Acta Biológica Colombiana
Print version ISSN 0120-548X
CASTELLANOS, ANGÉLICA et al. Physico-Chemical Parameter for Production of Lactic Acid or Ethanol of (Corynebacterium glutamicum) Bacteria. Acta biol.Colomb. [online]. 2011, vol.16, n.2, pp. 100-200. ISSN 0120-548X.
The interest to obtain products for the bio-fuel industry from renewable resources has directed research to find resistant and costs-effective biotechnological systems. Corynebacterium glutamicum, is a microorganism used to produce amino acids, that grows in wide variety of substrates and its resistance during fermentation to pH, temperature, osmotic pressure variations and alcohol aggregate, renders this organism a suitable candidate to improve by genetic modifications lactic acid and ethanol synthesis. However, some aspects of its physiology remain unknown, such us increase lactic acid and ethanol production from C5 and C6 sugars. For this reason, the main aim in our work was to identify the most important variables with impact on culture and the best culture conditions to produce lactic acid or ethanol in batch culture. To achieve this objective, eight variables were tested in culture using a statistical model. The best culture conditions were obtained and tested in a bacth biorreactor system. Temperature, biotin and glucose concentration were the variables with most impact (p< 0.05) in culture. Using optimal conditions, 36 °C; 6.1 mg/L of biotin and 50 g/L of glucose; a µmax of 0.394 h-1, 16 g/L of lactic acid was obtained after 15 h of culture with an efficiency of 32%. High glucose consumption was observed during bacterial growth, which leads to low concentration of substrate for the production process; this suggests a culture feeding at the end of exponential growth phase, which can increase the production yield.
Keywords : Fermentation; Corynebacterium glutamicum; Batch culture; Lactic acid.