Supporting Information
Supporting Text
T1 - Viability test after medium exchange. T. elongatus (wildtype Finland, wild-type
Japan) were grown in BG11 medium in Erlenmeyer flasks (batch cultures) containing
50mM D-fructose at 45°C under continuous light of 50 µEm-2s-1 for 7 days. In order to
test the viability of both bleached (with D-fructose) and non-bleached (control without
D-fructose) cells, the cell suspensions were harvested (3 min, 4500 g) and resuspended
in fresh BG11 medium without any D-fructose addition. The growth of these cultures,
under similar conditions as described above, was daily monitored by optical density
(OD750) and chlorophyll a measurements. A restart of proliferation (increase in OD750
and chlorophyll a content, respectively) and a regreening (chlorophyll a content) of
previously bleached cells was not been observed within 7 days under tested conditions.
T2 - Contamination and swelling check by microscopic and macroscopic findings.
T. elongatus (wildtype Finland, wild-type Japan) was grown in BG11 medium in
Erlenmeyer flasks (batch cultures) containing 50 mM D-fructose at 45°C under
continuous light of 50 µEm-2s-1 for 6 days. In order to test purity of the cultures as well
as potential swelling or shrinking effects due to D-fructose addition, all cell suspensions
were examined critically under the microscope (Zeiss Axiolab Fluorescence Microscope)
using phase contrast objectives and oil immersion. Neither contaminants (different in
size, shape, mobility and chlorophyll-a fluorescence activity) nor swelling and shrinking
effects have been observed (in comparison to control cultures without D-fructose).
Moreover, 80 µl of each cell suspension has been plated on LB agar and incubated at
45°C in the dark for three days. The contaminants will then be easily detected by their
superior growth, colour and different appearance. Not any visually different colonies
were detected under tested conditions.
T3 - Determination of apparent photosynthetic and respiratory rates. Cells of the
logarithmic growth phase were harvested, once washed and finally resuspended in fresh
BG11 medium, adjusting to a chlorophyll concentration of 15 µg ml-1 and incubated at
38°C in darkness (30 min). Light-saturated (1200 µEm-2s-1) steady-state rate of oxygen
evolution of different cell suspensions (as indicated) was measured using a Clark-type
platinum silver electrode in a thermostated glass cuvette (Hansatech Inc, England) in the
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presence of 15 mM sodium bicarbonate. The oxygen consumption rate was analogously
measured in the dark (10 min).
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Figure S1: D-fructose dose-dependent photomixotrophic growth properties of T.
elongatus BP-1 in batch cultures. Photographs of respective cultures at the 4th and 7th
day of D-fructose incubation illustrating biomass increase (top, 4th day) and bleaching
(bottom, 7th day) for different D-fructose concentrations (0, 5, and 50 mM). The batch
cultures were grown in BG11 medium in Erlenmeyer flasks at 48°C under continuous
shaking and continuous illumination with 50 µE m-2 s-1. The respective controls were
performed without the addition of D-fructose.
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Figure S2: Temporal changes in the pigment ratio of T. elongatus cells in the
presence of D-fructose. Representative whole cell absorption spectra of T. elongatus
grown at 45°C in BG11 under continuous illumination with 50 µEm-2s-1 in the absence
(A) and presence (B) of 50 mM D-fructose as a function of time (day 0 to day 6 after
inoculation). Whole cell absorbance spectra were daily recorded in the wavelength
range from 400 to 750 nm on a Specord50 spectrophotometer (Analytic Jena AG)
equipped with a scattering position and were normalized at 750 nm.
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Figure S3: Short-term heterotrophic growth properties of T. elongatus BP-1 in
batch cultures in the absence of light. Growth curve of T. elongatus BP-1 (one
biological replicate of wild-type WT from Finland, dark squares; one biological replicate
of wild-type WT from Japan, red rhomboids) in either complete darkness (solid line) or
under light-activated heterotrophic growth conditions (LAHG) (dashed line) in the
presence (filled symbols) or absence (open symbols) of 50 mM D-fructose. The batch
cultures were grown in BG11 medium in Erlenmeyer flasks at 48°C under continuous
shaking and diurnal short illumination (15 min) with 25 µE m -2 s-1 (LAHG). Complete
darkness has been achieved by shielding with aluminium foils. The respective controls
were performed without the additions of D-fructose (open symbols).
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Figure S4: Long-term growth properties of T. elongatus BP-1 on agar plates in the
presence of 50 mM D-fructose. (A) 150 microliters of concentrated pre-culture
suspension (wild-type WT from Finland, wild-type WT from Japan) with a similar cell
density were dropped on BG11 agar plates containing 50mM D-fructose. The plates
were incubated at 45°C for 20 days with diurnal short illumination (15 min) with 25 µE
m-2 s-1 (LAHG). The control plates did not contain any organic carbon source. (B)
Likewise, 150 microliters of concentrated pre-culture suspension (wild-type WT from
Finland, wild-type WT from Japan) with a similar cell density were dropped on BG11
agar plates containing 50mM D-fructose. The plates were incubated at 45°C for 24 days
with continuous white light of 50 µE m-2s-1. The control plates did not contain any
organic carbon source.
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Table S1: In vivo oxygen evolution and consumption rates of T. elongatus in the
presence of D-fructose. Cells of the early logarithmic growth phase were harvested,
once washed and finally resuspended in fresh BG11 medium containing 15 mM sodium
bicarbonate, adjusting to a chlorophyll a (Chl a) concentration of 15 µg ml-1 and preincubated at 38°C in darkness (30 min). Light-saturated (1200 µEm-2s-1) steady-state
rate of oxygen evolution of different cell suspensions, which were priorily grown in the
absence or presence of 50mM D-fructose in the light (50 µE m-2s-1), was measured using
a Clark-type electrode. The oxygen consumption rate was analogously measured in the
dark (10 min). The oxygen values represent data from two independent growth
experiments, each including both wild-type strains (Finland, Japan).
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