Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
Appl Microbiol Biotechnol. 2010 Apr;86(3):853-61. doi: 10.1007/s00253-009-2332-x. Epub 2009 Nov 20.
Pullulan is a linear homopolysaccharide which is composed of glucose units and often described as alpha-1, 6-linked maltotriose. The applications of pullulan range from usage as blood plasma substitutes to environmental pollution control agents. In this study, a biofilm reactor with plastic composite support (PCS) was evaluated for pullulan production using Aureobasidium pullulans. In test tube fermentations, PCS with soybean hulls, defatted soy bean flour, yeast extract, dried bovine red blood cells, and mineral salts was selected for biofilm reactor fermentation (due to its high nitrogen content, moderate nitrogen leaching rate, and high biomass attachment). Three pH profiles were later applied to evaluate their effects on pullulan production in a PCS biofilm reactor. The results demonstrated that when a constant pH at 5.0 was applied, the time course of pullulan production was advanced and the concentration of pullulan reached 32.9 g/L after 7-day cultivation, which is 1.8-fold higher than its respective suspension culture. The quality analysis demonstrated that the purity of produced pullulan was 95.8% and its viscosity was 2.4 centipoise. Fourier transform infrared spectroscopy spectra also supported the supposition that the produced exopolysaccharide was mostly pullulan. Overall, this study demonstrated that a biofilm reactor can be successfully implemented to enhance pullulan production and maintain its high purity.
普鲁兰是一种线性同多糖，由葡萄糖单元组成，通常描述为α-1,6-连接的麦芽三糖。普鲁兰的应用范围从作为血浆代用品到环境污染控制剂。在这项研究中，使用出芽短梗霉评估了带有塑料复合载体（PCS）的生物膜反应器在生产普鲁兰中的应用。在试管发酵中，选择了含有大豆皮、脱脂豆粉、酵母提取物、干牛红细胞和无机盐的 PCS 用于生物膜反应器发酵（由于其高氮含量、适中的氮浸出率和高生物量附着）。后来应用了三种 pH 曲线来评估它们对 PCS 生物膜反应器中普鲁兰生产的影响。结果表明，当应用 5.0 的恒 pH 值时，普鲁兰生产的时间进程提前，经过 7 天培养后，普鲁兰的浓度达到 32.9 g/L，是其悬浮培养的 1.8 倍。质量分析表明，所生产的普鲁兰的纯度为 95.8%，其粘度为 2.4 厘泊。傅里叶变换红外光谱谱图也支持了所产生的胞外多糖主要是普鲁兰的假设。总的来说，这项研究表明，生物膜反应器可以成功地用于提高普鲁兰的产量并保持其高纯度。
