title: Mild pressure induces rapid accumulation of neutral lipid (triacylglycerol) in Chlorella spp.
abstract: Effective enhancement of neutral lipid (especially triacylglycerol, TAG) content in microalgae is an important issue for commercialization of microalgal biorefineries. Pressure is a key physical factor affecting the morphological, physiological, and biochemical behaviors of organisms. In this paper, we report a new stress-based method for induction of TAG accumulation in microalgae (specifically, Chlorella sp. KR-1 and Ch. sp. AG20150) by very-short-duration application of mild pressure. Pressure treatments of 10-15bar for 2h resulted in a considerable, ∼55% improvement of the 10-100g/Lcells' TAG contents compared with the untreated control. The post-pressure-treatment increase of cytoplasmic TAG granules was further confirmed by transmission electron microscopy (TEM). Notwithstanding the increased TAG content, the total lipid content was not changed by pressurization, implying that pressure stress possibly induces rapid remodeling/transformation of algal lipids rather than de novo biosynthesis of TAG.
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea; Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere 33720, Finland.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Praveenkumar
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea; Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea.
authors.forename: Bohwa
authors.initials: B
authors.lastname: Kim
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea.
authors.forename: Jiye
authors.initials: J
authors.lastname: Lee
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea.
authors.forename: Durairaj
authors.initials: D
authors.lastname: Vijayan
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea; Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea.
authors.forename: Kyubock
authors.initials: K
authors.lastname: Lee
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea.
authors.forename: Bora
authors.initials: B
authors.lastname: Nam
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea.
authors.forename: Sang Goo
authors.initials: SG
authors.lastname: Jeon
authors.affiliation: Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea.
authors.forename: Dong-Myung
authors.initials: DM
authors.lastname: Kim
authors.affiliation: Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea. Electronic address: ykoh@kier.re.kr.
authors.forename: You-Kwan
authors.initials: YK
authors.lastname: Oh
mesh_terms: D002708:Chlorella / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D058086:Microalgae / Q000378:metabolism; D011312:Pressure; D013997:Time Factors; D014280:Triglycerides / Q000096:biosynthesis*
chemical_list: D014280:Triglycerides
keywords: Induction; Microalgae; Neutral lipid; Pressure stress; Triacylglycerol