การผลิตกรด 6-อะมิโนเพนนิซิลานิก ในหอปฏิกิริยาแบบฟลูอิดไดซ์เบด โดยใช้เซลล์ Escherichia coli ที่ถูกตรึง / นิวัฒน์ คุปต์วิวัฒน์ = Production of 6-aminopenicillanic acid in fluidized bed reactor by immobilized whole cells of Escherichia coli / Niwat KHupviwat
Escherichia coli ATCC 9637 can produce penicillin acylase which is commonly used for hydrolysis of Penicillin G yielding 6-aminopenicilanic acid (6-APA) as the starting material for further synthesis of penicillin derivatives. The appropriate techniques and conditions was used to immobilized whole cell of E. coli by entrapping in agar, kappa carrageenan and mixture of agar-carrageenan. Immobilization of E. coli cells (10-15% w/v). The entrapment of cells in the mixture of carrageenan to agar 2.5 : 1.5% w/v were performed and implemented with 0.1 M glutaraldehyde and hexamethylenediamine. The strength of cell immobilized by agar-carrageenan exhibited 2 and 3 folds higher than the carrageenan and agar respectively, while the recovery activity of the immobilized cells was about 65-70% in relative to the original free cells. The gels established higher optimum temperature than the free cells (50-55℃). There was no difference in optimum pH. The pH stability of the gels was obviously higher and rather broader when comparing to the unimmobilized one (pH 5.0-9.0). There was no significant change in the penicillin acylase activity when immobilized cells were kept in 0.3 M KCI at 4 and 27℃ for 50 days. Alternately stored the gels at 4℃ and utilized them in the fluidized bed reactor (24 hours per run at room temperature) for 17 rounds did not show any loss of the enzyme activity. The activity of the immobilized cells to produce 6-APA was investigated in fluidized bed reactor (1.2 litres volume). The suitable conditions were established as followings: immobilized cells (agarcarrageenan) 135 grams and Penicillin G concentration of 0.47 gram-percent. The flow rate of the substrate solution was 80 ml/hr with air rate about 2-3 litres/min. Under these selected conditions, the reactor could be operated continuously for 5 days without and loss in the 6-APA production.