Abstract：
This study evaluated the rheological behavior of the pig waste biotransformation process to produce lactic acid (LA) and biomass with Lactobacillus acidophilus in a stirred reactor. In addition, cell growth, carbohydrate consumption, and LA production were measured at three different agitation speeds, 100, 150, and 200 rpm at 37 °C, with a reaction time of 52 h. During the development of the process, the kinetic and rheological parameters were obtained using the logistic, Gompertz, generalized Gompertz, Ostwald de Waele, and Herschel-Bulkley mathematical models, respectively. The substrate used was pig manure, to which molasses was added at 12% v/v to increase the concentration of carbohydrates. The results suggest that mass exchange is favorable at low agitation speeds. Nevertheless, the presence of molasses rich in carbohydrates as a carbon source modifies the characteristics of the fluid, dilatant (n > 1) at the beginning of the process to end up as pseudoplastic (n < 1) due to the addition of exopolysaccharides and the modification of the physical structure of the substrate. This effect was confirmed by the Herschel-Bulkley model, which presented a better fit to the data obtained, in addition to finding a direct relationship between viscosity and pH that can be used as variables for the control of bioconversion processes of pig manure into biomass rich in Lactobacillus acidophilus.
摘要：
这项研究评估了在搅拌反应器中与嗜酸乳杆菌一起生产乳酸（LA）和生物质的猪废物生物转化过程的流变行为。此外,细胞生长,碳水化合物的消耗，在三种不同的搅拌速度下测量LA的产量，在37°C时100、150和200rpm，反应时间为52小时。在该过程的开发过程中，动力学和流变参数是使用逻辑获得的，Gompertz,广义Gompertz,OstwalddeWaele,和Herschel-Bulkley数学模型,分别。使用的基质是猪粪，以12%v/v加入糖蜜以增加碳水化合物的浓度。结果表明，在低搅拌速度下，质量交换是有利的。然而，富含碳水化合物的糖蜜作为碳源的存在改变了流体的特性，由于添加胞外多糖和底物物理结构的修饰，在过程开始时膨胀（n>1）最终成为假塑性（n<1）。Herschel-Bulkley模型证实了这种效应，这对获得的数据有更好的拟合，除了发现粘度和pH之间的直接关系，可以用作控制猪粪生物转化过程中富含嗜酸乳杆菌的生物质的变量。
