In this publication an alternative approach to investigations of bacterial growth is proposed. Contrary to the conventional physical methods it is based on enzyme activity detection. The procedure for real-time and on-line monitoring of microbial ureolytic activity (applied as a model experimental biosystem) in the flow analysis format is presented. The developed fully-mechanized bioanalytical flow system is composed of solenoid micropumps and microvalves actuated by Arduino microcontroller. The photometric detection based on Nessler reaction is performed using dedicated flow-through optoelectronic detector made of paired light emitting diodes. The developed bioanalytical system allows discrete assaying of microbial urease in the wide range of activity up to 5.4 U mL⁻¹ with detection limit below 0.44 U mL⁻¹, a high sensitivity in the linear range of response (up to 200 mV U⁻¹ mL and relatively high throughput (9 detection per hour). The proposed differential procedure of measurements (i.e. a difference between peaks register for sample with and without external addition of urea is treated as an analytical signal) allows elimination of interfering effects from substrate and products of biocatalysed reaction as well as other components of medium used for microbial growth. The developed bioanalytical system was successfully applied for the control of growth of urease-positive bacteria strains (Proteus vulgaris, Klebsiella pneumoniae and Paracoccus yeei) including examination of effects from various microbial cultivation conditions like temperature, composition of culture medium and amount of substrate required for induction of bacterial enzymatic activity. The developed bioanalytical flow system can be applied for metabolic activity-based estimation of parameters of lag and log phases of microbial growth as well as for detection of decline phase.

在本出版物中，提出了一种研究细菌生长的替代方法。与传统的物理方法相反，它基于酶活性检测。介绍了在流动分析格式中实时和在线监测微生物尿素分解活性（用作模型实验生物系统）的过程。开发的全机械化生物分析流动系统由由 Arduino 微控制器驱动的螺线管微型泵和微型阀组成。基于奈斯勒反应的光度检测是使用由成对发光二极管制成的专用流通光电检测器进行的。开发的生物分析系统允许在高达 5.4 U mL ^-1的广泛活性范围内对微生物脲酶进行离散测定，检测限低于 0.44 U mL^-1，响应线性范围内的高灵敏度（高达 200 mV U ^-1 mL 和相对较高的吞吐量（每小时 9 次检测）。建议的测量差分程序（即，有和没有样品的峰值记录之间的差异）尿素的外部添加被视为分析信号）可以消除来自底物和生物催化反应产物以及用于微生物生长的培养基的其他成分的干扰作用。开发的生物分析系统已成功应用于控制尿素酶的生长-阳性菌株（变形杆菌、肺炎克雷伯菌和伊氏副球菌）) 包括检查各种微生物培养条件的影响，如温度、培养基组成和诱导细菌酶活性所需的底物量。开发的生物分析流系统可用于基于代谢活动的微生物生长滞后期和对数期参数的估计，以及衰退期的检测。