Bio-concrete using bacterially produced calcium carbonate can repair microcracks but is still relatively expensive due to the addition of bacteria, nutrients, and calcium sources. Agricultural by-products and oyster shells were used to produce economical bio-concrete. Sesame meal was the optimal agricultural by-product for low-cost spore production of the alkaliphilic Bacillus miscanthi strain AK13. Transcriptomic dataset was utilized to compare the gene expressions of AK13 strain under neutral and alkaline conditions, which suggested that NaCl and riboflavin could be chosen as growth-promoting factors at alkaline pH. The optimal levels of sesame meal, NaCl, and riboflavin were induced with the central composite design to create an economical medium, in which AK13 strain formed more spores with less price than in commercial sporulation medium. Calcium nitrate obtained from nitric acid treatment of oyster shell powder increased the initial compressive strength of cement mortar. Non-ureolytic calcium carbonate precipitation by AK13 using oyster shell-derived calcium ions was verified by energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. Stereomicroscope and field emission scanning electron microscopy confirmed that oyster shell-derived calcium ions, along with soybean meal-solution, increased the bacterial survival and calcium carbonate precipitation inside mortar cracks. These data suggest the possibility of commercializing bacterial self-healing concrete with economical substitutes for culture medium, growth nutrient, and calcium sources.

使用细菌产生的碳酸钙进行生物混凝土可以修复微裂纹，但由于添加了细菌，营养素和钙源，其仍然相对昂贵。农业副产品和牡蛎壳被用于生产经济的生物混凝土。芝麻粉是低成本生产嗜碱芽孢杆菌芽孢的最佳农业副产品菌株AK13。利用转录组学数据比较了AK13菌株在中性和碱性条件下的基因表达，提示在碱性pH条件下可以选择NaCl和核黄素作为促生长因子。中央复合设计诱导了芝麻粉，NaCl和核黄素的最佳水平，从而创造了一种经济的培养基，其中AK13菌株比商业孢子形成培养基以更低的价格形成了更多的孢子。硝酸处理的牡蛎壳粉制得的硝酸钙增加了水泥砂浆的初始抗压强度。通过能量色散X射线光谱和X射线衍射分析，证实了使用牡蛎壳来源的钙离子通过AK13沉淀出的非脲溶性碳酸钙。立体显微镜和场发射扫描电子显微镜证实，牡蛎壳来源的钙离子以及豆粕溶液增加了砂浆裂缝内部的细菌存活率和碳酸钙沉淀。这些数据表明，用经济替代培养基，生长营养素和钙源的细菌自修复混凝土进行商业化的可能性。