| dc.description.abstract | The objective of this study was to establish a culture of Beta vulgaris L. developing in bioreactor, under fed-batch regime (CLA), for the production of arabinogalactan-proteins (AGPs). CLA regime considered the use of pH-stat control and sucrose as carbon source. Batch culture (CL) of B. vulgaris was performed, and the next kinetic parameters were obtained: maximal biomass concentration (XCL = 12.15 g DW L-1), specific growth rate (μ) of 0.21 d-1, AGPsCL production (67.42 mg L-1), biomass yield to sucrose consumed (Yx/s= 0.336 g cells g-1 of sucrose), AGPs yield to sucrose consumed (YAGPs/X= 4.92 mg AGPs g-1 of biomass) and AGPs productivity (QAGPs= 0985 mg L-1 d-1). A consume of 72.13 mL of HCl was necessary in order to maintain the pH broth in 5.5 during the kinetic. The parameters obtained from the CL (YX/S and YAGPs/X), the relation between the HCl feed and sucrose residual (R2 = 0.89) were used to essay different concentrations of sucrose (50 to 400 g L-1) using the equations of CLA. Sucrose concentration of 300 g L-1 was the best condition to improve of biomass (1.64 fold) and AGPs (1.66 fold). The CLA of B. vulgaris in bioreactor, with the pH-stat control with 300 g sucrose L-1 in the feed stream was conducted. Production XCLA and CLAAGPs was 20.65 g PS L-1 and 143.84 mg L-1 with a μCLA of 0.55 d-1, the HCl and sucrose consumption was 48.73 mL. Under CLA YAGPs/X was 8.01 mg g-1 and QAGPs was 2.0 mg L-1 d-1, 46.9 mL of HCl was necessary to control the pH broth in 5.5. The CLA reached the stationary phase at day 4; however AGPs production presents a trend to increase. In consequence, CLA was continued at day 9; results showed a reduction of biomass concentration (11.52 g DW L-1), while AGPs production increased to 491.46 mg of AGPs L-1 (7.2 fold to CL). The sucrose fed was not consumed by the cell and it was accumulated in the broth (45 g sucrose L-1). This condition could be an osmotic stress that induces the secretion of AGPs by the cell in the culture medium. Results of this work using the CLA are pioneer with B. vulgaris cell growing in bioreactor, and particularly to produce AGPs. The technique of CLA improve AGPs production 7.2 fold up in relation with CL. | |
