title: Bioconversion of glycerol to 1,3-propanediol in thin stillage-based media by engineered Lactobacillus panis PM1.
abstract: 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.
authors: Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
authors: Tae Sun
authors: TS
authors: Kang
authors: Darren R
authors: DR
authors: Korber
authors: Takuji
authors: T
authors: Tanaka
mesh_terms: D000449:Aldehyde Reductase / Q000235:genetics / Q000378:metabolism; D056804:Biofuels; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism*; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D060847:Metabolic Engineering; D011409:Propylene Glycols / Q000378:metabolism*; D014865:Waste Disposal, Fluid; D014866:Waste Products
chemical_list: D056804:Biofuels; D029968:Escherichia coli Proteins; D011409:Propylene Glycols; D014866:Waste Products; C041787:1,3-propanediol; D000449:Aldehyde Reductase; C528732:YqhD protein, E coli; D005990:Glycerol