Growth dynamics of Artemisia annua hairy roots in three culture systems

Abstract

The transient growth of Artemisia annua hairy roots was compared for cultures grown in shake flasks and in bubble column and mist reactors. Instantaneous growth rates were obtained by numerically differentiating the transient biomass measurements. Specific sugar consumption rates showed good agreement with literature values. From the growth rate and sugar consumption rate, the specific yield and maintenance coefficient for sugar were determined for all three culture systems. These values were statistically indistinguishable for roots grown in shake flasks and bubble columns. In contrast, the values for roots grown in bubble columns and mist reactors were statistically different, suggesting that sugar utilization by roots grown in these two systems may be different. By measuring respiration rates in the bubble column reactor we also determined the actual biomass yield and maintenance coefficient for O(2) and CO(2). Together with an elemental analysis of the roots, this allowed us to obtain a reasonable carbon balance.

Using an aerosol deposition model to increase hairy root growth in a mist reactor

“…Growth requires energy, and the major portion of stored energy in plants is found in the form of carbohydrates. In particular, A. annua roots are >40% (w/w) carbon as determined by elemental analysis (Kim et al, 2003). The apparent biomass yield (Y X/S ) of transformed roots of A. annua in shake flasks is approximately 0.34 AE 0.00 g DW/ g glucose equivalent in 3% sucrose and 0.32 AE 0.03 in 5% sucrose (Fig.…”

“…While few data are available on the whole plant carbon content of different species (Poorter and Bergkotte, 1992), the carbon content is said to range from 390 to 550 mg g À1 (Poorter, 1989). Carbon is the predominant source of energy, and the dry biomass of A. annua (Kim et al, 2003) and H. muticus hairy roots (Ramakrishnan et al, 1999) is about 40% carbon. Using the small mist reactor, A. annua hairy roots were fed medium containing 3 or 5% sucrose at the standard mist duty cycle (15 min on, 15 min off).…”

“…If we assume an apparent biomass yield of 0.35 g DW produced per g sugar consumed (Kim et al, 2003), complete consumption of the available sugar should increase the biomass by 0.55 g DW corresponding to a growth rate of 0.08 day…”

“…Fructose, glucose, and sucrose were used as standards. Nitrate concentrations were analyzed spectrophotometrically as described in Kim et al (2003). Standard solutions were made from KNO 3 .…”

Production of mouse interleukin‐12 is greater in tobacco hairy roots grown in a mist reactor than in an airlift reactor

“…Nitrate, ammonium, phosphate and residual sugars were assayed using the methods described by Kim et al (2003), Towler et al (2007), and Dubois et al (1956). Total soluble protein in the biomass and medium was measured using a Coomassie Protein Assay Kit (Pierce, Rockford, IL) with bovine serum albumin as the standard.…”