Takuya Sugawara1, Mariko Chinzei1, Setsuko Numano1, Chifumi Kitazaki1, Munehiko Asayama2,3,4. 1. Laboratory of Molecular Genetics, College of Agriculture, Ibaraki University, 3-21-1 Ami, Ibaraki, 300-0393, Japan. 2. Laboratory of Molecular Genetics, College of Agriculture, Ibaraki University, 3-21-1 Ami, Ibaraki, 300-0393, Japan. munehiko.asayama.777@vc.ibaraki.ac.jp. 3. Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho Kawaguchi, Saitama, 332-0012, Japan. munehiko.asayama.777@vc.ibaraki.ac.jp. 4. United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho Fuchu, Tokyo, 183-8509, Japan. munehiko.asayama.777@vc.ibaraki.ac.jp.
Abstract
OBJECTIVE: A novel filamentous cyanobacterium, a photosynthesizing microorganism, was isolated from a river, and its unique features of flocculation and pentadecane production were characterized. RESULTS: Microscopic observations and a phylogenetic analysis with 16S rDNA revealed that this strain was a Limnothrix species denoted as the SK1-2-1 strain. Auto cell-flocculation was observed when this strain was exposed to a two-step incubation involving a standing cultivation following a shaking preincubation. Flocculation was enhanced by blue light at a wavelength at 470 nm and irradiation for several hours to 1 day. Moreover, the strain exhibiting exponential cell growth may preferentially accumulate alkanes as pentadecane C15H32 alkane, which may be used as jet fuel, at a range of approximately 1% in the dry cell weight of flocculated cells. CONCLUSION: This is the first study on biofuel production using flocculated cells in which the specific manner of production may be regulated by cultivation conditions.
OBJECTIVE: A novel filamentous cyanobacterium, a photosynthesizing microorganism, was isolated from a river, and its unique features of flocculation and pentadecane production were characterized. RESULTS: Microscopic observations and a phylogenetic analysis with 16S rDNA revealed that this strain was a Limnothrix species denoted as the SK1-2-1 strain. Auto cell-flocculation was observed when this strain was exposed to a two-step incubation involving a standing cultivation following a shaking preincubation. Flocculation was enhanced by blue light at a wavelength at 470 nm and irradiation for several hours to 1 day. Moreover, the strain exhibiting exponential cell growth may preferentially accumulate alkanes as pentadecane C15H32 alkane, which may be used as jet fuel, at a range of approximately 1% in the dry cell weight of flocculated cells. CONCLUSION: This is the first study on biofuel production using flocculated cells in which the specific manner of production may be regulated by cultivation conditions.