硫代硫酸钠对排硫硫杆菌固碳能力的影响及其作用机制

Effect of Thiosulfate on the Carbon Fixation Capability of Thiobacillus thioparus and Its Mechanism

通过测定不同浓度Na_2S_2O_3·5H_2O培养时排硫硫杆菌(DSM 505)菌液的总有机碳浓度(TOC),分析Na_2S_2O_3·5H_2O对排硫硫杆菌固碳能力的影响,并结合各浓度Na_2S_2O_3·5H_2O条件下固碳关键酶Rubis CO编码基因cbb的转录特性和胞外游离有机碳浓度(EFOC),阐明Na_2S_2O_3·5H_2O影响排硫硫杆菌固碳能力的作用机制.结果表明,适当范围内增加Na_2S_2O_3·5H_2O的浓度能显著提高排硫硫杆菌的固碳能力,降低胞外游离有机碳在总有机碳中所占的比例.cbb基因转录特性分析结果表明,Na_2S_2O_3·5H_2O浓度对cbb基因的转录效率和表达模式均无显著影响.因此推测Na_2S_2O_3·5H_2O影响排硫硫杆菌固碳能力的作用机制可能是作为电子供体提供能量,促进细胞骨架合成,从而削弱胞外游离有机碳对排硫硫杆菌自养过程的抑制作用,进而增强固碳能力.

The effect of Na2S2O3·5H2O on the carbon fixation capability of Thiobacillus thioparus（DSM 505） was determined by measuring the total organic carbon （TOC） concentrations under different concentrations of Na2S2O3·5H2O. In addition, the mechanism was clarified by analyzing the transcription characteristics of RubisCO-encoding genes （cbb genes） and the concentrations of extracellular free organic carbon （EFOC） under different concentrations of Na2S2O3·5H2O. The result showed that by increasing the concentrations of Na2S2O3·5H2O appropriately, the carbon fixation capability of Thiobacillus thioparus could be promoted and the ratio of extracellular free organic carbon to total organic carbon fell significantly. Moreover, the analysis from the transcription characteristics of cbb genes revealed that Na2S2O3·5H2O had no significant effect on the transcription efficiency and transcription pattern of cbb genes. So Na2S2O3·5H2O might improve the carbon fixation capability by promoting the cytoskeleton synthesis rate as electron donors to eliminate the inhibition effect of extracellular free organic carbon on the carbon fixation of Thiobacillus thioparus.