Effect of cell immobilization on the production of 1,3-propanediol

Immobilized cultures of locally isolated Klebsiella pneumoniae (GenBank no: 27F HM063413) were employed in the continuous production of the high value added biomonomer, 1,3-propanediol from waste glycerol. The effect of hydraulic retention time (HRT) was tested by increasing the dilution rate gradually. Three different immobilization materials (stainless steel wire, glass raschig ring and Vukopor (R)) were tested. The highest productivity was reported with the reactor filled with stainless steel wire as 4.8 g/(L hours) and the highest 1,3-propanediol concentration was 17.9 g/L when glass raschig rings were used as the packing material with the HRTs of 0.5 hours and 1.5 hours, respectively. Compared to the suspended culture system 1,3-propanediol production was more resistant to shorter hydraulic retention times that leads to higher 1,3-PDO productivities. All three of the materials are good candidates for immobilization purpose; however, stainless steel wire and Vukopor (R) are better support materials in terms of productivities. The results reported in this study revealed that continuous fermentation in a packed-bed bioreactor system is a suitable method to enhance 1,3-propanediol production.