Research on Search of the Carotenoid-producing Microorganisms in Marine Area and the Improvement of Production Ratio

Abstract

Carotenoids are liposoluble pigments widely distributed in nature. More than 750 carotenoids are isolated from natural sources, but only a few kinds are used industrially. The production of carotenoid by microorganisms is to be expected, but few carotenoids originate from living things on land. And there is little knowledge about carotenoid-producing microorganisms in the oceans. The possibility still exists of discovering new carotenoid-producing microorganisms. Sunlight is very strong in subtropical regions. The surface of the sea and coral reefs in these regions is a severe environment for growth of microorganisms. While such conditions produce reactive oxygen species, the continuing strong irradiation can also lead to damaging and lethal photo-oxidative reactions. Many undiscovered microorganisms may possess protective mechanisms such as anti-oxidative activities for survival in this environment. This study focused on marine microorganisms inhabiting coral reefs in the Okinawa area, especially carotenoid-producing bacteria possessing anti-oxidative activities. Many carotenoid-producing microorganisms were collected from subtropical ocean areas (a total of 334 strains of pigmented microorganisms), and the chemical composition, some culture conditions and genetic characteristics of the carotenoids from these microorganisms were examined. Furthermore, similar research was performed using some creatures from the ocean surrounding Kochi Prefecture.