and biochemical reaction mechanism was analyzed. It indicated that the biochemical reaction coupling iron and sulfur had a pleiotropic effect on the uranium dissolution from the ore particles, appropriate Fe/S ratio is the key factor for uranium bioleaching by chemoautotrophic acidophiles.展开更多
基金Project(51804165) supported by the National Natural Science Foundation of ChinaProject(2018JJ3441) supported by the Natural Science Foundation of Hunan Province,China。
文摘The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium extraction with over 90% at the Fe/S ratio of 5:0.5, 5:1 and 5:5, while poor extraction(<46%) at the Fe/S ratio of 5:0 and 5:10.Furthermore, the bacterial community analysis based on species-specific gyrB numbers indicated that, absent sulfur or excessive sulfur would be not conducive to the synergistic growth for A. ferrooxidans and A. thiooxidans, and then not conducive to the uranium dissolution. Meanwhile, the sulfur-oxidizers could play an important role in the process of uranium synergistic bioleaching by mixed bacterial consortia. Additionally, the characteristics of mineral residue was detected by SEM-EDS. The results showed appropriate sulfur dosage would change the structure and improve the porosity of passivation substance. Lastly, the uranium dissolution kinetics and biochemical reaction mechanism was analyzed. It indicated that the biochemical reaction coupling iron and sulfur had a pleiotropic effect on the uranium dissolution from the ore particles, appropriate Fe/S ratio is the key factor for uranium bioleaching by chemoautotrophic acidophiles.
