Presentation Information
[P02-265]Cultivation-Driven Pigment Reduction Strategies for Producing Low-Chlorophyll Microalgal Biomass for Food Biorefineries
○Hui Ju Kim1, Yeoung-Sang Yun1, Dae Geun Kim1 (1. Jeonbuk Nat'l Univ. (Korea))
Keywords:
Pigment remodeling,Two-stage cultivation,Chlorosis inductio,Low-chlorophyll microalgae,Upstream bioprocess optimization
Microalgae are considered promising protein sources for alternative meat applications due to their high nutritional value and sustainable production potential. However, the intrinsic presence of chlorophyll and accessory pigments remains a major limitation for food utilization, as intense green coloration negatively affects consumer acceptance. Conventional post-harvest pigment removal methods relying on physical or chemical extraction often result in protein loss or compromise the food-grade applicability of the biomass.
To overcome this limitation at the production stage, this study investigated cultivation-based strategies aimed at intrinsically reducing pigment content during biomass generation rather than relying on downstream processing. Three independent cultivation approaches were comparatively evaluated for pigment reduction efficiency while maintaining protein functionality.
Heterotrophic cultivation was first applied to suppress photosynthetic pigment synthesis. Consistent with previous observations, heterotrophic growth enabled significant biomass accumulation while reducing chlorophyll content in selected strains, particularly Chlorella vulgaris and Euglena gracilis, both of which maintained relatively high protein levels under organic carbon supplementation.
A two-stage cultivation strategy was further implemented to exploit stress-induced pigment remodeling phenomena commonly observed in microalgae. Following biomass production under optimal growth conditions, secondary cultivation was conducted under controlled stress environments to induce physiological responses such as chlorosis and stress-driven carotenogenesis. These adaptive responses are known to suppress chlorophyll accumulation or alter pigment composition as protective mechanisms against environmental stress. This approach aims to decouple biomass production from pigment synthesis by promoting controlled pigment attenuation during post-growth cultivation without reliance on downstream extraction processes.
Finally, gamma irradiation was employed to generate low-pigment mutants. Mutant screening identified strains exhibiting substantial reductions in chlorophyll a and b levels, and subsequent rounds of mutagenesis yielded variants showing further pigment attenuation relative to the wild type while maintaining growth capability.
Collectively, this study proposes an upstream bioproduction strategy integrating metabolic regulation, environmental modulation, and strain improvement to reduce pigment content while minimizing protein loss. The comparative evaluation of these cultivation routes provides a framework for developing low-pigment microalgal biomass suitable for scalable food biorefineries and alternative protein manufacturing.
To overcome this limitation at the production stage, this study investigated cultivation-based strategies aimed at intrinsically reducing pigment content during biomass generation rather than relying on downstream processing. Three independent cultivation approaches were comparatively evaluated for pigment reduction efficiency while maintaining protein functionality.
Heterotrophic cultivation was first applied to suppress photosynthetic pigment synthesis. Consistent with previous observations, heterotrophic growth enabled significant biomass accumulation while reducing chlorophyll content in selected strains, particularly Chlorella vulgaris and Euglena gracilis, both of which maintained relatively high protein levels under organic carbon supplementation.
A two-stage cultivation strategy was further implemented to exploit stress-induced pigment remodeling phenomena commonly observed in microalgae. Following biomass production under optimal growth conditions, secondary cultivation was conducted under controlled stress environments to induce physiological responses such as chlorosis and stress-driven carotenogenesis. These adaptive responses are known to suppress chlorophyll accumulation or alter pigment composition as protective mechanisms against environmental stress. This approach aims to decouple biomass production from pigment synthesis by promoting controlled pigment attenuation during post-growth cultivation without reliance on downstream extraction processes.
Finally, gamma irradiation was employed to generate low-pigment mutants. Mutant screening identified strains exhibiting substantial reductions in chlorophyll a and b levels, and subsequent rounds of mutagenesis yielded variants showing further pigment attenuation relative to the wild type while maintaining growth capability.
Collectively, this study proposes an upstream bioproduction strategy integrating metabolic regulation, environmental modulation, and strain improvement to reduce pigment content while minimizing protein loss. The comparative evaluation of these cultivation routes provides a framework for developing low-pigment microalgal biomass suitable for scalable food biorefineries and alternative protein manufacturing.
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