TY - JOUR
T1 - Probing the effects of high-light stress on pigment and lipid metabolism in nitrogen-starving microalgae by measuring chlorophyll fluorescence transients
T2 - Studies with a δ5 desaturase mutant of Parietochloris incisa (Chlorophyta, Trebouxiophyceae)
AU - Solovchenko, Alexei
AU - Solovchenko, Olga
AU - Khozin-Goldberg, Inna
AU - Didi-Cohen, Shoshana
AU - Pal, Dipasmita
AU - Cohen, Zvi
AU - Boussiba, Sammy
N1 - Funding Information:
This work was in part funded by the Ministry of Science and Education of Russian Federation ‘Skolkovo’ Scientific Fund , and PTT Global Chemical Public Company Limited (Thailand) . Financial support by the European Commission's Seventh Framework Programme for Research and Technology Development (FP7) , project SENSBIOSYN, Grant Nr. 232522 , is gratefully acknowledged.
PY - 2013/7/1
Y1 - 2013/7/1
N2 - We investigated effects of irradiance on the relationships between chlorophyll fluorescence transients (OJIP), carotenoid-to-chlorophyll ratio, and fatty acids in a nitrogen-deprived Parietochloris incisa (Chlorophyta, Trebouxiophyceae) δ5 desaturase mutant accumulating valuable LC-PUFA dihomo-γ-linolenic acid (DGLA). High light (270μE·m-2·s-1 PAR) and nitrogen starvation brought about a decrease in maximum quantum yield of photosystem II (ΦP0) and electron transport (ΦE0) but enhanced the quantum yield of thermal dissipation (ΦD0) and induced non-photochemical quenching (NPQ) in an irradiance-dependent manner. Under high irradiance a decline in the rate of total fatty acid accumulation and DGLA percentage in comparison with the cultures grown under 130μE·m-2·s-1 PAR was recorded. Increasing irradiance from 130 to 270μE·m-2·s-1 enhanced total fatty acid accumulation only within the first week of nitrogen starvation and negatively affected DGLA production. Regardless of irradiance, ΦP0, ΦE0, and ΦD0 exhibited tight (r2=0.8-0.9) relationships with the stress-induced changes of total fatty acid and DGLA content and the carotenoid-to-chlorophyll ratio. The applicability and limitations of OJIP and its derived parameters for on-line monitoring of physiological condition and accumulation of value-added products in microalgal cultures grown in photobioreactors are discussed.
AB - We investigated effects of irradiance on the relationships between chlorophyll fluorescence transients (OJIP), carotenoid-to-chlorophyll ratio, and fatty acids in a nitrogen-deprived Parietochloris incisa (Chlorophyta, Trebouxiophyceae) δ5 desaturase mutant accumulating valuable LC-PUFA dihomo-γ-linolenic acid (DGLA). High light (270μE·m-2·s-1 PAR) and nitrogen starvation brought about a decrease in maximum quantum yield of photosystem II (ΦP0) and electron transport (ΦE0) but enhanced the quantum yield of thermal dissipation (ΦD0) and induced non-photochemical quenching (NPQ) in an irradiance-dependent manner. Under high irradiance a decline in the rate of total fatty acid accumulation and DGLA percentage in comparison with the cultures grown under 130μE·m-2·s-1 PAR was recorded. Increasing irradiance from 130 to 270μE·m-2·s-1 enhanced total fatty acid accumulation only within the first week of nitrogen starvation and negatively affected DGLA production. Regardless of irradiance, ΦP0, ΦE0, and ΦD0 exhibited tight (r2=0.8-0.9) relationships with the stress-induced changes of total fatty acid and DGLA content and the carotenoid-to-chlorophyll ratio. The applicability and limitations of OJIP and its derived parameters for on-line monitoring of physiological condition and accumulation of value-added products in microalgal cultures grown in photobioreactors are discussed.
KW - Chlorophyll fluorescence transient
KW - Dihomo-γ-linolenic acid
KW - Nitrogen deficiency
KW - OJIP
KW - On-line monitoring
KW - Parietochloris incisa
UR - http://www.scopus.com/inward/record.url?scp=84879260461&partnerID=8YFLogxK
U2 - 10.1016/j.algal.2013.01.010
DO - 10.1016/j.algal.2013.01.010
M3 - Article
AN - SCOPUS:84879260461
SN - 2211-9264
VL - 2
SP - 175
EP - 182
JO - Algal Research
JF - Algal Research
IS - 3
ER -