Physiological and ecological characteristics of lipid-producing Botryococcus isolated from the Korean freshwaters = 한국산 고지질 미세조류 Botryococcus의 분포 및 생장 특성

Abstract

Recently, sustainable production of biofuel using algal biomass is being pursuedbecause of its enormous potential. First and foremost, securing superior strains to develop an efficientproduction system for algal biodiesel through screening or genetic improvement of microalgaeis necessary. The genus of Botryococcus is regarded as one of the superior microalgae for biodieselproduction due to its ability to accumulate high amounts of lipids and hydrocarbons. However, itslow growth rate is a bottleneck for large-scale production and commercialization. The purpose ofthis study is to obtain indigenous Botryococcus strains which possess high lipid content and biomassproductivity. The Botryococcus sp. was isolated from the Seobu Reservoir in Jeju Island and identifiedas Botryococcus sudeticus J2 by comparative analysis of 18s rRNA gene and ITS regions. Thebiomass productivity and lipid content of B. sudeticus J2 were 0.116 g L -¹ day -¹ and 40.1% of drywt., respectively. This was higher than the value of B. braunii UTEX 572, which is widely regardedas a superior strain among Botryococcus species. The relatively high growth rate of B. sudeticusJ2 was achieved under a light intensity of 240 μmol photons m -² s -¹ with ambient air spargingwhencompared to 120 μmol photons m -² s -¹ with 2% CO 2 supply. In summary, it is likely that the isolatedB. sudeticus J2 can be used for the mass cultivation and biodiesel production.