초록
<P><B>Graphical abstract</B></P><P><ce:figure id='f0025'></ce:figure></P><P><B>Highlights</B></P><P>► Temperature shifts significantly affected the lipid production rate of <I>Synechocystis</I>. ► Exposure to 44°C, 22°C, and 18°C severely inhibited lipid production. ► Temperature shifts also triggered major variations in individual fatty acids in the lipids. ► The degree of unsaturation changed from 0.87 at 30°C, to 0.62 at 44°C, and to 1.29 at 18°C. ► Prolonged exposure of <I>Synechocystis</I> to extreme temperatures must be avoided if biofuel production is the goal.</P> <P><B>Abstract</B></P><P><I>Synechocystis</I> sp. PCC6803 exhibited a high degree of variation in biomass and lipid production rates in response to temperature changes in a photobioreactor. Compared with an optimal temperature of 30–33°C, a higher temperature of 44°C and lower temperatures of 22°C and 18°C severely inhibited the specific growth rate (up to a 66% decrease), biomass production rate (up to a 71% decrease), nutrient utilization rates (up to a 77% decrease), and lipid production rate (up to a 80% decrease). Temperature stress triggered changes in the relative percentage of individual fatty acids (mainly for C16:0 and C18:3), and degree of unsaturation significantly changed: 0.87 at 30°C, 0.62 at 44°C, and 1.29 at 18°C. Although PCC6803 survived temperature stress and maintained its predominate position in the culture, it could not fully recover from long-term temperature stress. Thus, avoiding prolonged exposure to extreme temperature is crucial for using PCC6803 as feedstock for biofuel production.</P>