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Item type:Publication, Photobiohydrogen Production and Strategies for H2 Yield Improvements in Cyanobacteria(2023-01-01) ;Khetkorn, Wanthanee ;Raksajit, Wuttinun ;Maneeruttanarungroj, CherdsakLindblad, PeterHydrogen gas (H<inf>2</inf>) is one of the potential future sustainable and clean energy carriers that may substitute the use of fossil resources including fuels since it has a high energy content (heating value of 141.65 MJ/kg) when compared to traditional hydrocarbon fuels [1]. Water is a primary product of combustion being a most significant advantage of H<inf>2</inf> being environmentally friendly with the capacity to reduce global greenhouse gas emissions. H<inf>2</inf> is used in various applications. It generates electricity in fuel cells, including applications in transportation, and can be applied as fuel in rocket engines [2]. Moreover, H<inf>2</inf> is an important gas and raw material in many industrial applications. However, the high cost of the H<inf>2</inf> production processes requiring the use of other energy sources is a significant disadvantage. At present, H<inf>2</inf> can be prepared in many conventional ways, such as steam reforming, electrolysis, and biohydrogen production processes. Steam reforming uses high-temperature steam to produce hydrogen gas from fossil resources including natural gas. Electrolysis is an electrolytic process to decompose water molecules into O<inf>2</inf> and H<inf>2</inf>. However, both these two methods are energy-intensive and producing hydrogen from natural gas, which is mostly methane (CH<inf>4</inf>) and in steam reforming generates CO<inf>2</inf> and pollutants as by-products. On the other hand, biological hydrogen production is more environmentally sustainable and less energy intensive than thermochemical and electrochemical processes [3], but most concepts are not yet developed to production scale. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Improved biohydrogen production by immobilized cells of the green alga Tetraspora sp. CU2551 incubated under aerobic condition(2020-10-01) ;Maswanna, Thanaporn ;Lindblad, PeterManeeruttanarungroj, CherdsakThe green alga Tetraspora sp. CU2551 was previously investigated and showed enhanced H<inf>2</inf> production under anaerobic (Ar purged) conditions by cells immobilized in a calcium alginate matrix (Maswanna et al., Biomass Bioenergy 111:88–95, 2018). Here, we report successful H<inf>2</inf> production in entrapped cells under aerobic conditions. The most favorable immobilization condition observed was 4% (w/v) final alginate concentration after gelation, 2.80- to 3.35-mm beads, and a biomass content of 0.125 mg DW mL<sup>−1</sup> alginate. H<inf>2</inf> production increased when the immobilized cells were incubated in S-deprived media which could be repeated up to six times when using refreshed media. After six cycles, the H<inf>2</inf> production reached 12.8 ± 0.9 mL H<inf>2</inf> 25 mL<sup>−1</sup> of medium, corresponding to a rate of 182 ± 20 nmol mg<sup>−1</sup> DW h<sup>−1</sup>, which was significantly higher than previously observed for other microalgae. Thus, our results demonstrate a potential for photobiological H<inf>2</inf> production using immobilized Tetraspora sp. CU2551 cells, grown under ambient aerobic conditions. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced hydrogen production by optimization of immobilized cells of the green alga Tetraspora sp. CU2551 grown under anaerobic condition(2018-04-01) ;Maswanna, Thanaporn ;Phunpruch, Saranya ;Lindblad, PeterManeeruttanarungroj, CherdsakThe green alga Tetraspora sp. CU2551 has previously been identified and characterized as a photosynthetic microorganism with high potential for H<inf>2</inf> production. In the present study, cells of Tetraspora CU2551 were entrapped and immobilized in an alginate matrix with the aim to analyze the effect of cell stacking and a reduced exposure of O<inf>2</inf> to the cells. The results showed that the most favorable immobilization conditions were 4% (w/v) of final alginate concentration and a cell concentration of 0.125 mg cell dry wt/mL alginate with a bead diameter of 2.80–3.35 mm. The H<inf>2</inf> production yields increased when the immobilized cells were incubated in S-deprived medium and this could be repeated at least for 3 production times. Maximal total H<inf>2</inf> production reached 7.68 ± 0.88 mL H<inf>2</inf>/25 mL medium, corresponding to a rate of 1182.45 ± 24.40 nmol H<inf>2</inf>/h/mg DW. This production is about 6 times higher compared to by cells in suspension, 2–10 times higher when compared to by other green algae, and 10–50 times higher when comparing with cyanobacteria. Based on our observations, immobilized cells of Tetraspora CU2551 is considered a very promising biological system for significant photobiological H<inf>2</inf> production by a photosynthetic microorganism.
