Marine Streptomyces sp.T1027 obtained from South coast of India was discovered to produce and accumulate β-carotene under the influence of light in liquid shake flask culture. The accumulation of β-carotene was growth associated and controlled by light, aeration, carbon and substrate solubility. Starch was the ideal substrate for maximum growth (4.5-6.1 g l-1) and β-carotene accumulation (92-130 μg g-1). Rapid extraction was done in Dimethylsulphoxide, Methanol (1:1) Solvent mixture. The organism was sensitive to a variety of antibiotics; in turn it was able to inhibit the human pathogen Corynebacterium diphtheria. Commercial substrates with high soluble starch content were found to produce maximum biomass and β-carotene production.