title: Improvement of Squalene Production from CO2in Synechococcus elongatus PCC 7942 by Metabolic Engineering and Scalable Production in a Photobioreactor.
abstract: The push-and-pull strategy for metabolic engineering was successfully demonstrated in Synechococcus elongatus PCC 7942, a model photosynthetic bacterium, to produce squalene from CO2. Squalene synthase (SQS) was fused to either a key enzyme (farnesyl diphosphate synthase) of the methylerythritol phosphate pathway or the β-subunit of phycocyanin (CpcB1). Engineered cyanobacteria with expression of a fusion CpcB1-SQS protein showed a squalene production level (7.16 ± 0.05 mg/L/OD730) that was increased by 1.8-fold compared to that of the control strain expressing SQS alone. To increase squalene production further, the gene dosage for CpcB1·SQS protein expression was increased and the fusion protein was expressed under a strong promoter, yielding 11.98 ± 0.49 mg/L/OD730of squalene, representing a 3.1-fold increase compared to the control. Subsequently, the best squalene producer was cultivated in a scalable photobioreactor (6 L) with light optimization, which produced 7.08 ± 0.5 mg/L/OD730squalene (equivalent to 79.2 mg per g dry cell weight). Further optimization for photobioprocessing and strain development will promote the construction of a solar-to-chemical platform.
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology , Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology , Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Wang
authors.forename: Ho Seok
authors.initials: HS
authors.lastname: Kwak
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology , Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology , Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
authors.forename: Youngsoon
authors.identifier: 0000-0003-1695-1874
authors.initials: Y
authors.lastname: Um
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology , Hwarangro 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
authors.forename: Yunje
authors.initials: Y
authors.lastname: Kim
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Sim
authors.affiliation: Department of Biotechnology and Bioengineering, Chonnam National University , 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of Korea.
authors.forename: Jong-Il
authors.initials: JI
authors.lastname: Choi
authors.affiliation: Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU) , 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
authors.forename: Han Min
authors.identifier: 0000-0002-8797-0477
authors.initials: HM
authors.lastname: Woo
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D058433:Photobioreactors / Q000382:microbiology; D015202:Protein Engineering / Q000379:methods; D013185:Squalene / Q000378:metabolism*; D046940:Synechococcus / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D013185:Squalene
keywords: CO2 conversion; Synechococcus elongatus PCC 7942; metabolic engineering; protein engineering; scalable production; squalene