Forouzan Rostami - Department of Food Science & Engineering, University of Tehran, Karaj, Iran
Seyed Hadi Razavi - Department of Food Science & Engineering, University of Tehran, Karaj, Iran
Abbas Akhavan Sepahi - Department of Microbiology, Faculty of Science, Islamic Azad University,North Branch of Tehran, Iran

The interest in production of natural colorants by microbial fermentation has been currently increased. Effect of three keyparameters including glucose concentration, aeration and inoculation intensity on the production of biomass dry weight(BDW), total carotenoid (TCt) and canthaxanthin (CX) by Dietzia natronolimnaea HS-1 in a batch bioreactor by applyingrandomized complete block design (RCBD) was scrutinized. Results of analysis of variance (ANOVA) revealed that theyield of BDW, TCt and CX was significantly affected by the investigated parameters (p< 0.01). The CX concentration wasimproved by increasing air-flow rate due to the suitable distribution of oxygen and glucose in the culture medium. The initiallag phase of growth was considerably decreased by increasing the inoculum size. The most suitable combination of variablesfor higher production of BDW (7.81 g/l), TCt (4764.8 μg/l) and CX (4329.7 μg/l) by D. natronolimnaea HS-1 was glucosecontent of 30 g/l, aeration rate of 10 l/1/min and inoculation density of 42×109 CFU cells/ml.

Dietzia natronolimnaea HS-1, Enhanced biomass, Air-flow rate, Inoculum size