1 research outputs found
Stimulation of Hydrogen Photoproduction in Chlorella sorokiniana Subjected to Simultaneous Nitrogen Limitation and Sulfur- and/or Phosphorus-Deprivation
Photosynthetic hydrogen (H2
) production by green algae has fascinated biologists and energy experts, due to the
potential application of this process for renewable energy. In this study, H2
photoproduction and PSII photochemical
activities were investigated in Chlorella sorokiniana exposed to simultaneous nitrogen limitation and sulfur (S-) and/
or phosphorus (P-) deprivation. Under S-deprivation, C. sorokiniana produced about 48.2 mL L-1 of H2
. Moreover,
simultaneous nitrogen limitation (0.7 mM NH4
Cl) and sulfur- and/or phosphorus-deprivation significantly increased
H2
production of C. sorokiniana over that of S-deprivation alone. Maximum H2
outputs of 77.3, 98.1 and 125.1 mL L-1
were obtained in the N-limited cultures exposed to P-deprivation (TAP-P), S-deprivation (TAP-S) and simultaneous
S- and P-deprivation (TAP-S-P), respectively. The average rate of H2
production for the N-limited culture exposed
to TAP-P, TAP-S and TAP-S-P was 1.07, 1.36 and 1.50 mL L-1 h-1, respectively. Interestingly, the H2
inducement time
in the culture subjected to simultaneous N-limitation and S- and/or P-deprivation was much shorter than that of
traditional S-deprivation. The photosynthetic inhibitors, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and
2,5-dibromo-3-methyl-6-isopropylp-benzoquinone (DBMIB) repressed H2 production in TAP-S-P (0.7 mM NH4
Cl)
medium by 68.04% and 98.65%, respectively. The conditions of simultaneous N-limitation, S- and P-deprivation
provided another efficient method for inducing H2
production in C. sorokiniana. In addition, we also found that
two-thirds of the required electrons were generated from the splitting of H2
O in PSII and that the remaining onethird possibly came from some other substrate catabolism