Optimizing NaCl and KNO3 Concentrations for High b-carotene Production in Photobioreactor by Dunaliella salina KU11 Isolated from Saline Soil Sample

Abstract

The unicellular alga Dunaliella salina is a well-known, interesting cell factory for the commercial production of b-carotene. In Thailand, cultivation of D. salina for b-carotene production has not yet been studied extensively. In this study, D. salina KU11 was isolated from the saline soil samples of Chiyamphum province, Thailand. To investigate the optimal salinity and nitrate concentration for the highest b-carotene accumulation, D. salina KU11 isolate was grown in modified Johnson’s media with different salinities (from 1.0 to 3.5 M NaCl) and different nitrate concentrations (from 0.25 to 1.0 g/l). b-carotene concentration was determined by HPLC-MS. The highest b-carotene content (115.5±0.4 mg/ml and 91±2 pg/cell) was obtained using modified Johnson’s medium containing 2.5 M NaCl and 0.5 g/l KNO3.