Seed oils from cultivated plants have long been used as raw material sources for biodiesel production. Recently, however, attention has shifted to the use of microorganisms (particularly photosynthetic microorganisms) as potential oil sources for biodiesel production. One such type of microorganism under study is a class of photosynthetic bacteria, called "cyanobacteria". Since the oil produced by these microorganisms is generally an intracellular product, the cell walls have to be destroyed by application  of physical or chemical means (such as ultrasound, high pressure, or use of chemicals) Cell wall disruption often entails a high oil recovery cost. Researchers from the Arizona State University (ASU, United States) have developed a way to reduce the cost of oil recovery from cyanobacteria, by programming it to "self-destruct". The programmed autolysis is induced by the addition of nickel; autolysis eventually liberates the intracellularly-trapped oil without further addition of physical or chemical recovery processes. The ASU press release gives an overview of the method: "The genes were taken from a mortal bacterial enemy, called a bacteriophage, which infect the bacteria, eventually killing the microbes by causing them to burst like a balloon. The scientists swapped parts from bacteriophages that infect E. coli and salmonella, simply added nickel to the growth media, where the inserted genes produced enzymes that slowly dissolved the cyanobacteria membranes from within". The full paper is recently published in the Proceedings of the National Academy of Sciences (PNAS) (URL above)..