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Item type:Publication, Access status: without files , Impact of anaerobiosis strategy and bioreactor geometry on the biochemical response of Clostridium butyricum VPI 1718 during 1,3-propanediol fermentation(Elsevier, 2011-09-12); ; ; ; The impact of anaerobiosis strategy on 1,3-propanediol production during cultivation of Clostridium butyricum VPI 1718 in different size bioreactors was studied. In batch trials with N 2 gas infusion, the fermentation was successfully accomplished, regardless of initial glycerol concentration imposed and bioreactor geometry. However, in the absence of N 2 continual sparging, significant variations concerning the biochemical response of the strain were observed. Specifically, at 1-L bioreactor, the absence of N 2 infusion at high initial glycerol concentration induced lactate dehydrogenase activity and thus lactic acid synthesis, probably due to partial blockage of phosphoroclastic reaction caused by insufficient self-generated anaerobiosis environment. During fed-batch cultivation with continual N 2 sparging, the strain produced ∼71gL -1 of 1,3-propanediol, whereas under self-generated anaerobiosis, 1,3-propanediol pathway was evidently restricted, as only 30.5gL -1 of 1,3-propanediol were finally produced. Apparently, N 2 infusion strategy paired with bioreactor geometry can alter the biochemical behavior of the particular strain.Publicationtype: Journal ArticleScopus© Citations 38 14 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Production of 1,3-propanediol by Clostridium butyricum growing on biodiesel-derived crude glycerol through a non-sterilized fermentation process(Springer, 2011-04-12); ; ; ; The aim of the present study was to investigate the production of 1,3-propanediol (PDO) under non-sterile fermentation conditions by employing the strain Clostridium butyricum VPI 1718. A series of batch cultures were performed by utilizing biodiesel-derived crude glycerol feedstocks of different origins as the sole carbon source, in various initial concentrations. The strain presented similarities in terms of PDO production when cultivated on crude glycerol of various origins, with final concentrations ranging between 11.1 and 11.5 g/L. Moreover, PDO fermentation was successfully concluded regardless of the initial crude glycerol concentration imposed (from 20 to 80 g/L), accompanied by sufficient PDO production yields (0.52-0.55 g per gram of glycerol consumed). During fed-batch operation under non-sterile culture conditions, 67.9 g/L of PDO were finally produced, with a yield of 0.55 g/g. Additionally, the sustainability of the bioprocess during a continuous operation was tested; indeed, the system was able to run at steady state for 16 days, during which PDO effluent level was 13.9 g/L. Furthermore, possible existence of a microbial community inside the chemostat was evaluated by operating a polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis, and DGGE results revealed the presence of only one band corresponding to that of C. butyricum VPI 1718. Finally, non-sterile continuous cultures were carried out at different dilution rates (D), with inlet glycerol concentration at 80 g/L. Maximum PDO production was achieved at low D values (0.02 h -1) corresponding to 30.1 g/L, while the elaboration of kinetic data from continuous cultures revealed the stability of the bioprocess proposed, with global PDO production yield corresponding to 0.52 g/g.Publicationtype: Journal ArticleScopus© Citations 147 25