A study published in *Frontiers in Science* has investigated the growth of myoglobin protein fibres within the chloroplasts of lettuce and tobacco plants. This research represents an advance on earlier plant and algal studies.
Professor Rodrigo Ledesma-Amaro, Academic Lead in Engineering Biology for Sustainability at Imperial College London, noted that demonstrating stable myoglobin production in plant chloroplasts, including in an edible crop, raises the possibility of using plants as scalable production platforms.
Professor Derek Stewart, Co-Director of the National Alternative Protein Innovation Centre (NAPIC), described the findings as an exciting step forward in proving that plants can make myoglobin in a stable and scalable way. He highlighted that the protein was recovered in a properly folded form and bound to heme, which is important for meat-like colour and flavour.
However, the study had some limitations, including incomplete holo-myoglobin formation and heme occupancy of about 35%. The research also relied heavily on one tobacco line, leaving robustness and food-functionality uncertain. Tobacco as an expression system also raises concerns due to its innate production of bioactive alkaloids.