Department of Chemical Engineering/School of Engineering, USC, University of Santiago de Compostela, Rúa Lope Gómez de Marzoa s/n, 15782, Santiago de Compostela, Spain.
Bioprocess Biosyst Eng. 2011 Sep;34(7):869-78. doi: 10.1007/s00449-011-0537-8. Epub 2011 Apr 2.
A mathematical model describing the kinetics of the sequential production of lactic acid and xylitol from detoxified-concentrated vine trimming hemicellulosic hydrolysates by Lactobacillus rhamnosus and Debaryomyces hansenii, respectively, was developed from the basic principles of mass balance in two stages considering as main reactions: (1) glucose and xylose consumption by L. rhamnosus; and (2) xylitol and arabitol production by D. hansenii. The model allows to evaluate the yields and productivities under microaerobic and oxygen restricted conditions (in particular the effects caused by purging the oxygen with nitrogen), which were particularly important during the xylose to xylitol bioconversion by yeasts. The model was tested using experimental data obtained from detoxified-concentrated hemicellulosic hydrolysates, after CaCO3 addition in both types of fermentation processes, without purges (microaerobic conditions) or purging oxygen with nitrogen (oxygen-limited conditions) after sampling in order to reduce the oxygen dissolved. L. rhamnosus was removed by microfiltration before adding D. hansenii at the beginning of the second stage. Mass balance-based and logistic functions were successfully applied to develop the model of the system which properly predicts the consumption of sugars as well as the metabolites produced and yields. The dynamics of fermentation were also adequately described by the developed model.
从质量平衡的基本原理出发，针对两个阶段的主要反应，分别建立了描述鼠李糖乳杆菌和汉逊德巴利酵母分别从解毒浓缩葡萄修剪半纤维素水解物顺序生产乳酸和木糖醇的动力学的数学模型：（1）L. rhamnosus 消耗葡萄糖和木糖；（2）D. hansenii 生产木糖醇和阿拉伯糖醇。该模型可评估微需氧和缺氧条件下（特别是在通过氮气吹扫去除氧气时）的产率和生产力，这在酵母进行木糖到木糖醇生物转化过程中尤为重要。该模型使用从解毒浓缩半纤维素水解物获得的实验数据进行了测试，在两种发酵过程中均添加 CaCO3 后，不进行吹扫（微需氧条件）或用氮气吹扫去除氧气（缺氧条件），以便在取样后降低溶解氧。在添加汉逊德巴利酵母之前，通过微滤去除鼠李糖乳杆菌。基于质量平衡和逻辑函数的模型成功地开发了该系统的模型，该模型可以很好地预测糖的消耗以及产生的代谢物和产率。所开发的模型还可以很好地描述发酵动力学。
