title: LED light stress induced biomass and fatty acid production in microalgal biosystem, Acutodesmus obliquus.
abstract: Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell.
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Yong-Keun
authors: YK
authors: Choi
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea. Electronic address: kumaran.ran@gmail.com.
authors: Rangarajulu Senthil
authors: RS
authors: Kumaran
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Hyeon Jin
authors: HJ
authors: Jeon
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Hak-Jin
authors: HJ
authors: Song
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Yung-Hun
authors: YH
authors: Yang
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Sang Hyun
authors: SH
authors: Lee
authors: Water Environment Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang-Gu, Seoul 130-650, Republic of Korea.
authors: Kyung-Guen
authors: KG
authors: Song
authors: Urban Agriculture Research Division, National Institute of Horticultural and Herbal Science, Rural Development Administration, Suwon 441-440, Republic of Korea.
authors: Kwang Jin
authors: KJ
authors: Kim
authors: Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Vijay
authors: V
authors: Singh
authors: Department of Biological Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-Gu, Seoul 143-701, Republic of Korea.
authors: Hyung Joo
authors: HJ
authors: Kim
mesh_terms: D018533:Biomass; D002478:Cells, Cultured; D004581:Electronics; D005227:Fatty Acids / Q000096:biosynthesis*; D008027:Light; D066292:Lipid Droplets / Q000378:metabolism; D058086:Microalgae / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D013312:Stress, Physiological / Q000528:radiation effects*; D013997:Time Factors
chemical_list: D005227:Fatty Acids
keywords: Acutodesmus obliquus; Fatty acid; Flashing light; Light stress; Microalgal biosystem; Optimal timing