While trawling for info about oxidising phenylalanine I found this link
http://aem.asm.org/cgi/content/full/64/8/3009 (http://aem.asm.org/cgi/content/full/64/8/3009)
and thought it might be useful (assuming l. plantarum can be found) since benzaldehyde is a useful chemical.
Weighing the cost of L-phenylalanine against that of synthetic precursors like toluene or natural sources like Oil of Bitter Almonds, this proposal of yours seems, at best, expensive and wasteful.