Mammalian perfusion cultivation at high L-Arginine concentration for efficient production of recombinant protein by increasing perfusion filter transmission.

Cultivations of Chinese Hamster Ovary (CHO) cells in a perfusion setup were conducted in the presence of super physiological concentrations of L-Arginine to investigate the impact on transmission through the perfusion filter for production of a recombinant domain antibody. Our study revealed that the presence of L-Arginine within the range of 30-50 mM had a positive impact on transmission. However, the higher concentrations were found to have a negative correlation with cell viability, and an optimal concentration of approximately 40 mM was identified.

Determination of first order rate constants by natural logarithm of the slope plot exemplified by analysis of Aspergillus niger in batch culture.

Finding rate constants from experimental data is often difficult because of offset and noise. A computer program was developed to average experimental data points, reducing the effect of noise, and to produce a loge of slope plot--a plot of the natural logarithm of the slope of a curve--eliminating the effect of any offset. If y-values depend exponentially on x-values the loge of slope plot is rectilinear and the slope is equal to the first order rate constant.