Effects of carbon anhydrase on utilization of bicarbonate in microalgae:a case study in Lake Hongfeng  

作　　者：Haitao Li Yanyou Wu Lihua Zhao 

机构地区：[1]State Key Laboratory of Environmental Geochemistry/Institute of Geochemistry,Chinese Academy of Sciences [2]School of Karst Science,Guizhou Normal University/State Engineering Technology Institute for Karst Desertfication Control

出　　处：《Acta Geochimica》2018年第4期519-525,共7页地球化学学报（英文）

基　　金：supported by the National Natural Sciences Foundation of China (U1612441);Foundation of Guizhou Province ([2014] 2131);Doctor Foundation of Guizhou Normal University (0514014)

摘　　要：A bidirectional labeling method was established to distinguish the proportions of HCO3- and CO2 utiliza- tion pathways of microalgae in Lake Hongfeng. The method was based on microalgae cultured in a medium by adding equal concentrations of NaH13CO3 with different 613C values simultaneously. The inorganic carbon sources were quantified according to the stable carbon isotope composition in the treated microalgae. The effects of extracellular carbonic anhydrase （CAex） on the HCO3 and CO2 utilization pathways were distinguished using acetazolamide, a potent membrane-impermeable carbonic anhydrase inhibitor. The results show utilization of the added HCO3- was only 8% of the total carbon sources in karst lake. The proportion of the HCO3- utilization path- way was 52% of total inorganic carbon assimilation. Therefore, in the natural water of the karst area, the microalgae used less bicarbonate that preexisted in the aqueous medium than CO2 derived from the atmosphere. CAex increased the utilization of inorganic carbon from the atmosphere. The microalgae with CAex had greater carbon sequestration capacity in this karst area.A bidirectional labeling method was established to distinguish the proportions of HCO_3^- and CO_2 utilization pathways of microalgae in Lake Hongfeng. The method was based on microalgae cultured in a medium by adding equal concentrations of NaH^(13)CO_3 with different δ^(13)C values simultaneously. The inorganic carbon sources were quantified according to the stable carbon isotope composition in the treated microalgae. The effects of extracellular carbonic anhydrase(CAex) on the HCO^-_3 and CO_2 utilization pathways were distinguished using acetazolamide, a potent membrane-impermeable carbonic anhydrase inhibitor. The results show utilization of the added HCO^-_3 was only 8% of the total carbon sources in karst lake. The proportion of the HCO^-_3 utilization pathway was 52% of total inorganic carbon assimilation. Therefore, in the natural water of the karst area, the microalgae used less bicarbonate that preexisted in the aqueous medium than CO_2 derived from the atmosphere. CAex increased the utilization of inorganic carbon from the atmosphere. The microalgae with CAex had greater carbon sequestration capacity in this karst area.

关 键 词：MICROALGAE Carbonic anhydrase Stable carbon isotope Inorganic carbon utilization 

分 类 号：P342[天文地球—水文科学]