Acetone-based lysis of marine purple photosynthetic bacterium, Rhodovulum sulfidophilum, for efficient biomass...

Marine purple photosynthetic bacteria, such as Rhodovulum sulfidophilum, are emerging as promising resources for sustainable biotechnological and agricultural applications, due to their capacity to produce high-value compounds and serve as nitrogen-rich organic fertilizer. For their integrated use in these applications, it is essential to develop compatible lysis methods superior to existing methods in terms of stability, scalability, and efficiency. This study evaluated the use of a readily available polar solvent, acetone, for the lysis of R. sulfidophilum. Acetone effectively lysed the cells while maintaining the total nitrogen (inorganic and amino acid) and carotenoid profile similar to intact cells. In comparison, cells that were lysed mechanically using ultrasonication and high pressure contained higher inorganic nitrogen content, particularly nitrate. Acetone lysis also demonstrated distinct advantages over high-pressure homogenization and ultrasonication mainly due to (1) reduced processing time, which helped preserve the integrity of sensitive biomolecules such as carotenoids, namely spheroidenone which constituted ∼83 % of total carotenoids, and (2) lower energy and time requirements for drying, making the process more energy-efficient. These findings demonstrate acetone lysis as a simple, effective, and economical approach for lysis of R. sulfidophilum, which preserves nitrogen and carotenoid composition better than mechanical lysis methods for both biomass-based and biotechnological applications.