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Nature Biotechnology asks a selection of leaders from across biotech to look at the future of the sector and make some predictions for the coming years.

In 2000, Gardner and Collins reported the construction of a fundamental genetic regulatory device, the bi-stable toggle switch, in E. coli. We report here our work on a natural extension of this powerful device, a tri-stable genetic toggle switch capable of switching among three stable states. Like the bi-stable switch, the tri-stable switch consists of repressible promoters that produce inhibitory proteins and requires only a transient pulse of chemical inducer to switch among stable states. Our proof-of-principal construct is designed to control the expression of three different fluorescent reporters using the pBad/AraC, pLacI/LacI, and pTetR/TetR systems; though a tri-stable switch can theoretically be constructed from any three repressible promoters that satisfy a certain mathematical relationship. We have modelled the system extensively, creating both a simple continuous deterministic model based on the work of Gardner and Collins (Gardner and Collins, 2000) and a more complex discrete stochastic model based on the work of Isaacs (Isaacs, 2003). The tri-stable switch, designed, modelled, and partially constructed as an iGEM 2006 project at Brown University, is to be composed entirely of Biobricked parts from the Registry of Standard Biological Parts. In addition to providing support for the iGEM hypothesis, the tri-stable toggle switch has implications for biotechnology and gene therapy.

This paper demonstrates the significant utility of deploying non-traditional biological techniques to harness available volatiles and waste resources on manned missions to explore the Moon and Mars. Compared with anticipated non-biological approaches, it is determined that for 916 day Martian missions: 205 days of high-quality methane and oxygen Mars bioproduction with Methanobacterium thermoautotrophicum can reduce the mass of a Martian fuel-manufacture plant by 56%; 496 days of biomass generation with Arthrospira platensis and Arthrospira maxima on Mars can decrease the shipped wet-food mixed-menu mass for a Mars stay and a one-way voyage by 38%; 202 days of Mars polyhydroxybutyrate synthesis with Cupriavidus necator can lower the shipped mass to three-dimensional print a 120 m 3 six-person habitat by 85% and a few days of acetaminophen production with engineered Synechocystis sp. PCC 6803 can completely replenish expired or irradiated stocks of the pharmaceutical, thereby providing independence from unmanned resupply spacecraft that take up to 210 days to arrive. Analogous outcomes are included for lunar missions. Because of the benign assumptions involved, the results provide a glimpse of the intriguing potential of ‘space synthetic biology’, and help focus related efforts for immediate, near-term impact.