Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
J Ind Microbiol Biotechnol. 2014 Apr;41(4):629-35. doi: 10.1007/s10295-014-1403-x. Epub 2014 Feb 13.
Thin stillage (TS) is a waste residue that remains after bioethanol production, and its disposal reflects the high costs of bioethanol production. Thus, the development of cost-effective ways to process TS is a pending issue in bioethanol plants. The aim of this study was to evaluate the utilization of TS for the production of the valuable chemical, 1,3-propanediol (1,3-PDO), by Lactobacillus panis PM1. Different fermentation parameters, including temperature, pH and strains [wild-type and a recombinant strain expressing a NADPH-dependent aldehyde reductase (YqhD) gene] were tested in batch and fed-batch cultivations. The highest 1,3-PDO concentration (12.85 g/L) and yield (0.84 g/g) were achieved by batch fermentation at pH-4.5/30 °C by the YqhD recombinant strain. Furthermore, pH-controlled batch fermentation reduced the total fermentation period, resulting in the maximal 1,3-PDO concentration of 16.23 g/L and yield of 0.72 g/g in TS without an expensive nutrient or nitrogen (e.g., yeast extract, beef extract, and peptone) supplementation. The addition of two trace elements, Mg(2+) and Mn(2+), in TS increased 1,3-PDO yield (0.74 g/g) without 3-hydroxypropionaldehyde production, the only intermediate of 1,3-PDO biosynthetic pathway in L. panis PM1. Our results suggest that L. panis PM1 can offer a cost-effective process that utilizes the TS to produce a value-added chemical, 1,3-PDO.
稀酒糟（TS）是生物乙醇生产后剩余的废渣，其处理反映了生物乙醇生产的高成本。因此，开发经济高效的 TS 处理方法是生物乙醇厂亟待解决的问题。本研究旨在评估利用 TS 通过异常威克汉姆酵母 PM1 生产有价值的化学品 1,3-丙二醇（1,3-PDO）。在分批和补料分批培养中测试了不同的发酵参数，包括温度、pH 值和菌株（野生型和表达 NADPH 依赖型醛还原酶（YqhD）基因的重组菌株）。在 pH-4.5/30°C 下，通过 YqhD 重组菌株进行分批发酵，可获得最高的 1,3-PDO 浓度（12.85 g/L）和产率（0.84 g/g）。此外，pH 控制的分批发酵缩短了总发酵周期，使 TS 中 1,3-PDO 的最大浓度达到 16.23 g/L，产率达到 0.72 g/g，无需昂贵的营养物或氮源（如酵母提取物、牛肉提取物和蛋白胨）补充。在 TS 中添加两种痕量元素 Mg(2+)和 Mn(2+)可提高 1,3-PDO 的产率（0.74 g/g），而不会产生 1,3-PDO 生物合成途径中的唯一中间产物 3-羟基丙醛。我们的结果表明，异常威克汉姆酵母 PM1 可以提供一种经济高效的工艺，利用 TS 生产有附加值的化学品 1,3-PDO。
