Shear Index로 표시된 E.coli Floc의 강도

김찬화; 나초균

Korean Journal of Rheology, Vol.8, No.3-4, 226-231, December, 1996

Export Citation

Shear Index로 표시된 E.coli Floc의 강도

Strength of E. coli Floc as Indicated by Shear Index

김찬화, 나초균

초록

침강제에 의해 형성된 E. coli floc들의 강도를 측정하기 위해 floc의 shear index를 측정하였다. 형성된 E. coli floc은 10/sec 같이 낮은 shear rate에서도 분쇄되거나 변형 되었다. 측정된 shear index의 감소에서 보듯이 E. coli floc의 강도는 염의 농도가 증가함에 따라 감소하였다. E. coli floc의 shear index는 NaCl의 농도가 0에서 100mM로 증가함에 따라 0.47에서 0.09로 줄었다. 발효배지의 조성에서 형성된 E. coli floc들은(shear index=0.18-0.24 with BPA-1000, 0.13-0.22 with BPA-1050, and 0.37-0.42 with BPA-5020) 염이 없을 때 형성된 floc에(shear index=0.47 with BPA-1000 and 0.46 with BPA-1050) 비해 약하였다. 따라서 발효배지에서 형성된 floc은 생물공정 중 쉽게 shear에 의해 분쇄되거나 변형될 것이다.

The strength of E. coli flocs formed with flocculants was quantified by measuring the shear index. E. coli flocs formed were disrupted or deformed at the shear rate even below 10/sec. The strength of the E. coli flocs decreased with increases in the concentration of salt as indicated by decreases in the shear index. The shear index of the E. coli flocs decreases from 0.47 to 0.09 when the concentration of NaCl increased from 0 to 100 mM. The E. coli flocs formed with various flocculants in fermentation media (shear index= 0.18 to 0.24 with BPA-1000, 0.13 to 0.22 with BPA-1050, and 0.37 to 0.42 with BPA-5020) were weaker than those formed with flocculants in the absence of salt (shear index=0.47 with BPA-1000 and 0.46 with BPA-1050) Therefore. E. coli flock formed with flocculants in fermentation media will be easily disrupted or deformed under shear during bioprocesses.

Keywords:Roc strength;shear index;flocculant;shear rate dependency;cell debris removal.

[References]

Kim CW, Kim SK, Rha CK, Robinson E, "Flocculation in Biotechnology and Separation Systems," ed by Y.A. Attia, Elsevier Science Publishers, B.V., Amsterdam, p. 429 (1987)
Kim CW, J. Inst. Biotechnol. Korea Univ., 7, 53 (1995)
Krijgsman IJ, "Product Recovery in Bioprocess Technology," Thomson Litho Ltd., East Kilbride, Scotland (1992)
Wang DIC, Cooney CL, Demain AL, Dunnill P, Humphrey AE, Lilly MD, "Fermentation and Enzyme Technology," John Wiley & Sons, New York (1979)
Craven CR, Stters E, Anfinsen CB, J. Biol. Chem., 240, 2468 (1965)
Kelmers AD, Hancher CW, Phares EF, Novelli GD, Mothods Enzymology, 20, 3 (1971)

[1] Kim CW, Kim SK, Rha CK, Robinson E, "Flocculation in Biotechnology and Separation Systems," ed by Y.A. Attia, Elsevier Science Publishers, B.V., Amsterdam, p. 429 (1987)

[2] Kim CW, J. Inst. Biotechnol. Korea Univ., 7, 53 (1995)

[3] Krijgsman IJ, "Product Recovery in Bioprocess Technology," Thomson Litho Ltd., East Kilbride, Scotland (1992)

[4] Wang DIC, Cooney CL, Demain AL, Dunnill P, Humphrey AE, Lilly MD, "Fermentation and Enzyme Technology," John Wiley & Sons, New York (1979)

[5] Craven CR, Stters E, Anfinsen CB, J. Biol. Chem., 240, 2468 (1965)

[6] Kelmers AD, Hancher CW, Phares EF, Novelli GD, Mothods Enzymology, 20, 3 (1971)