Styrene is a naturally occurring organic compound found in floral scents of several plant species.It is also an important industrial monomer primarily used for production of polystyrene and a number of other co-polymers.Currently,more than 30 million metric tons of styrene is produced exclusively from petroleum every year.Here we report the biosynthesis of styrene by microbial fermentation using renewable materials.We identified two key enzymes for styrene biosynthesis,phenylalanine ammonia lyase (PAL) and ferulic acid decarboxylase (FDC).We have studied the kinetics of the two enzyme system,explored homologous enzymes,and established a fermentation condition to increase the catalytic efficiency.When the styrene biosynthesis is coupled to phenylalanine biosynthesis,the styrene accumulation increased dramatically and no feeding of phenylalanine is necessary.Further improvement of the styrene biosynthesis using renewable starting material will be discussed.