Center for Biofilm Engineering, Montana State University, Bozeman, Montana 59717, USA.
Environ Sci Technol. 2010 Jul 1;44(13):5270-6. doi: 10.1021/es903270w.
The potential of microorganisms for enhancing carbon capture and storage (CCS) via mineral-trapping (where dissolved CO(2) is precipitated in carbonate minerals) and solubility trapping (as dissolved carbonate species in solution) was investigated. The bacterial hydrolysis of urea (ureolysis) was investigated in microcosms including synthetic brine (SB) mimicking a prospective deep subsurface CCS site with variable headspace pressures [p(CO(2))] of (13)C-CO(2). Dissolved Ca(2+) in the SB was completely precipitated as calcite during microbially induced hydrolysis of 5-20 g L(-1) urea. The incorporation of carbonate ions from (13)C-CO(2) ((13)C-CO(3)(2-)) into calcite increased with increasing p((13)CO(2)) and increasing urea concentrations: from 8.3% of total carbon in CaCO(3) at 1 g L(-1) to 31% at 5 g L(-1), and 37% at 20 g L(-1). This demonstrated that ureolysis was effective at precipitating initially gaseous [CO(2)(g)] originating from the headspace over the brine. Modeling the change in brine chemistry and carbonate precipitation after equilibration with the initial p(CO(2)) demonstrated that no net precipitation of CO(2)(g) via mineral-trapping occurred, since urea hydrolysis results in the production of dissolved inorganic carbon. However, the pH increase induced by bacterial ureolysis generated a net flux of CO(2)(g) into the brine. This reduced the headspace concentration of CO(2) by up to 32 mM per 100 mM urea hydrolyzed because the capacity of the brine for carbonate ions was increased, thus enhancing the solubility-trapping capacity of the brine. Together with the previously demonstrated permeability reduction of rock cores at high pressure by microbial biofilms and resilience of biofilms to supercritical CO(2), this suggests that engineered biomineralizing biofilms may enhance CCS via solubility-trapping, mineral formation, and CO(2)(g) leakage reduction.
研究了微生物通过矿物固定（将溶解的 CO₂沉淀在碳酸盐矿物中）和溶解度固定（溶解的碳酸盐物种在溶液中）增强碳捕获和储存（CCS）的潜力。在包括模拟潜在深部地下 CCS 场所的合成盐水（SB）的微环境中研究了尿素的细菌水解（脲水解），该场所具有可变的顶空压力 [p（CO₂）]（¹³C-CO₂）。在微生物诱导的 5-20 g L（-¹）尿素水解过程中，SB 中的溶解 Ca²+完全沉淀为方解石。¹³C-CO₂中的碳酸根离子（¹³C-CO₃（²-））与方解石结合的量随顶空 p（¹³CO₂）和尿素浓度的增加而增加：从 1 g L（-¹）时 CaCO₃中总碳的 8.3%增加到 5 g L（-¹）时的 31%，20 g L（-¹）时为 37%。这表明脲水解有效地沉淀了来自盐水上方顶空的最初气态[CO₂（g）]。通过与初始 p（CO₂）平衡后的盐水化学和碳酸盐沉淀变化的建模表明，没有通过矿物固定发生 CO₂（g）的净沉淀，因为尿素水解导致溶解无机碳的产生。然而，细菌脲水解引起的 pH 值增加导致 CO₂（g）以净通量形式进入盐水。这通过增加盐水的碳酸根离子容量来降低顶空 CO₂浓度，从而增强了盐水的溶解度固定能力。与先前证明的微生物生物膜在高压下降低岩心渗透率以及生物膜对超临界 CO₂的弹性相结合，这表明工程生物矿化生物膜可能通过溶解度固定、矿物形成和 CO₂（g）泄漏减少来增强 CCS。
