Enhancing fucoxanthin production in Chaetoceros calcitrans under mixotrophic condition and LED wavelength shift strategy

Abstract

This study addresses the challenge of achieving high fucoxanthin (Fx) productivity in Chaetoceros calcitrans under mixotrophic cultivation which often struggle to simultaneously increase biomass and Fx content. To overcome this, we investigated the potential of C. calcitrans for Fx production under mixotrophic conditions by investigating the interaction of organic carbon, light intensity, and light emitting diode (LED) color shifts during cultivation to optimize Fx production. Results revealed significant influences of various organic carbon sources on Fx productivity, with glycerol and glucose showing promising outcomes. Furthermore, the addition of external urea enhanced Fx content in mixotrophic cultivation. Response Surface Methodology (RSM) analysis highlighted the synergistic effect of light intensity and glycerol addition on Fx productivity. Most notably, shifting from white to blue LED during mixotrophic cultivation at the end of the exponential phase significantly increased Fx productivity in C. calcitrans to 3.2 mg L−1 d−1, representing a 1.3-fold enhancement compared to white LED sources. These findings underscore the potential of mixotrophic cultivation and LED color shifts as effective strategies for improving Fx productivity in diatoms.