Chloroplast expression of myoglobin and functional characterization of C. reinhardtii biomass for alternative meat applications

Abstract

Myoglobin has been extensively studied as an alternative meat ingredient for its meaty flavour, colour, and texture properties. Extracting myoglobin from natural sources does not align with the animal-free criteria of alternative meat. Considering microalgae's nutritional value and GRAS status, myoglobin expression in C. reinhardtii eliminates the need for its extraction. This study aimed to develop myoglobin expressing transplastomic lines of C. reinhardtii and investigate the effect of using various light regimes on myoglobin content at the lab scale. Myoglobin of up to 0.258 mg·g⁻¹ of DCW was accumulated at shake-flask level. Studies at a 2 L bubble column bag reactor demonstrated a stable and scalable Myoglobin expression system. Further, the functional analysis of myoglobin-expressing C. reinhardtii biomass established its applicability as an alternative meat ingredient. The work demonstrates robust myoglobin expression and its application for the alternative meat industry.