Isolation and selection of carotenoid-producing bacteria from marine environment and determination of carotenoid extraction condition

The carotenoid is a natural pigment group, which is gradual of interest because of its essential biological activities and great production potentials such as using low-cost material and easy to apply on a large scale. For further development of natural carotenoid products, in this study, fourteen yellow, red, and orange pigment-producing marine bacterial strains were isolated from 25 seawater samples collected along coasts of Phu Quoc island (Kien Giang province), Vung Tau City (Ba Ria – Vung Tau province), Can Gio district (Ho Chi Minh city), and Thang Binh district (Quang Nam province). These isolates were identified belong to seven genera Micrococcus, Kocuria, Microbacterium, Brevibacterium, Bacillus, Rhodococcus and Exiguobacterium with 96.7% - 100% of 16S rRNA sequences identity. Based on carotenoid producing ability and UV-absorbance profile, three of the isolates including Micrococcus sp. 64A3a (yellow), Exiguobacterium sp. YT09 (orange) and Rhodococcus enclensis strain RSA3 (red) were selected for investigation of carotenoid extraction conditions. Methanol at concentration of 100% with ratio of 1 g bacterial cells/10 mL methanol is suitable conditions for extraction of red, orange and yellow pigments from the isolates.