The Cambridge iGEM2010 team built a set of BioBricks to allow bioluminescence in a wide range of colours which have applications both as reporters for biosensors and as natural light sources. They adopted a number of strategies to extend the use of firefly luciferase: (i) codon optimisation for increased light output, (ii) use of a luciferin regenerating enzyme and (iii) mutagenesis to create a number of different colours. The team also created a BioBrick version of the Vibrio fischeri Lux operon which results in light emission in E. coli without the need for addition of any external substrate. This produces a high light output (as demonstrated by Ben Reeve and Theo Sanderson above!)