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Improvement of biohydrogen production from biomass using supercritical water gasification and CaO adsorption
(2024-04-01)
Panichkittikul, Nitsara
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Mariyappan, Vinitha
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Wu, Wei
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Patcharavorachot, Yaneeporn
Producing biohydrogen is a promising alternative to fossil fuels, sourced from renewable energy like wind, solar, and biomass, known for its eco-friendliness and minimal greenhouse gas emissions. This study focuses on the process design and simulation of producing biohydrogen from biomass (bagasse) gasification. New integration of the water gas shift reactor and CaO adsorption process is connected to biomass gasification with the steam/supercritical water agents for improving the hydrogen production process. Simulations show that steam gasification integrated with CaO adsorption (SG-CaO) is optimized at specific conditions, resulting in high-purity hydrogen at 99.95 %. Similarly, the supercritical water gasification integrated with CaO adsorption (SCWG-CaO) requires specific conditions, achieving exceptionally pure hydrogen at 99.99 %. In terms of energy analysis, SCWG-CaO outperforms SG-CaO, with higher hydrogen yield (14.16 % vs. 14.12 %) and greater energy efficiency (42.32 % vs. 40.26 %). It shows that the SCWG-CaO is a suitable and efficient approach for biohydrogen production, considering factors such as hydrogen purity, yield, and energy efficiency.
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Optimal conditions for maximized H2 yield from a new green algal strain Chlorella sp. KLSc61
(2022-08-01)
Laokua, Natwikar
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Rittiyan, Nutnicha
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Kornrawudaphikasama, Yosita
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Klinsalee, Rachaneekorn
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Tonawut, Yothawut
Hydrogen produced from microalgae is attracting the attention of scientists as a potential new ‘Bio-Circular-Green’ energy source. We screened a selection of naturally occurring algal strains for H<inf>2</inf> yield as a basis for high yield development. The best strain was a new strain of biohydrogen-producing green algae from a fresh water source at King Mongkut's Institute of Technology Ladkrabang, Thailand. Using morphological and 18S rDNA sequencing analyses, this alga was identified and classified as Chlorella sp. KLSc61. When adapted cells in TAP-K medium (with starting pH at 9.0) containing 25 mM ethanol, with 54 μmol photons m−2 s−1 light, and incubated at 35 °C, Chlorella sp. KLSc61 showed a maximum H<inf>2</inf> yield of 9,804 ± 469.5 μmol H<inf>2</inf> mg−1 Chl at day 7. Under these conditions, the cells produced ~ 12.2 times more H<inf>2</inf> gas than without optimization (753.0 μmol H<inf>2</inf> mg−1Chl). Our optimized system also produced H<inf>2</inf> at a rate 11–570 times greater than previously reported microalgae. Thus Chlorella sp. KLSc61 could be a viable strain for biohydrogen production as a clean future energy source.
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Response of green alga Tetraspora sp. CU2551 under potassium deprivation: a new promising strategy for hydrogen production
(2022-04-01)
Pewnual, Totsapon
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Jampapetch, Narirat
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Saladtook, Sathonkorn
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Raksajit, Wuttinun
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Klinsalee, Rachaneekorn
With increasing world energy consumption, renewable energy sources can fulfill the need and many have net zero carbon dioxide emissions. One of these is hydrogen, which is biologically produced molecular hydrogen from organisms. Although many studies have produced hydrogen from green algae and optimized conditions to obtain the highest yield, following our previous works on production optimization from Tetraspora sp. CU2551, we tested deprivation of Fe, Cu, Ca, S, Mg, or K, and surprisingly found that K deprivation showed another promising switch in increased H<inf>2</inf> yield, representing 9.2 ± 0.1 μmol mg−1 DW within 32 h incubation anaerobically. Moreover, longer cell adaptation by aerobic incubation, before production phase, resulted in higher hydrogen yield. Cells adapted in potassium deprivation (TAP-K medium) promoted hydrogen production to a yield of 14.8 ± 0.03 μmol mg−1 DW, or about 3.0 times higher than normal TAP (5.0 ± 0.82 μmol mg−1 DW). The increased yield was caused by (1) lowering PSII activity (direct biophotolysis), resulted in less oxygen being produced, lowering hydrogenase inhibitor levels, and (2) increasing accumulated starch degradation (indirect biophotolysis) (12.2% starch remaining or 7.2 ± 0.9 μg mg−1 DW), increased the flow of electrons to hydrogenase. Our finding makes potassium deprivation conditions as another the promising choice to enhance hydrogen production in biological systems.
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Biomass and biohydrogen production by unicellular green alga Chlorella vulgaris var. vulgaris TISTR 8261 using frozen food industrial wastewater
(2022-01-01)
Taikhao, Samart
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Phunpruch, Saranya
Biohydrogen production by green algal biomass is promising method for sustainable H<inf>2</inf> production and bioenergy recovery. In this approach, green algae convert organic and inorganic substances (used as the sole source of carbon and electrons) in wastewater into H<inf>2</inf>. In this study, biomass and H<inf>2</inf> production from the unicellular green alga Chlorella vulgaris var. vulgaris TISTR 8261, cultivated in frozen food industrial wastewater, was investigated. The results revealed that growth rate of algal cells cultivated in treated wastewater was significantly higher than that in untreated wastewater but lower than that in the synthetic control Tris acetate phosphate (TAP) medium. In addition, the cells grown in treated wastewater exhibited a high ability to remove nitrate, nitrite, phosphate, and sulfate from the water. Furthermore, algal cells were cultured with various concentrations of sodium acetate (0-17.4 mM); the optical density of the cultures at 750 nm increased with increase in acetate concentration. Cell growth in treated wastewater supplemented with 17.4 mM sodium acetate was similar to that in TAP medium. The highest H<inf>2</inf> production of 12.87 ± 0.58 µmolH<inf>2</inf> mg Chl a-1 was observed in cells incubated in treated wastewater supplemented with 17.4 mM sodium acetate; this yield was higher than that obtained from cells incubated in nitrogen-free TAP medium. The results of this study support the potential use of wastewater for biomass and biohydrogen production by C. vulgaris var. vulgaris TISTR 8261.
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A newly isolated green alga Chlorella sp. KLSc59: potential for biohydrogen production
(2020-10-01)
Sirawattanamongkol, Thanaporn
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Maswanna, Thanaporn
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Maneeruttanarungroj, Cherdsak
Hydrogen production from microalgae has attracted considerable attention due to its high energy content and as a renewable and environmentally friendly energy source. Various strains of microalgae have been reported to produce “biohydrogen”, but screening for new strains is still necessary to discover strains with higher hydrogen yields. A newly isolated hydrogen-producing green alga was screened and labeled Chlorella sp. KLSc59. The effect of extracellular pH, light intensity, external carbon sources, reducing agents, and nutrient deprivation on biohydrogen production of Chlorella sp. KLSc59 were investigated. Hydrogen yield was higher under anaerobic conditions. Under external pH 7.2 with 53.2 μmol photons m−2 s−1 light intensity and using acetate as a carbon source, the optimum hydrogen yield was 281 μmol H<inf>2</inf> mg−1 Chl. Nutrient deprivation reduced the hydrogen yield. Several reducing agents were assessed, and 1 mM ethanol enhanced yield by 3 times for 850 μmol H<inf>2</inf> mg−1 Chl, and 1 mM sodium dithionite increased yield by 2.7 times for 750 μmol H<inf>2</inf> mg−1 Chl. Significantly, our new strain showed higher hydrogen yields ranging from 1.5 to 68 times compared with other microalgae. Thus, Chlorella sp. KLSc59 showed valuable potential for biohydrogen production.
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Improved biohydrogen production by immobilized cells of the green alga Tetraspora sp. CU2551 incubated under aerobic condition
(2020-10-01)
Maswanna, Thanaporn
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Lindblad, Peter
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Maneeruttanarungroj, Cherdsak
The 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−1 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−1 of medium, corresponding to a rate of 182 ± 20 nmol mg−1 DW h−1, 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.
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Biohydrogen production from crude glycerol by two stage of dark and photo fermentation
(2015-06-29)
Chookaew, Teera
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O-Thong, Sompong
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Prasertsan, Poonsuk
Hydrogen production from crude glycerol by two-stage processes of dark fermentation using Klebsiella sp. TR17 and photo fermentation using Rhodopseudomonas palustris TN1 (Rps. palustris TN1) was investigated in batch experiments. In dark fermentation, the cumulative hydrogen production and hydrogen yield was 64.24 mmol H<inf>2</inf>/L and 5.74 mmol H<inf>2</inf>/g COD consumed, respectively with 80.21% of glycerol conversion rate. The dark fermentation effluent (DFE) was employed for photo fermentation. Effect of DFE concentrations (0-5 times dilution), with and without supplementation of yeast extract (2.3 g/L) + NaHCO<inf>3</inf> (0.63 g/L), and glutamate (2-8 mM) were optimized. The optimal conditions for hydrogen production from Rps. palustris TN1 were 5 times dilution of DFE without the supplement of yeast extract + NaHCO<inf>3</inf>, and 2 mM glutamate. Under the optimum conditions, the cumulative hydrogen production of 3.12 mmol H<inf>2</inf>/L and hydrogen yield of 0.68 mmol H<inf>2</inf>/g COD consumed was obtained. The total hydrogen yield of two-stage processes was estimated to be 6.42 mmol H<inf>2</inf>/g COD consumed which was 10.4% of the theoretical yield.

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