Hydrothermal synthesis of novel two-dimensional α-quartz nanoplates and their applications in energy-saving, high-efficiency, microalgal biorefineries

Moon, Gyuseop; Lee, Nakyeong; Kang, Sungsu; Kim, Young-Eun; Lee, Sang‐Ah; Chitumalla, Ramesh Kumar; Jang, Joonkyung; Choe, Youngson; Oh, You-Kwan; Chung, Sungwook

doi:10.1016/j.cej.2020.127467

Cited by 12 publications

(24 citation statements)

References 96 publications

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“…The freeze-dried cells were stored in a vacuum bag at −20 • C until further use. The astaxanthin content was measured using a high-performance liquid chromatography (HPLC) instrument (Agilent 1260 Infinity, Hewlett-Packard, Santa Clara, CA, USA) equipped with a diode-array detector and a YMC Carotenoid column (250 mm × 4.6 mm, 5 µm, YMC Inc., Kyoto, Japan), as previously described [15,23]. Briefly, ca.…”

Section: Other Analytical Methodsmentioning

confidence: 99%

Electric Stimulation of Astaxanthin Biosynthesis in Haematococcus pluvialis

et al. 2021

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The green microalga Haematococcus pluvialis accumulates astaxanthin, a potent antioxidant pigment, as a defense mechanism against environmental stresses. In this study, we investigated the technical feasibility of a stress-based method for inducing astaxanthin biosynthesis in H. pluvialis using electric stimulation in a two-chamber bioelectrochemical system. When a cathodic (reduction) current of 3 mA (voltage: 2 V) was applied to H. pluvialis cells for two days, considerable lysis and breakage of algal cells were observed, possibly owing to the formation of excess reactive oxygen species at the cathode. Conversely, in the absence of cell breakage, the application of anodic (oxidation) current effectively stimulated astaxanthin biosynthesis at a voltage range of 2–6 V, whereas the same could not be induced in the untreated control. At an optimal voltage of 4 V (anodic current: 30 mA), the astaxanthin content in the cells electro-treated for 2 h was 36.9% higher than that in untreated cells. Our findings suggest that electric treatment can be used to improve astaxanthin production in H. pluvialis culture if bioelectrochemical parameters, such as electric strength and duration, are regulated properly.

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Section: Other Analytical Methodsmentioning

confidence: 99%

Electric Stimulation of Astaxanthin Biosynthesis in Haematococcus pluvialis

et al. 2021

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“…Ultrathin α-quartz NPLs (lateral size, 1.14 ± 0.32 µm; thickness, 7.7 ± 0.6 nm) were synthesized from monodisperse amorphous silica nanoparticles (average diameter: 60 nm) according to a previously reported template-free hydrothermal protocol [13]. The synthesized white α-quartz NPL powder was stored at room temperature (~28 • C) until the algae experiments.…”

Section: Methodsmentioning

confidence: 99%

“…In particular, cell encystment is accompanied by the formation of a rigid multilayered cell wall structure. The cell wall thickness (~4 µm) of H. lacustris cysts is significantly greater than that of Chlamydomonas (~351 nm), which is extensively used in various algal biorefineries [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, we reported the synthesis of ultrathin α-quartz nanoplates (NPLs) using a novel template-free hydrothermal method; we demonstrated their disruptive effect on algal cell walls for subsequent dichloromethane/methanol (DCM/MeOH) solvent extraction [13]. Here, we aimed to investigate the technical feasibility of room-temperature IL-based astaxanthin extraction from rigid H. lacustris cysts using α-quartz NPLs as cellwall disrupters.…”

Section: Introductionmentioning

confidence: 99%

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Room-Temperature Cell Disruption and Astaxanthin Recovery from Haematococcus lacustris Cysts Using Ultrathin α-Quartz Nanoplates and Ionic Liquids

et al. 2022

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Ionic liquids (ILs) are new green solvents, which are widely used in lignocellulosic and microalgal biorefineries. However, high-temperature operating conditions limit their application in the extraction of heat-labile algal products, such as bioactive astaxanthin. In this study, we report the technical feasibility of room-temperature astaxanthin extraction from Haematococcus lacustris cysts with a thick and complex cell wall structure, by combining ultrathin α-quartz nanoplates (NPLs) with ethyl-3-methylimidazolium ([Emim])-based ILs. When four different [Emim]-based ILs with thiocyanate (SCN), diethylphosphate (DEP), HSO4, and Cl anions were applied to 90-day-old H. lacustris cysts at room temperature (~28 °C), the astaxanthin extraction efficiency was as low as 9.6-14.2%. Under sonication, α-quartz NPLs disrupted the cyst cell wall for a short duration (5 min). The astaxanthin extraction efficacies of a subsequent IL treatment improved significantly to 49.8% for [Emim] SCN, 60.0% for [Emim] DEP, 80.7% for [Emim] HSO4, and 74.3% for [Emim] Cl ions, which were 4.4, 6.1, 8.4, and 5.2 times higher than the extraction efficacy of only ILs, respectively. This finding suggests that α-quartz NPLs can serve as powerful cell-wall-disrupting agents for the room-temperature IL-mediated extraction of astaxanthin from robust algal cyst cells.

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“…Astaxanthin content was measured using high-performance liquid chromatography (HPLC, Agilent 1260 Infinity system, Agilent Technologies, Santa Clara, CA, USA) equipped with a diodearray detector and a YMC carotenoid column (4.6 mm (ID] × 250 mm [length], 5 µm [particle size]; YMC Inc., Kyoto, Japan). The detailed HPLC conditions are available in our previous publications [2,19].…”

Section: Astaxanthin and Fatty Acid Quantificationmentioning

confidence: 99%

Enhancement of Astaxanthin and Fatty Acid Production in Haematococcus pluvialis Using Strigolactone

et al. 2022

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Improving the production rate of high-value nutraceutical compounds, such as astaxanthin and polyunsaturated fatty acids (PUFAs), is important for the commercialization of Haematococcus pluvialis biorefineries. Here, the effects of a phytohormone, strigolactone analog rac-GR24, on cell growth and astaxanthin and fatty acid biosynthesis in H. pluvialis were investigated. Four concentrations (2, 4, 6, and 8 µM) of rac-GR24 were initially added during 30 days of photoautotrophic cultivation. The addition of rac-GR24 improved cell number density and chlorophyll concentration in H. pluvialis cultures compared to the control; the optimal concentration was 8 µM. Despite a slightly reduced astaxanthin content of 30-d-old cyst cells, the astaxanthin production (26.1 ± 1.7 mg/L) improved by 21% compared to the rac-GR24-free control (21.6 ± 1.5 mg/L), owing to improved biomass production. Notably, at the highest dosage of 8 µM rac-GR24, the total fatty acid content of the treated H. pluvialis cells (899.8 pg/cell) was higher than that of the untreated cells (762.5 pg/cell), resulting in a significant increase in the total fatty acid production (361.6 ± 48.0 mg/L; 61% improvement over the control). The ratio of PUFAs, such as linoleic (C18:2) and linolenic (C18:3) acids, among total fatty acids was high (41.5–44.6% w/w) regardless of the rac-GR24 dose.

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Hydrothermal synthesis of novel two-dimensional α-quartz nanoplates and their applications in energy-saving, high-efficiency, microalgal biorefineries

Cited by 12 publications

References 96 publications

Electric Stimulation of Astaxanthin Biosynthesis in Haematococcus pluvialis

Electric Stimulation of Astaxanthin Biosynthesis in Haematococcus pluvialis

Room-Temperature Cell Disruption and Astaxanthin Recovery from Haematococcus lacustris Cysts Using Ultrathin α-Quartz Nanoplates and Ionic Liquids

Enhancement of Astaxanthin and Fatty Acid Production in Haematococcus pluvialis Using Strigolactone

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