Main Article Content
Green microalgae can use solar energy and water to produce H2 via hydrogenase enzyme activity. The unicellular green alga Chlorella sp. LSD-W2 has been previously shown to produce high H2 under nitrogen deprivation. This research aimed to examine the effects of light intensity and light pattern on H2 production by Chlorella sp. LSD-W2 under nitrogen deprivation. The result showed that H2 production rate was significantly enhanced when light intensities were increased. The cells could hardly produce H2 in the dark. The highest H2 production rate with 0.956 ± 0.015 mL L-1 h-1 was obtained in cells incubated in TAP-N medium in a 120-mL glass bottle under light intensity of 60 µmol photons m-2 s-1. H2 production by cells incubated under light/dark or dark/light cycles was lower than that under continuous light illumination. In order to reduce O2 which is an inhibitor of hydrogenase enzyme, the PSII inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was added to the Chlorella sp. LSD-W2 cell cultures. It was found that O2 was obviously decreased in cells treated with 10 µM DCMU. Unexpectedly, DCMU caused the reduction of H2 production by Chlorella sp. LSD-W2.
 Perry JH. Chemical engineers’ handbook. McGraw-Hill: New York; 1963.
 Gfeller RP, Gibbs M. Fermentative metabolism of Chlamydomonas reinhardtii I. Analysis of fermentative products from starch in dark and light. Plant Physiol. 1984;75:212-218.
 Melis A, Happe T. Hydrogen production. Green algae as a source of energy. Plant Physiol. 2001;127:740-748.
 Happe T, Kaminski A. Differential regulation of the Fe-hydrogenase during anaerobic adaptation in the green alga Chlamydomonas reinhardtii. Eur J Biochem. 2002;269:1022-1032.
 Forestier M, King P, Zhang L, Posewitz M, Schwarzer S, Happe T, Ghirardi ML, Seibert M. Expression of two [Fe]-hydrogenases in Chlamydomonas reinhardtii under anaerobic conditions. Eur J Biochem. 2003;270:2750-2758.
 Melis A, Zhang L, Forestier M, Ghirardi ML, Seibert M. Sustained photobiological hydrogen gas production upon reversible inactivation of oxygen evolution in the green alga Chlamydomonas reinhardtii. Plant Physiol. 2000;122:127-136.
 Stripp ST, Goldet G, Brandmayr C, Sanganas O, Vincent KA, Haumann M, Armstrong FA, Happe T. How oxygen attacks [FeFe] hydrogenases from photosynthetic organisms. Proc Natl Acad Sci USA. 2009;106:17331-17336.
 Tinpranee N, Incharoensakdi A, Phunpruch S. Hydrogen production by unicellular green alga Chlorella sp. LSD-W2 isolated from seawater in Thailand. Asia Pac J Sci Technol. 2016;22(1):256-266.
 Puangplub A, Incharoensakdi A, Phunpruch S. Screening of green algae isolated from natural water sources in Thailand for H2 production. The Proceeding of 55th Kasetsart University Annual Conference; 2017 Jan 31-Feb 3; Bangkok, Thailand; 2017.p.199-206.
 Laurinavichene T, Tolstygina I, Tsygankov A. The effect of light intensity on hydrogen production by sulfur-deprived Chlamydomonas reinhardtii. J Biotechnol. 2004;114: 143-151.
 Kim JP, Kang CD, Park TY, Kim MS, Sim SJ. Enhanced hydrogen production by controlling light intensity in sulfur deprived Chlamydomonas reinhardtii culture. Int J Hydrogen Energy. 2006;31:1585-1590.
 Oncel S, Vardar Sukan F. Effect of light intensity and the light: dark cycles on the long term hydrogen production of Chlamydomonas reinhardtii by batch cultures. Biomass Bioenerg. 2011;35:1066-1074.
 Rashid N, Lee K, Mahmood Q. Bio-hydrogen production by Chlorella vulgaris under diverse photoperiods. Bioresour Technol. 2011;102:2101-2104.
 Wang H, Fan X, Zhang Y, Yang D, Guo R. Sustained photo-hydrogen production by Chlorella pyrenoidosa without sulfur depletion. Biotechnol Lett. 2011;33:1345-1350.
 Gabrielyan, L, Hakobyan, L, Trchounian, A. Characterization of light-dependent hydrogen production by new green microalga Parachlorella kessleri in various conditions. J Photochem Photobiol B. 2017;175: 207-210.
 Antal TK, Krendeleva TE, Rubin AB. Acclimation of green algae to sulfur deficiency: underlying mechanisms and application for hydrogen production. Appl Microbiol Biot. 2011;89:3-15.
 Hemschemeier A, Fouchard S, Cournac L, Peltier G, Happe T. Hydrogen production by Chlamydomonas reinhardtii: an elaborate interplay of electron sources and sink. Planta. 2008;227:397-407.
 Fouchard S, Hemschemeier A, Caruana A, Pruvost J, Legrand J, Happe T, Peltier G, Cournac L. Autotrophic and mixotrophic hydrogen photoproduction in sulfur-deprived Chlamydomonas cells. Appl Environ Microb. 2005;71:6199-6205.
 Liu JZ, Ge YM, Xia SY, Sun JY, Mu J. Photoautotrophic by Chlorella pyrenoidosa without sulfur-deprivation. Int J Hydrogen Energy. 2016;41:8427-8432.
 Zhang L, He M, Liu J. The enhancement mechanism of hydrogen photoproduction in Chlorella protothecoides under nitrogen limitation and sulfur deprivation. Int J Hydrogen Energy. 2014;39:8969-8976.
 Pongpadung P, Zhang L, Sathasivam R, Yokthongwattana K, Juntawong N, Liu J. Stimulation of Hydrogen Photoproduction in Chlorella sorokiniana Subjected to Simultaneous Nitrogen Limitation and Sulfur-and/or Phosphorus-Deprivation. J Pure Appl Microbiol. 2018;12(4):1719-1727.
 Harris EH, The Chlamydomonas sourcebook: a comprehensive guide to biology and laboratory use. San Diego: Academic Press; 1989.
 Taikhao S, Junyapoon S, Incharoensakdi A, Phunpruch S. Factors affecting biohydrogen production by unicellular halotolerant cyanobacterium Aphanothece halophytica. J Appl Phycol. 2013;25:575-585.
 Ji CF, Yu XJ, Chen ZA, Xue S, Legrand J, Zhang W. Effects of nutrient deprivation on biochemical compositions and photo-hydrogen production of Tetraselmis subcordiformis. Int J Hydrogen Energy. 2011;36(10):5817-5821.
 Chochois V, Dauvillee D, Beyly A, Tolleter D, Cuine S, Timpano H, Ball S, Cournac L, Peltier G. Hydrogen production in Chlamydomonas: photosystem II-dependent and -independent pathways differ in their requirement for starch metabolism. Plant Physiol. 2009;151:631-640.
 Kosourov S, Tsygankov A, Seibert M, Ghirardi ML. Sustained hydrogen photoproduction by Chlamydomonas reinhardtii: effects of culture parameters. Biotechnol Bioeng. 2002;78:731-740.
 Mus F, Cournac L, Cardettini V, Caruana A, Peltier G. Inhibitor studies on non-photochemical plastoquinone reduction and H2 photoproduction in Chlamydomonas reinhardtii. Biochim Biophys Acta. 2005;1708(3):322-332.
 Noth J, Krawietz D, Hemschemeier A, Happe T. Pyruvate : ferredoxin oxidoreductase is coupled to light-independent hydrogen production in Chlamydomonas reinhardtii. J Biol Chem. 2013;288:4368-4377.
 Antal TK, Volgusheva AA, Kukarskih GP, Krendeleva TE, Rubin AB. Relationships between H2 production and different electron transport pathways in sulfur-deprived Chlamydomonas reinhardtii. Int J Hydrogen Energy. 2009;34:9087-9094.
 Li T, Zheng Y, Yu L, Chen S. Mixotrophic cultivation of a Chlorella sorokiniana strain for enhanced biomass and lipid production. Biomass Bioenerg. 2014;66:204-213.