Highly efficient fermentation of glycerol and 1,3-propanediol using a novel starch as feedstock

As a potential cost-effective feedstock for highly efficient fermentation of glycerol and its downstream product 1,3-propanediol(1,3-PD),duckweed starch was characterized and used for glycerol fermentation,for the first time,in this study.Genes involved in glycerol biosynthesis(gpd1 and gpp2)were overexpressed in Escherichia coli,and genes involved in glycerol catabolism(glpK and gldA)were disrupted,which led to significantly decreased residual sugar levels and dramatically increased glycerol production.The maximum glycerol concentration in fed-batch fermentation reached 102.72 g L^(-1) at 28 h,and the glycerol productivity was 3.67 g L^(-1) h^(-1),which,to our knowledge,is the highest productivity thus far reported.Subsequently,glycerol broth was fermented into 1,3-PD by Klebsiella pneumoniae.The concentration,conversion rate and productivity of 1,3-PD reached 35.54 g L^(-1),40.28%and 0.89 g L^(-1) h^(-1),respectively,without optimization.In summary,the duckweed starch-to-glycerol-to-1,3-PD process is feasible and shows potential for improving glycerol industry competitiveness.

微生物发酵法生产1,3-丙二醇研究进展

综述了世界上微生物发酵法生产1,3-丙二醇(PDO)的发酵菌种、发酵工艺、基因工程产物的提取的研究进展,并介绍清华大学化工系在发酵法生产甘油专利技术的基础上,进一步开发了二步发酵由葡萄糖生产PDO的新工艺,并将电渗析脱盐技术引入了PDO的后提取工艺中。通过5000L发酵罐的中试实验表明,发酵液中PDO平均浓度可达62g/L,PDO对甘油摩尔得率0.6,后提取收率80%。