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Suspension cells of kidney bean were grown for 42 d in MS medium supplemented with growth regulators (2.0 mgL-1 2,4-D and 0.5 mgL-1 kinetin) or without At the stationary growth phase (42 d), the sugars were fractionated into the symplastic (ethanol and starch) and apoplastic [low-molecular pectin (lm-pectin), high-molecular pectin (hm-pectin), hemicellulose, and cellulose] sugars. The neutral sugars (NS) of hm-pectin and hemicellulose fractions were analyzed by GLC. The growth of the suspension cells in the liquid MS media, in terms of settled cell volume (SCV), remained similar, to the end of the experiment, irrespective of the presence or absence of growth regulators, indicating the nonnecessity of the exogenous growth regulators for the subculture. Total sugar (TS) of the ethanol fraction and NS of the Im-pectin of the suspension cells grown in the medium with growth regulators were higher than in the medium without growth regulators. However, starch content in the starch fraction and uronic acid (UA) content of the Im-pectin fraction did not exhibit any differences. From these results, it was suggested that the growth regulators modulated the structure of the cell wall polysaccharide. Analysis of the NS composition of the hm-pectin fractions revealed that the Rha, Arb, and Gal contents in the presence of growth regulators were higher than in the absence, while the Xyl, Man, and Glc contents in the presence of growth regulators were higher than in the absence, indicating the turnovers of rhamnogalacturonan and/or arabinogalactan. On the other hand, analysis of NS composition of hemicellulose fractions revealed that the Ara and Glc contents in the presence of growth regulators was higher than in the absence, whereas Xyl and Glc contents were nearly consistent, indicating the turnovers of arabinaogalactan I or II. The cellulose contents remained similar, irrespective of the presence (19.1%) or absence (18.7%) of growth regulators.

We cultured the suspension cells of kidney bean in MS media supplemented with one of five concentrations of CaCI2 [0,22,44 (control), 88, or 176 mg/L], and harvested them at the logistic (15 d) and early-stationary (30 d) phases. Cells grown at concentrations higher than 22 mg/L showed better proliferation than those at 0 mg/L The rate of proliferation also increased with higher concentrations. We fractionated the individual sugars into symplastic (EtOH and starch) and apoplastic (low-molecular pectin, high-molecular pectin, hemicellulose, and cellulose) components. Cells treated at the highest concentration (176 mg/L) exhibited the greatest amount of sugar in the EtOH and starch fraction during the logistic phase. In contrast, cells in the early stationary phase had the highest level of sugar at treatment concentrations of less than 22 mg/L. For treatment concentrations higher than 22 mg/L on Day 15, more pectin and hemicellulose was detected at greater amounts compared with those cells treated with 0 mg/L. However, at Day 30, concentrations higher than 44 mg/L induced greater amounts of pectin and hemicellulose than from the other concentrations. Cellulose was more abundant with the 0 mg/L treatment, and contents ranged from 17.4 to 25.5% in the primary cell walls over all treatment concentrations. These results indicate that CaCI2 modulates both symplastic and apoplastic sugar metabolism. Therefore, we suggest that the cell-wall structure may define the mode of polysaccharide biosynthesis during cell growth.

To maintain a constant specific growth rate for a recombinantS.cerevisiae in fed-batch, the medium feeding rate has been controlled with respect to the hourly calculated glucose uptake rate. The recombinant yeast producing HBsAg showed the exponential production trend in proportion to the exponential cell growth. Total cell yield in fed-batch was about 0.402 g cells/g glucose, and HBsAg was produced about ten times more than in batch. Decrease of growth rate by HBsAg produced was not shown.