การผลิตสาร 1,3-โพรเพนไดออลจากกลีเซอรอลจากกระบวนการผลิตไบโอดีเซลโดย Clostridium butyricum DSM 5431 และการลดค่าใช้จ่ายในการผลิต โดยการปรับองค์ประกอบของอาหารเลี้ยงเชื้อ / จิรวรรณ แก้วรัตน์ = Production of 1,3-propanediol from biodiesel-based glycerol by clostridium butyricum DSM 5431 and reduction of production expense by modifying the composition of culture medium / Chirawan kaewrat
1,3-propanediol (PD) is a highly valued chemical, which is commonly used as a monomer for biodegradable plastics as well as in other industrial applications. PD production can be accomplished by glycerol fermentation with various bacteria strains under anaerobic condition. Therefore, this research aimed to study the improvement of PD production process and examined the feasibility of reducing the expense associated with the production. In the first part, the research examined the PD production by C. butyricum DSM 5431 with BCN-009 as cell carriers using pure and biodiesel based glycerol as the sole substrate. The highest PD concentrations were 35.86±0.19 g/L and 31.65±0.44 g/L with the yield of 0.76 and 0.7 for pure and biodiesel based glycerol, respectively when the bioreactor was maintained with inlet glycerol of 60 g/L and dilution rate of 0.3 hr-1. The steady state result also suggested the possibility of using biodiesel based glycerol as the substrate for this process but still recommended removing the purity before being used. In the second part, the research explored several options for reducing the PD production expense including dilution of media to 5 and 10 folds of the original formula, lowering the purity of media reagent to industrial grade, changing the nitrogen source from yeast extract to urea, L-lysine, ami-ami, and ammonium sulfate, and finally changing the mass ratio of inorganic to organic nitrogen in the original media formula to 1:11, 1:16, and 1:34, while maintaining the constant total nitrogen. The result indicated that, for the initial glycerol concentration of 40 g/L, the steady state PD concentrations were 19.81±0.13 g/L, 11.32±0.26 g/L, 5.28±0.11 g/L, 13.88±0.05 g/L, 15.80±0.15 g/L, 10.79±0.21 g/L, 9.68±0.08 g/L, 12.79±0.21 g/L, 7.03±0.42 g/L, 10.15±0.09 g/L, and 5.67±0.62 g/L for original media formula, 5-times dilution, 10-times-dilution, industrial grade reagents, urea, ammonium sulfate, L-lysine, ami-ami, 1:11 inorganic/organic nitrogen ratio, 1:16 inorganic/organic nitrogen ratio, and finally 1:34 inorganic/organic nitrogen ratio, respectively. The result also pointed out that dilution and lowering the purity of the reagents led to decreasing PD concentrations, a trend that is similar to those when changing the nitrogen source and changing the mass ratio of inorganic to organic nitrogen. In addition, using industrial grade reagents significantly reduced production cost in comparison to employing the original media formula or selecting analytical reagents, thereby suggesting the possibility of application in an actual industrial scale production.
