FORMATION OF MELANIN PIGMENT BY A MUTANT OF BACILLUS-THURINGIENSIS H-14

A mutant of Bacillus thuringiensis H-14 produced a dark brown pigment during sporulation. Production of the pigment depended on the nutritio nal properties of the growth medium. The pigment was identified as mel anin, based on chemical tests and its infra-red spectrum. Incorporatio n of L-tyrosine in the culture medium enhanced the level of melanin pr oduction, and L-3,4-dihydroxyphenylalanine (L-DOPA) was detected in th e culture broth during the late-exponential phase of growth. This indi cates that the pathway of melanin synthesis is from L-tyrosine, via L- DOPA, to melanin.