Converting crude glycerol to 1,3-propandiol using resting and immobilized Klebsiella sp. HE-2 cells

In this study, 1,3-propanediol (1,3-PDO) was produced from crude glycerol through the fermentation of resting and immobilized cells of a Klebsieblla sp. HE-2 strain isolated from a hydrogen producing anaerobic sludge collected in Southern Taiwan. The Klebsieblla sp. HE-2 cells were first grown on a fermentation medium (FM medium). The medium was then switched to resting-cell medium (RC medium) tailored to improve the production of 1,3-PDO. Using a glycerol-amended FM medium, the soluble metabolites consisted of 1,3-PDO, 2,3-butanediol, and ethanol and byproducts (such as acetic acid and lactic acid) at a content of 18, 28, 49, and 5% (of total soluble metabolites), respectively. When the culture was transferred from the FM medium to the RC medium, the concentration of 1,3-PDO was doubled from 5 g/L to 10 g/L. Using immobilized cells of Klebsieblla sp. HE-2 greatly improved the operational stability and reusability of the cells, as the immobilized cells could be used for 6 cycles without significant activity loss. The immobilized cells were able to directly utilize non-pretreated crude glycerol obtained from a local biodiesel manufacturing plant for 1,3-PDO production with an efficiency comparable to that obtained from using pure glycerol.

► Efficient 1,3-PDO fermentation technology was developed with indigenous Klebsieblla sp. ► Resting-cell operation with optimal medium and culture conditions enhanced 1,3-PDO production. ► Using immobilized cells greatly improved the operational stability and reusability. ► Crude glycerol from biodiesel manufacture plant could be converted to 1,3-PDO efficiently.