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比较了Acidithiobacillus ferrooxidans对环状硫(α-S)和线状硫(μ-S)的利用差异。A.ferrooxidans在这2种单质硫中生长和硫氧化的结果表明该菌对μ-S的利用与α-S明显不同。尽管生长300 h后该菌在2种单质硫基质中达到相同的细胞浓度、相同的pH和硫酸根离子浓度,但在初始阶段细菌细胞在μ-S中生长时的细胞生长速率、pH下降速率和硫酸根增加速率比在α-S中生长时明显快。A.ferrooxidans对这2种硫的初始吸附行为研究表明该细菌对μ-S的平衡吸附量明显高于α-S。SEM、DRIFTS和XRD结果表明,A.ferrooxidans对这2种单质硫表面进行了不同的修饰。选取了11个与硫吸附活化和代谢相关基因通过RT-qPCR进行差异表达分析,结果显示A.ferrooxidans在μ-S中生长时,与疏水性底物转运蛋白和硫代谢相关蛋白表达量比在α-S中生长时明显上调,而吸附和活化相关蛋白表达下调,表明μ-S比α-S易于被A.ferrooxidans适应和活化。
The differences in the utilization of Cyclic Sulfur (α-S) and Linear Sulfur (μ-S) by Acidithiobacillus ferrooxidans were compared. The results of the growth and sulfur oxidation of A.ferrooxidans in these two kinds of elemental sulfur show that the utilization of μ-S by the bacteria is significantly different from that of α-S. Although this bacterium reached the same cell concentration, the same pH and the sulfate ion concentration in the two elemental sulfur substrates after 300 h of growth, the cell growth rate, the rate of decrease in pH at the initial stage of bacterial cell growth in μ-S And the rate of sulfate increase was significantly faster than when grown in α-S. Studies on the initial adsorption behavior of these two sulfur species by A. ferrooxidans showed that the equilibrium adsorption capacity of μ-S to the bacteria was significantly higher than that of α-S. SEM, DRIFTS and XRD results showed that A.ferrooxidans modified the two elemental sulfur surfaces differently. The differential expression analysis of 11 genes related to activation and metabolism of sulfur adsorption by RT-qPCR was carried out. The results showed that when A. ferrooxidans was grown in μ-S, the expression ratio of hydrophobic substrate transporter and sulfur metabolism related protein was α-S increased significantly, while the expression of protein adsorption and activation down-regulated, indicating that μ-S than α-S easily adapted and activated by A. ferrooxidans.