Sustainable protein production from mallow leaves by lactic acid bacteria as a green alternative protein

Mallow leaves ( Malva sylvestris L.) have emerged as a promising sustainable protein source due to their high protein and essential amino acids content. However, challenges in optimizing extraction methods persist. This study investigates protein precipitation by using the lactic acid bacteria (LAB) fermentation process, as an innovative, eco-friendly method, and direct lactic acid treatment to enhance protein precipitation. Six selected strains of LAB were evaluated for their efficiency in protein extraction from mallow leaves, and their effectiveness was compared with that of direct lactic acid treatment. The results of fermentation with LAB strains under conditions 39 ± 1°C for 24 h, and lactic acid treatment; followed by protein precipitation and purification, indicated that the cured protein ranged from 61.03% to 78.50 %, the total amino acids ranged from 343.47 ± 21.39 to 396.30 ± 6.61 mg/g, and the protein recovery yield ranged from 52.31% to 67.31%. Strain Lp. plantarum PQ475926 which was isolated from traditional fermented milk recorded the highest cured protein 78.50 %, total amino acids 396.30 ± 6.61 mg/g and protein recovery yield 67.31%. SDS-PAGE analysis demonstrated distinct protein bands at defined molecular weights of 15 to 60 kDa, with noticeable variation across the LAB strains. These findings suggest that the extraction method based on LAB fermentation can significantly enhance protein yield and quality, supporting the development of sustainable, high-quality protein sources for food fortification and functional ingredient applications.