Method for screening and quantifying isoprene biosynthesis enzyme activity

A method of detecting, screening or quantifying the activity of one or more isoprene biosynthesis enzymes using an artificial genetic circuit, the method comprising the steps of:

• (a) providing an artificial genetic circuit for detecting isoprene or microorganisms containing in their chromosomal DNA or cytoplasm an artificial genetic circuit for detecting isoprene, the artificial genetic circuit comprising:
• (i) a gene encoding an isoprene-sensing transcriptional regulator which recognizes isoprene,
• (ii) at least one reporter gene selected from the group consisting of fluorescence protein-encoding genes and antibiotic resistance genes, and
• (iii) a gene expression regulatory region consisting of a promoter regulating the expression of the isoprene-sensing transcriptional regulator, a region to which the isoprene-sensing transcriptional regulator binds to induce the expression of a downstream reporter gene, and a promoter regulating the expression of the reporter gene;
• (b) providing a clone or gene library containing one or more of a gene encoding an isoprene biosynthesis enzyme;
• (c) introducing the clone or gene library and the artificial gene circuit for detecting isoprene into host microorganisms to prepare recombinant microorganisms or introducing the clone or gene library into the microorganisms containing the artificial gene circuit or detecting isoprene to prepare recombinant microorganisms;
• (d) treating the recombinant microorganisms with a compound capable of liberating isoprene by an enzymatic reaction;
• and
• (e) detecting or quantifying the activity of the reporter protein whose expression is induced by sensing isoprene liberated by the enzymatic reaction.