College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen University, Shenzhen, 518060, China.
Guangdong Province Key Laboratory of Durability for Marine Civil Engineering, The Key Laboratory on Durability of Civil Engineering in Shenzhen, School of Civil Engineering, Shenzhen University, Shenzhen, 518060, China.
Appl Microbiol Biotechnol. 2016 Dec;100(24):10295-10306. doi: 10.1007/s00253-016-7741-z. Epub 2016 Jul 26.
A strategy to supply molecular oxygen for microbial calcium precipitation was developed for the first time. Firstly, a controlled oxygen-releasing tablet (ORT) containing CaO and lactic acid with a suitable ratio of 9:1 was developed. It can provide a stable oxygen supply and maintain pH in the range of 9.5-11.0 for 45 days while contacting with water. In the presence of oxygen, a self-healing bacterium H4 spores germinated more effectively and maintained high metabolic activity. Furthermore, H4 vegetative cells induced 50 % more calcium precipitation than that obtained without oxygen supply. Finally, a binary self-healing system containing bacterial spores and ORT was established. The calcium precipitation experiments showed that H4 in the binary self-healing system precipitated 27.5 mM calcium with oxygen supply after 32 days and dissolved oxygen (DO) concentration of the solution decreased from 15 to 4 mg l, while only 6.9 mM calcium precipitation was obtained without oxygen supply. This work can disclose the effect of oxygen on microbial calcium precipitation and further lay a foundation for the establishment of ternary self-healing system containing bacteria, ORT, and nutrients, which will be promising for the self-healing of cracks deep inside the concrete structure.
首次开发了一种为微生物钙沉淀供应分子氧的策略。首先，开发了一种含有 CaO 和乳酸的控释片剂（ORT），其比例为 9:1，与水接触时可以提供稳定的氧气供应，并将 pH 值维持在 9.5-11.0 范围内 45 天。在氧气存在的情况下，自修复细菌 H4 孢子更有效地发芽并保持高代谢活性。此外，H4 营养细胞诱导的钙沉淀比没有供氧时多 50%。最后，建立了包含细菌孢子和 ORT 的二元自修复系统。钙沉淀实验表明，在供氧条件下，二元自修复系统中的 H4 在 32 天后沉淀了 27.5 mM 的钙，溶液中的溶解氧（DO）浓度从 15 降至 4 mg·l，而没有供氧时仅沉淀了 6.9 mM 的钙。这项工作可以揭示氧气对微生物钙沉淀的影响，并进一步为建立包含细菌、ORT 和营养物质的三元自修复系统奠定基础，这对于混凝土结构内部裂缝的自修复具有广阔的前景。
