Effects of pulse feeding of beet molasses on recombinant benzaldehyde lyase production by Escherichia coli BL21(DE3)

2009-11-01
Çalık, Pınar
Levent, Hande
The effect of fed-batch operation (FBO) strategy was investigated using pretreated-beet molasses, containing galactose that induces the lac promoter, on benzaldehyde lyase (BAL) production by recombinant Escherichia coli BL21(DE3)pLySs. After batch cultivation with 30 g l(-1) pretreated-beet molasses consisting of 7.5 g l(-1) glucose and 7.5 g l(-1) fructose, three FBO strategies were applied at dissolved oxygen (=40%) cascade to air-flow rate. In FBO1 when air-flow rate decreased considerably, feed was given to the system in pulses in such a way that pretreated-beet molasses concentration increased by 10 kg m(-3) (containing 2.5 g l(-1) glucose+2.5 g l(-1) fructose); however, decrease in air-flow rate demonstrated only the absence of glucose but not fructose. Thus, in FBO2 when fructose and glucose were completely utilized, pretreated-beet molasses was pulse-fed and its concentration increased by 10 g l(-1). In FBO3 with the decreased amount of pretreated-beet molasses (6 g l(-1)), shift response time from glucose to fructose consumption was avoided, and glucose and fructose consumptions were well correlated with air-flow rate, and the highest C (X) (8.04 g l(-1)) and BAL (2,315 U ml(-1)) production were obtained (t = 24 h) with the highest substrate yield on cell and product formation.

Citation Formats
P. Çalık and H. Levent, “Effects of pulse feeding of beet molasses on recombinant benzaldehyde lyase production by Escherichia coli BL21(DE3),” APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, vol. 85, no. 1, pp. 65–73, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37394.