针对传统微生物诱导碳酸钙沉淀（microbially induced calcium carbonate precipitation，简称MICP）技术依赖外源菌种、成本高昂及黄土适用性差等问题，本研究在胶结液中引入环保型木质素磺酸钙代替传统钙源，通过单因素与响应面Box- Behnken设计试验优化营养物质酵母提取物（yeastextract，简称YE）、NH4Cl、尿素与钙源浓度，靶向激活土著产脲酶微生物固化黄土，结合生物活性监测、无侧限抗压强度试验、碳酸钙生成量测定、扫描电镜（scanning electron microscope，简称SEM）、X射线衍射（X-ray diffraction，简称XRD）及高通量测序技术，系统揭示固化机制。结果表明：优化后的营养物质浓度为YE浓度1.2 g/L、NH4Cl浓度125 mmol/L、尿素与钙源浓度0.8 mol/L；优化组的脲酶活性、pH值和活菌数在反应120 h时达到峰值，显著促进了碳酸钙的沉积；优化组的无侧限抗压强度、割线模量和碳酸钙含量较空白组（素黄土）分别提高了131.42%、194.32%和734.65%；反应生成的针状/棒状碳酸钙晶体通过填充-桥接-胶结作用显著提升了土体的强度和密实度；优化组中芽孢杆菌目（Bacillales）相对丰度达到93%，土体中微生物群落的丰富程度和组成结构发生了改变。研究结果可为靶向激活技术在黄土地区的工程应用提供参考。To address the limitations of traditional microbiallyinduced calcium carbonate precipitation (MICP) technology

including relianceon exogenous bacterial strains

high costs

and poor applicability tofine-grained loess

this study introduces environmentally friendly calciumlignosulfonate into the cement solution instead of the traditional calciumsource

and optimizes concentrations of nutrient yeast extract (YE)

NH4Cl

urea-calcium source through single-factor and response surface Box-Behnkendesign experiments. By targeting the activation of indigenous urease-producingmicroorganisms for loess solidification

we systematically investigate thesolidification mechanisms using bioactivity monitoring

unconfined compressivestrength tests

calcium carbonate quantification

scanning electron microscope (SEM)

X-ray diffraction (XRD) and high-throughput sequencing. The results show that:the optimized nutrient concentrations are 1.2 g/L for YE

125 mmol/L for NH4Cland 0.8 mol/L for urea-calcium source; the urease activity

pH value

and viablebacterial count in the optimized group peak at 120 hours of reaction

significantly promoting calcium carbonate deposition; compared to the controlgroup (untreated loess)

the optimized group exhibits 131.42%

194.32%

and734.65% improvements in unconfined compressive strength

secant modulus

andcalcium carbonate content

respectively; needle/rod-shaped calcium carbonatecrystals formed during the reaction significantly enhance soil strength andcompactness through filling-bridging-cementation effects; the relativeabundance of Bacillales in the optimized group reaches 93%

with notablechanges in microbial community diversity and composition. These findingsprovide a reference for the engineering application of targeted activationtechnology in loess regions.