TY - JOUR
T1 - Thermorecovery of cyanobacterial fatty acids at elevated temperatures
AU - Liu, Xinyao
AU - Curtiss, Roy
N1 - Funding Information:
This work was supported by Arizona State University Startup Funding to RCIII and US Department of Energy ARPA-E grant ( DE-AR0000011 ). The authors thank Rebecca Allen, Erika Arch, Sarah Fallon, Michael Fisher, Greg Golden, Yingqin Luo, Sebastian Romero, Javier Santander, Soo-Young Wanda and Stanly Williams for help and advice on this work.
PY - 2012/11/15
Y1 - 2012/11/15
N2 - We have developed a genetic system we call " thermorecovery" that allows us to lyse cyanobacterial cultures and hydrolyze membrane lipids to release free fatty acids (FFAs), a biofuel precursor. The system uses thermostable lipases encoded by genes from thermophilic organisms that have been transferred into the cyanobacterial genome and can be synthesized by turning off CO2 availability and subsequently activated by increasing the concentrated culture temperature. When synthesized in FFA-producing strains, the lipase Fnl from Fervidobacterium nodosum Rt17-B1 released the most FFA. Of the seven candidate lipases investigated, Fnl-synthesizing strains yielded 42.7±1.5mg/l FFA at 47°C. We also determined that the optimal production conditions for SD338, the Synechocystis strain synthesizing Fnl, was to keep the cell concentrates at 46°C for two days after a one-day CO2 limitation pretreatment of the culture. A 4-l continuous semi-batch production experiment with SD338 showed that daily harvested cultures (1l) released an average of 43.9±6.6mg fatty acid and this productivity lasted for at least 20 days without significant decline. This improved thermorecovery process can be used in conjunction with other means to genetically engineer cyanobacteria to produce biofuels or biofuel precursors as the final step in recovery of membrane lipids.
AB - We have developed a genetic system we call " thermorecovery" that allows us to lyse cyanobacterial cultures and hydrolyze membrane lipids to release free fatty acids (FFAs), a biofuel precursor. The system uses thermostable lipases encoded by genes from thermophilic organisms that have been transferred into the cyanobacterial genome and can be synthesized by turning off CO2 availability and subsequently activated by increasing the concentrated culture temperature. When synthesized in FFA-producing strains, the lipase Fnl from Fervidobacterium nodosum Rt17-B1 released the most FFA. Of the seven candidate lipases investigated, Fnl-synthesizing strains yielded 42.7±1.5mg/l FFA at 47°C. We also determined that the optimal production conditions for SD338, the Synechocystis strain synthesizing Fnl, was to keep the cell concentrates at 46°C for two days after a one-day CO2 limitation pretreatment of the culture. A 4-l continuous semi-batch production experiment with SD338 showed that daily harvested cultures (1l) released an average of 43.9±6.6mg fatty acid and this productivity lasted for at least 20 days without significant decline. This improved thermorecovery process can be used in conjunction with other means to genetically engineer cyanobacteria to produce biofuels or biofuel precursors as the final step in recovery of membrane lipids.
KW - Biofuel
KW - Cyanobacteria
KW - Fatty acid
KW - Thermostable lipases
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U2 - 10.1016/j.jbiotec.2012.08.013
DO - 10.1016/j.jbiotec.2012.08.013
M3 - Article
C2 - 22944207
AN - SCOPUS:84866767895
SN - 0168-1656
VL - 161
SP - 445
EP - 449
JO - Journal of Biotechnology
JF - Journal of Biotechnology
IS - 4
ER -