Hou Yuyong, Liu Zhiyong, Zhao Yue, Chen Shulin, Zheng Yubin, Chen Fangjian
Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China.
Shandong Jinjing Biotechnology Co., Ltd., Shandong 261313, PR China.
Enzyme Microb Technol. 2016 Jun;87-88:17-23. doi: 10.1016/j.enzmictec.2016.02.010. Epub 2016 Feb 23.
Outdoor microalgal cultivation with high concentration bicarbonate has been considered as a strategy for reducing contamination and improving carbon supply efficiency. The mechanism responsible for algae's strong tolerance to high bicarbonate however, remains not clear. In this study, we isolated and characterized a strain and revealed its high bicarbonate tolerant mechanism by analyzing carbonic anhydrase (CA). The strain was identified as Dunaliella salina HTBS with broad temperature adaptability (7-30°C). The strain grew well under 30% CO2 or 70gL(-1) NaHCO3. In comparison, two periplasm CAs (CAH1 and CAH2) were detected with immunoblotting analysis in HTBS but not in a non-HCO3(-)-tolerant strain. The finding was also verified by an enzyme inhibition assay in which only HTBS showed significant inhibition by extracellular CA inhibitor. Thus, we inferred that the extracellular CAH1 and CAH2 played a multifunctional role in the toleration of high bicarbonate by HTBS.
利用高浓度碳酸氢盐进行室外微藻培养被认为是一种减少污染和提高碳供应效率的策略。然而，藻类对高浓度碳酸氢盐具有强耐受性的机制仍不清楚。在本研究中，我们分离并鉴定了一个菌株，并通过分析碳酸酐酶（CA）揭示了其对高浓度碳酸氢盐的耐受机制。该菌株被鉴定为具有广泛温度适应性（7-30°C）的杜氏盐藻HTBS。该菌株在30% CO2或70gL(-1) NaHCO3条件下生长良好。相比之下，通过免疫印迹分析在HTBS中检测到两种周质CA（CAH1和CAH2），而在不耐受HCO3(-)的菌株中未检测到。这一发现也通过酶抑制试验得到验证，在该试验中，只有HTBS受到细胞外CA抑制剂的显著抑制。因此，我们推断细胞外CAH1和CAH2在HTBS对高浓度碳酸氢盐的耐受性中发挥了多功能作用。
