Chaparro Sandra, Rojas Hugo A, Caicedo Gerardo, Romanelli Gustavo, Pineda Antonio, Luque Rafael, Martínez José J
School of Chemical Sciences, Faculty of Sciences, Pedagogical and Technological University of Colombia, 150001 Tunja, Colombia.
Research and Development Centre on Applied Sciences "Dr. Jorge Ronco" (CCT-La Plata-CONICET, CIC-PBA), National University of La Plata, 1900 La Plata, Argentina.
Materials (Basel). 2021 May 11;14(10):2470. doi: 10.3390/ma14102470.
Whey in large quantities can cause environmental problems when discarded, because it reduces dissolved oxygen and aquatic life. Nonetheless, it could be used as an easily available and economical alternative to reduce culture medium costs in microbially induced calcium carbonate precipitation (MICP). In this work, a native was isolated and then cultured by using different proportions of whey (W) in nutrient broth (NB). The solids were characterized by XRD, FT-IR, TGA, and SEM. The potential applications in bioconsolidation were also studied. Whey concentration was directly related to CaCO production. Higher whey concentrations reduced calcium carbonate purity to nearly 80%. All experiments showed calcite and vaterite fractions, where a whey increment in the media increased calcite content and decreased vaterite content, causing a decrease in crystal size. MICP improved compressive strength (CS) in sand and fly ash. The best CS results were obtained by fly ash treated with 25 W-75 NB (37.2 kPa) and sand with 75 W-25 NB (32.1 kPa). Whey changed crystal polymorphism in biogenic CaCO production. Material bioconsolidation depends on the CaCO polymorph, thus fly ash was effectively bioconsolidated by crystallization of vaterite and sand by crystallization of calcite.
大量乳清被丢弃时会引发环境问题，因为它会降低溶解氧并影响水生生物。尽管如此，在微生物诱导碳酸钙沉淀（MICP）过程中，乳清可作为一种容易获取且经济的替代品，用于降低培养基成本。在本研究中，分离出一种天然菌株，然后在营养肉汤（NB）中使用不同比例的乳清（W）进行培养。通过X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）、热重分析（TGA）和扫描电子显微镜（SEM）对固体进行表征。还研究了其在生物固结方面的潜在应用。乳清浓度与碳酸钙产量直接相关。较高的乳清浓度会使碳酸钙纯度降至近80%。所有实验均显示有方解石和球霰石组分，培养基中乳清含量增加会使方解石含量增加、球霰石含量减少，导致晶体尺寸减小。MICP提高了沙子和粉煤灰的抗压强度（CS）。用25W-75NB处理的粉煤灰（37.2kPa）和75W-25NB处理的沙子（32.1kPa）获得了最佳CS结果。在生物成因碳酸钙生产中，乳清改变了晶体多晶型。材料的生物固结取决于碳酸钙多晶型，因此球霰石结晶有效地固结了粉煤灰，方解石结晶固结了沙子。
