Optimization of a two-phase culture system of Chlamydomonas hedleyi using light-emitting diodes and potential as a biodiesel feedstock

Abstract

In this study, the parameters of microalga culture were optimized to maximize the biomass and lipid production of Chlamydomonas hedleyi. Experiments were performed using a two-phase culture system. In the first phase, the nitrate concentration, LED photoperiod, and light intensity were optimized for maximal biomass production. In the second phase, the LED photoperiod and light intensity under nitrate starvation conditions were optimized to induce maximal lipid production. During the first phase of culture, a biomass of 0.95 g DCW/L and the shortest cultivation time were obtained with a nitrate concentration of 240 mg/L, under a 24:0 h light:dark cycle, and a light intensity of 500 µmol m−2 s−1. In the second phase of culture, a maximum lipid content of 41.3% was obtained with a light:dark cycle of 12:12 h and a light intensity of 400 µmol m−2 s−1 under nitrate starvation conditions for 2 days. C. hedleyi lipids meet international biodiesel standards, such as cetane number, iodine value, and oxidative stability. This study contributes to the related literature by providing information on C. hedleyi and evaluating its potential as a biodiesel feedstock.