(中南大學 資源加工與生物工程學院 生物冶金教育部重點實驗室，長沙 410083)
摘 要: 本研究目的為考察在酵母粉或Cu2+脅迫下，古菌Ferroplasma thermophilum在分別與其他兩種中度嗜熱細菌(Leptospirillum ferriphilum和Acidithiobacillus caldus)混合培養(yǎng)體系中的生態(tài)功能。實驗在250 mL搖瓶中進行，采用純培養(yǎng)與混合培養(yǎng)對照的方法，結合熒光定量PCR(Quantitive PCR, Q-PCR)技術考察F. thermophilum分別與其他兩種中度嗜熱菌之間的協(xié)同作用。結果表明：在0.04%(w/v)酵母粉脅迫下，L. ferriphilum YSK純培養(yǎng)物的生長受到完全抑制，而At. caldus s2純培養(yǎng)物的生長不受抑制。F. thermophilum L1與L. ferriphilum YSK混合培養(yǎng)減輕了酵母粉對L. ferriphilum YSK的抑制作用且促進其生長；F. thermophilum L1/At. caldus s2混合培養(yǎng)體系中，F(xiàn). thermophilum L1的加入能夠促進平穩(wěn)期At. caldus s2的生長。在5 g/L Cu2+脅迫下，F(xiàn). thermophilum L1與 L. ferriphilum YSK混合培養(yǎng)時，F(xiàn). thermophilum L1生長被促進，而L. ferriphilum YSK的生長受到抑制； F. thermophilum L1與At. caldus s2混合培養(yǎng)能夠有效地促進彼此生長，且協(xié)同促進鐵/硫氧化代謝。
關鍵字: 中度嗜熱菌；Ferroplasma thermophilum；協(xié)同作用；酵母粉；Cu2+
（Key Laboratory of Biometallurgy, Ministry of Education,
School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:The purpose of this study was to explore the ecological functions of Ferroplasma thermophilum when it was mixed with Leptospirillum ferriphilum or Acidithiobacillus caldus under the stress of yeast extract or Cu2+. Population dynamics of pure culture and mixed culture were compared by using Quantitative PCR, and synergies between Ferroplasma thermophilum and the other two moderately thermophilic bacteria were evaluated. The results show that the growth of pure L. ferriphilum YSK is inhibited under the stress of 0.04% (w/v) yeast extract. Yet, L. ferriphilum YSK grows well in the presence of F. thermophilum L1, which indicates that the toxicity of yeast extract to L. ferriphilum YSK is reduced in the mixed culture. The results also show that there is no influence of yeast extract on the growth of At. caldus s2 in the pure culture, and compared with the pure culture, the cell density of At. caldus s2 at the stationary phase increases in the mixed culture. Under the stress of 5 g/L Cu2+, when F. thermophilum L1 and L. ferriphilum YSK are mix-cultured, the growth of F. thermophilum L1 can be promoted, while the growth of L. ferriphilum YSK is inhibited. The mixed culture of F. thermophilum and At. caldus has a positive effect on the growth of each other, and can mutually promote ferrous or sulfur oxidation under the stress of 5 g/L Cu2+.
Key words: moderately thermophilic bacteria; Ferroplasma thermophilum; synergy; yeast extract; Cu2+
