【摘要】 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。更多还原

【Abstract】 The differential utilization of cyclic, orthorhombic α-sulfur(α-S) and chain-like polymeric μ-sulfur(μ-S) by Acidithiobacillus ferrooxidans was investigated. The growth and sulfur oxidation results indicated that utilization of μ-S by A. ferrooxidans was clearly different from α-S. Even if the planktonic cells were produced, the fall of pH and the rise of sulfate concentration were the same after 300 h on each substrate, the speeds of the planktonic cells increase, pH decrease and sulfate concentration increase in the earlier cultivation stage were faster on polymeric sulfur compared with the orthorhombic form. The adsorption capacity of the cells was higher on μ-S than on α-S. The results of SEM, DRIFTS and XRD analyses indicated that the surfaces of α-S and μ-S were modified differently by cells. Differential expression of 11 selected sulfur adsorption-activation and metabolism relevant genes was detected by RT-qPCR. The results showed that the expression of the hydrophobic substrate transport proteins and the sulfur metabolism related proteins was up-regulated, and the adsorption and activation related proteins were down-regulated when the cells were grown on μ-S, suggesting that μ-S could be more easily bio-adapted and activated than α-S.更多还原