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Self-Destructing Bacteria Create Better Biofuels
MikeChino writes "Researchers at Arizona State University have genetically engineered cyanobacteria to dissolve from the inside out, making it easy to access the high-energy fats and biofuel byproducts located within. To do this they combined the bacteria's genes with genes from the bacteriaphage — a so-called 'mortal enemy' of bacteria that cause it to explode. Cyanobacteria have a higher yield potential than most biofuels currently being used, and this new strain eliminates the need for costly and energy intensive processing steps."
Science Daily has the full press release which is a bit more informative: Genetic engineering feat could greatly reduce costs and the full paper is at the Proceedings of the National Academy of the Sciences: Nickel-inducible lysis system in Synechocystis sp. PCC 6803 (if you have access that is).
No, the 11% max. figure is for just turning sun's energy into hydrocarbons. If you want to generate electricity out of it, like in a bio-mass power plant, the thermodynamic losses would be on top of that so the efficiency would be considerably lower.
It's properly spelled bacteriophage--which are viruses of bacteria. These viruses make bacteria 'explode' so that newly replicated virions are released into the environment.
A loss of function mutation in a yeast used for brewing or a yogurt culture would be a big problem, just not as sensational as a kill the consumer mutation. Yet maintenance and selective breeding of cultures has been manageable for centuries now.
By the time the survival aspect of the modification can come into play, the bacteria are already at a dead end. They are in the batch that is being processed to fuel. The survivors of the nickle treatment will be destroyed just as surely as those that didn't mutate. Yields will be monitored. A tank whose yield declines will be sterilized and re-seeded. Culture sources with poor yields will be destroyed and replaced by others that have bred true (or at least haven't mutated in a way we don't like), just like yeast cultures. Those that produce bad beer are destroyed.
Yes, they mutate a lot. Most of the mutations are a disadvantage. Of the remainder, most don't matter at all. Those that prove harmful to the purpose we culture them for are destroyed batch by batch. The very few that prove beneficial to our purposes are propagated.
In many ways, culturing for fuel production is easier. Unlike foods, we don't care if it has an "off" taste, just that it burns well after processing.
Consider, a brewing yeast that mutates so that it can oxidize alcohol for energy will find plentiful food as the others die out. By the end of the fermentation process they will easily dominate. However, they will produce nasty tasting beer. If the mutation happens in the culture rather than in the vat, the whole culture is discarded.