H2 



Marine Microbiology 



THIAMINE 



6 12 18 24 6 12 18 24 



TIME AFTER i NOCULATION- HRS 



Fig. 3. Production of an antibiotic substance and B vitamins by culture 



P9, a marine Serratia obtained from Puerto Rico. Note that this bacterium 



excretes thiamine, along with other B vitamins. 



