Crystal ball – 2013

In this feature, leading researchers in the field of environmental microbiology speculate on the technical and conceptual developments that will drive innovative research and open new vistas over the next few years. No review of the power of synthetic biology is complete without a sage affirmation that the fight for environmental protection will be immeasurably served by synthetic microorganisms. Yet, to state the obvious, environmental protection occurs in the environment and synthetic biology occurs in the test tube. Culture and culturability are the original sin of synthetic biology. The field of microbial ecology has blossomed under the insight that the Petri dish is but a pale and partial shadow of real microbial environments. Yet synthetic biologists, who seek to do better than evolution, use that tiny fraction (lets say 0.0001%) of evolutions handiwork that will grow in the lab. The implicit assumption is that in many cases it will be easier, or indeed absolutely necessary, to meet an environmental need, by creating novel a life form in the lab rather than using some pre-existing organism 'off the peg'. This is an assumption that is far more likely to be met if you only consider the organisms that grow in the lab and ignore competing philosophies such as microbial resource management. However, this 'diversity blindness' is not the biggest issue. Indeed it would require churlish counter-hubris to assume that someone somewhere could not engineer an organism with a useful function not found in nature. The question is how to deploy it. There is little evidence that we can get an organism from the laboratory into the field in any kind of systematic way. Those mindful of the fears of rampant microbes have spoken of forms of genetic containment, sequencing tweaks that would ensure the demise of a released but unwanted organism. They hardly need bother. Genetically manipulated (and I suspect cultured organism in general) seem to simply die away when faced with the rigours of the environment. Containment is problematic. Mark van Loosdrecht has pointed out that a sterile and sterilizable reactor (i.e. a very big test tube) will cost 200 times more than an equivalent open reactor. Moreover, the feedstock for such a reactor, presumably the waste itself, would need to be sterilized before use. Immobilization and protection behind membranes will be no less expensive. The simple truth is that it that virtually no one has successfully introduced a cultured …