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Hydrogen photoproduction by use of photosynthetic organisms and biomimetic systems
Allakhverdiev, Suleyman I.,Kreslavski, Vladimir D.,Thavasi, Velmurugan,Zharmukhamedov, Sergei K.,Klimov, Vyacheslav V.,Nagata, Toshi,Nishiharad, Hiroshi,Ramakrishna, Seeram Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.2
Hydrogen can be important clean fuel for future. Among different technologies for hydrogen production, oxygenic natural and artificial photosyntheses using direct photochemistry in synthetic complexes have a great potential to produce hydrogen, since both use clean and cheap sources: water and solar energy. Artificial photosynthesis is one way to produce hydrogen from water using sunlight by employing biomimetic complexes. However, splitting of water into protons and oxygen is energetically demanding and chemically difficult. In oxygenic photosynthetic microorganisms such as algae and cyanobacteria, water is split into electrons and protons, which during primary photosynthetic process are redirected by photosynthetic electron transport chain, and ferredoxin, to the hydrogen-producing enzymes hydrogenase or nitrogenase. By these enzymes, $e^-$ and $H^+$ recombine and form gaseous hydrogen. Biohydrogen activity of hydrogenase can be very high but it is extremely sensitive to photosynthetic $O_2$. In contrast, nitrogenase is insensitive to $O_2$, but has lower activity. At the moment, the efficiency of biohydrogen production is low. However, theoretical expectations suggest that the rates of photon conversion efficiency for $H_2$ bioproduction can be high enough (>10%). Our review examines the main pathways of $H_2$ photoproduction by using of photosynthetic organisms and biomimetic photosynthetic systems.
Photooxidation of alcohols by a porphyrin/quinone/TEMPO system
Nagasawa, Takayuki,Allakhverdiev, Suleyman I.,Kimura, Yoshifumi,Nagata, Toshi Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.2
Photooxidation of alcohols to the corresponding aldehydes with a porphyrin/quinone/TEMPO (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyloxy free radical) system is described. This photoreaction is a combination of a photoinduced electron transfer from the porphyrin to the quinone and a TEMPO-catalyzed oxidation of alcohols triggered by one electron oxidation. The rates of oxidation were in the order of benzylic $\approx$ allylic > primary $\gg$ secondary, which is consistent with the intermediacy of the oxoammonium cation derived from TEMPO. Examination of the initial rates suggested that the reaction proceeded via the triplet excited state of the zinc porphyrin. The dependence of initial rates on the oxidation potentials of the porphyrin showed a characteristic bell shape, which is caused by two competitive factors, the efficiency of photoinduced electron transfer and the equilibrium of electron exchange between the porphyrin cation radical and TEMPO. The potential significance of this reaction in photosynthetic model chemistry is briefly discussed.
Kurashov, Vasily N.,Allakhverdiev, Suleyman I.,Zharmukhamedov, Sergey K.,Nagata, Toshi,Klimov, Vyacheslav V.,Semenov, Alexey Yu.,Mamedov, Mahir D. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.2
An electrometric technique was used to investigate the generation of a photovoltage ($\Delta\psi$) by Mn-depleted spinach photosystem II (PS II) core particles incorporated into liposomes. In the presence of $MnCl_2$, the fast kinetically unresolvable phase of $\Delta\psi$ generation, related to electron transfer between the redox-active tyrosine $Y_Z$ and the primary plastoquinone acceptor $Q_A$ was followed by an additional electrogenic phase (${\tau}\;{\sim}\;20\;{\mu}s$, ~5% of the phase attributed to ${Y_Z}^{OX}{Q_A}^-$). The latter phase was ascribed to the transfer of an electron from the Mn, bound to the Mn-binding site of the PS II reaction center to the ${Y_Z}^{OX}$. An additional electrogenicity observed upon addition of synthetic trinuclear Mn complex-1 has a ${\tau}\;{\sim}\;50\;{\mu}s$ (~4% of the ${Y_Z}^{OX}Q_A$) and ${\tau}\;{\sim}\;160\;ms$ (~25%). The fast electrogenic component could be ascribed to reduction of ${Y_Z}^{OX}$ ox by Mn, delivered to the Mn-binding site in Mn-depleted samples after the release of the tripod ligands from the complex-1 while the slow electrogenic phase to the electron transfer from theMn-containing complex-1 attached to the protein-water boundary to the oxidized Mn at the protein-embedded Mn-binding site.
Carbon sequestrating fertilizers as a tool for carbon sequestration in agriculture under aridisols
Tahir Mukkram Ali,Hamza Ameer,Noor-us-Sabah,Hussain Sajad,Xie Zuoming,Brestic Marian,Rastogi Anshu,Allakhverdiev Suleyman I.,Sarwar Ghulam 한국탄소학회 2022 Carbon Letters Vol.32 No.7
Carbon is a part of all living creatures and it is the chief constructing block for life on this planet carbon occurs in several appearances, mainly as plant biomass, organic matter in soil, as gas CO2 in the air and dissipated in seawater. Soil carbon exhausts when production of carbon increases than carbon contribution. Soil comprises nearly 75% of total carbon existing on land, more than the quantity stockpiled in living animals and plants. So, soil plays a major part in maintaining a stable carbon cycle. Over the previous 150-year-period, the quantity of carbon present in the air has amplified by 30%. Majority of scientists thought that there is a straight relationship amongst amplified levels of CO2 in the air and increasing global warming. One anticipated technique to diminish atmospheric CO2 is to escalate the global packing of carbon in soils. Therefore, there is a necessity to manage soils because soil comprises more inorganic carbon as compared to the atmosphere and more organic carbon as compared to the biosphere. Soil is also thought to be a lively and important constituent in global carbon discharge and potential of sequestration. Carbon sequestration, known commonly as C-storage, can be acquired by different controlling practices, and the size of various management techniques, to enhance C-storage of soil and offer a key basin for atmospheric CO2, can be assessed most persuasively from studies conducted over long time that underwrite exclusive data on soil C accumulation, losses and storage. Sequestration happens when input of carbon enhances as compared to output of carbon. Soil carbon sequestration is the method of relocating CO2 from the air in to the soil with crop leftover and additional organic solids and in a configuration that is not instantly emitted back to the atmosphere. This review focused on beneficial role of carbon sequestrating fertilizers (press mud, boiler ash and compost) in carbon sequestration and soil properties.
Omar, S A,Elsheery, N I,Kalaji, H M,Ebrahim, M K H,Pietkiewicz, S,Lee, C-H,Allakhverdiev, S I,Xu, Zeng-Fu Consultants Bureau [etc.] 2013 Biochemistry Vol.78 No.5
<P>Plant dehydrin proteins (DHNs) are known to be important for environmental stress tolerance and are involved in various developmental processes. Two full-length cDNAs JcDHN-1 and JcDHN-2 encoding two dehydrins from Jatropha curcas seeds were identified and characterized. JcDHN-1 is 764 bp long and contains an open reading frame of 528 bp. The deduced JcDHN-1 protein has 175 a.a. residues that form a 19.3-kDa polypeptide with a predicted isoelectric point (pI) of 6.41. JcDHN-2 is 855 bp long and contains an open reading frame of 441 bp. The deduced JcDHN-2 protein has 156 a.a. residues that form a 17.1-kDa polypeptide with a predicted pI of 7.09. JcDHN-1 is classified as type Y3SK2 and JcDHN-2 is classified as type Y2SK2 according to the YSK shorthand for structural classification of dehydrins. Homology analysis indicates that both JcDHN-1 and JcDHN-2 share identity with DHNs of other plants. Analysis of the conserved domain revealed that JcDHN-2 has glycoside hydrolase GH20 super-family activity. Quantitative real time PCR analysis for JcDHN-1 and JcDHN-2 expression during seed development showed increasing gene expression of both their transcript levels along with the natural dehydration process during seed development. A sharp increase in JcDHN-2 transcript level occurred in response to water content dropping from 42% in mature seeds to 12% in dry seeds. These results indicate that both JcDHNs have the potential to play a role in cell protection during dehydration occurring naturally during jatropha orthodox seed development.</P>
Samar A. Omar,Nabil I. Elsheery,Hazem M. Kalaji,Zeng-Fu Xu,Song Song-Quan,Robert Carpentier,이춘환,Suleyman I. Allakhverdiev 한국식물학회 2013 Journal of Plant Biology Vol.56 No.4
Changes in H2O2 and the main antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR), in endospermic and embryonic tissues were studied in developing and artificially dried Jatropha curcas seeds. Immature seeds were desiccation-tolerant at 80 days after flowering, as they were able to germinate fully after artificial drying on silica gel had reduced their water content to 10–12% of fresh weight. In both endospermic and embryonic tissues, H2O2 level and, consequently, lipid peroxide content, decreased during seed development as well as after artificial dehydration of developing seeds. All examined antioxidant enzymes except DHAR showed a decrease in total activity in mature stages as compared with early stages. Expression analysis of SOD genes revealed that the decrease in total SOD activities was related to the decrease in Cu/Zn-SOD expression, while the continuous activity of SOD during maturation was related to an increase in Mn-SOD expression. Artificial drying resulted in increased SOD and DHAR activity, irrespective of the developmental stage. Our results revealed weak participation of CAT and APX in H2O2 scavenging, as well as no significant alterations in GR activities either during maturation or after artificial drying. Changes in SOD and GR isoenzyme patterns occurred during maturation-related drying, but not after artificial drying. These results highlight the role of ascorbate-glutathione cycle enzymes (DHAR and GR) in H2O2 scavenging during maturation or after artificial drying of developing J. curcas seeds.
Omar, Samar A.,Elsheery, Nabil I.,Kalaji, Hazem M.,Xu, Zeng-Fu,Song-Quan, Song,Carpentier, Robert,Lee, Choon-Hwan,Allakhverdiev, Suleyman I. 한국식물학회 2012 Journal of Plant Biology Vol.55 No.6
Changes in $H_2O_2$ and the main antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR), in endospermic and embryonic tissues were studied in developing and artificially dried Jatropha curcas seeds. Immature seeds were desiccation-tolerant at 80 days after flowering, as they were able to germinate fully after artificial drying on silica gel had reduced their water content to 10-12% of fresh weight. In both endospermic and embryonic tissues, $H_2O_2$ level and, consequently, lipid peroxide content, decreased during seed development as well as after artificial dehydration of developing seeds. All examined antioxidant enzymes except DHAR showed a decrease in total activity in mature stages as compared with early stages. Expression analysis of SOD genes revealed that the decrease in total SOD activities was related to the decrease in Cu/Zn-SOD expression, while the continuous activity of SOD during maturation was related to an increase in Mn-SOD expression. Artificial drying resulted in increased SOD and DHAR activity, irrespective of the developmental stage. Our results revealed weak participation of CAT and APX in $H_2O_2$ scavenging, as well as no significant alterations in GR activities either during maturation or after artificial drying. Changes in SOD and GR isoenzyme patterns occurred during maturation-related drying, but not after artificial drying. These results highlight the role of ascorbate-glutathione cycle enzymes (DHAR and GR) in $H_2O_2$ scavenging during maturation or after artificial drying of developing J. curcas seeds.
A new strategy to make an artificial enzyme: photosystem II around nanosized manganese oxide
Najafpour, Mohammad Mahdi,Madadkhani, Sepideh,Akbarian, Somayyeh,Hołyń,ska, Małgorzata,Kompany-Zareh, Mohsen,Tomo, Tatsuya,Singh, Jitendra Pal,Chae, Keun Hwa,Allakhverdiev, Suleyman I. The Royal Society of Chemistry 2017 Catalysis Science & Technology Vol.7 No.19
<▼1><P>A new strategy to make an artificial enzyme was reported.</P></▼1><▼2><P>Herein we report a new strategy to disperse Mn oxide into the apoenzyme of photosystem II. The compound was characterized by scanning electron microscopy, transmission electron microscopy, UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray absorption near edge structure, extended X-ray absorption fine structure, X-ray diffraction and some electrochemical methods. Under electrochemical conditions, the peaks attributed to Mn(ii)/(iii), Mn(iii)/(iv) and Mn(ii)/(iv) were assigned and compared with other manganese oxides. Linear sweep voltammetry shows that water electro-oxidation occurs at 80 mV less than that for the apoenzyme of photosystem II. Thus, Mn oxide maintains its water-oxidizing activity under these conditions. The compound is a new type of structural and functional model for the water-oxidizing complex in photosystem II.</P></▼2>
Biological water-oxidizing complex: a nano-sized manganese-calcium oxide in a protein environment.
Najafpour, Mohammad Mahdi,Moghaddam, Atefeh Nemati,Yang, Young Nam,Aro, Eva-Mari,Carpentier, Robert,Eaton-Rye, Julian J,Lee, Choon-Hwan,Allakhverdiev, Suleyman I W. Junk ; Kluwer Academic Publishers 2012 Photosynthesis research Vol.114 No.1
<P>The resolution of Photosystem II (PS II) crystals has been improved using isolated PS II from the thermophilic cyanobacterium Thermosynechococcus vulcanus. The new 1.9 resolution data have provided detailed information on the structure of the water-oxidizing complex (Umena et al. Nature 473: 55-61, 2011). The atomic level structure of the manganese-calcium cluster is important for understanding the mechanism of water oxidation and to design an efficient catalyst for water oxidation in artificial photosynthetic systems. Here, we have briefly reviewed our knowledge of the structure and function of the cluster.</P>