PT  - JOURNAL ARTICLE
AU  - Lee, So-Hee
AU  - Lee, Sang-Soo
AU  - Kim, Chan-Wha
TI  - Changes in the Cell Size of <em>Brevundimonas diminuta</em> Using Different Growth Agitation Rates
DP  - 2002 Mar 01
TA  - PDA Journal of Pharmaceutical Science and Technology
PG  - 99--108
VI  - 56
IP  - 2
4099  - http://journal.pda.org/content/56/2/99.short
4100  - http://journal.pda.org/content/56/2/99.full
SO  - PDA J Pharm Sci Technol2002 Mar 01; 56
AB  - Brevundimonas diminuta (ATCC 19146) is a standard organism for validation of sterilizing-grade membrane filters. Cell size is critical for the determination of retention characteristics of 0.2 μm rated membrane filters. In this study, cell size changes of B. diminuta cultured under different physiologic states and variable agitations at 50, 100 and 200 rpm were measured by a particle size analyzer and scanning electron microscope (SEM). The smallest cells were obtained at initial stationary phase in saline lactose broth (SLB) as a shaking culture at 50 rpm. Cells grown under agitation at 50, 100 and 200 rpm showed an increase of specific growth rate (μ), about 2.9, 3.6 and 3.6 fold, respectively, compared to the non-agitated cells in SLB media. These results suggested that the cell size decreased proportionally with increase of the specific growth rate (μ) in SLB. These size changes were associated with penetration through a 0.2 μm rated cellulose acetate filter. A scale-down filtration system was developed and performed bacterial challenge test and bubble point test with cells cultured in SLB. Cells grown under agitation conditions in SLB were not retained by 0.2 μm rated membrane filter.