High production of 1,3-propanediol from industrial glycerol by a newly isolated Clostridium butyricum strain.
Batch and continuous cultures of a newly isolated Clostridium butyricum strain were carried out on industrial glycerol, the major by-product of the bio-diesel production process. For both types of cultures, the conversion yield obtained was around 0.55 g of 1,3-propanediol formed per 1 g of glycerol consumed whereas the highest 1,3-propanediol concentration, achieved during the single-stage continuous cultures was 35-48 g l-1. Moreover, the strain presented a strong tolerance at the inhibitory effect of the 1,3-propanediol, even at high concentrations of this substance at the chemostat (e.g. 80 g l-1). 1,3-Propanediol was associated with cell growth whereas acetate and butyrate seemed non growth-associated products. At low and medium dilution rates (until 0.1 h-1), butyrate production was favoured, whereas at higher rates acetate production increased. The maximum 1,3-propanediol volumetric productivity obtained was 5.5 g l-1 h-1. A two-stage continuous fermentation was also carried out. The first stage presented high 1,3-propanediol volumetric productivity, whereas the second stage (with a lower dilution rate) served to further increase the final product concentration. High 1,3-propanediol concentrations were achieved (41-46 g l-1), with a maximum volumetric productivity of 3.4 g l-1 h-1. A cell concentration decrease was reported between the second and the first fermentor.
Papanikolaou
S
S
Laboratoire des Sciences du Génie Chimique-C.N.R.S.-Ecole Nationale Supérieure des Industries Chimiques-U.P.R. 6811, Vandoeuvre-les-Nancy, France.
Ruiz-Sanchez
P
P
Pariset
B
B
Blanchard
F
F
Fick
M
M
D019149:Bioreactors; D002617:Chemical Industry; D003013:Clostridium / Q000254:growth & development / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D011409:Propylene Glycols / Q000378:metabolism*
D011409:Propylene Glycols; C041787:1,3-propanediol; D005990:Glycerol