Method for growing edible<i>Euglena gracilis</i>in an inexpensive medium with tomato juice to a high cell density equivalent to the density in KH medium

Yamada, Koji; Suzuki, Kengo; Tokunaga, Eiji

doi:10.1039/d3fb00086a

Cited by 3 publications

(4 citation statements)

References 32 publications

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“…C. reinhardtii is recognized for its industrial application as a nutritious food source [ 16 ], comparable to well-known microalgae like Euglena gracilis [ 17 , 18 ], Chlorella , and Spirulina . Notably, it surpasses these in starch and lipid content, earning FDA’s GRAS certification for its safety as a food additive [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Unique Motility of the Unicellular Green Alga Chlamydomonas reinhardtii at Low Temperatures down to −8 °C

Yamashita,

Yamaguchi,

Ikeno

et al. 2024

Micromachines

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Previous studies of motility at low temperatures in Chlamydomonas reinhardtii have been conducted at temperatures of up to 15 °C. In this study, we report that C. reinhardtii exhibits unique motility at a lower temperature range (−8.7 to 1.7 °C). Cell motility was recorded using four low-cost, easy-to-operate observation systems. Fast Fourier transform (FFT) analysis at room temperature (20–27 °C) showed that the main peak frequency of oscillations ranged from 44 to 61 Hz, which is consistent with the 60 Hz beat frequency of flagella. At lower temperatures, swimming velocity decreased with decreasing temperature. The results of the FFT analysis showed that the major peak shifted to the 5–18 Hz range, suggesting that the flagellar beat frequency was decreasing. The FFT spectra had distinct major peaks in both temperature ranges, indicating that the oscillations were regular. This was not affected by the wavelength of the observation light source (white, red, green or blue LED) or the environmental spatial scale of the cells. In contrast, cells in a highly viscous (3.5 mPa·s) culture at room temperature showed numerous peaks in the 0–200 Hz frequency band, indicating that the oscillations were irregular. These findings contribute to a better understanding of motility under lower-temperature conditions in C. reinhardtii.

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Section: Introductionmentioning

confidence: 99%

“…C. reinhardtii is recognized for its industrial application as a nutritious food source [16], comparable to well-known microalgae like Euglena gracilis [17,18], Chlorella, and Spirulina.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Unique Motility of the Unicellular Green Alga Chlamydomonas reinhardtii at Low Temperatures down to −8 °C

Yamashita,

Yamaguchi,

Ikeno

et al. 2024

Micromachines

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“…Aiming to expand the industrial use of E. gracilis for food purposes, we have established a spectroscopic method for identifying carotenoids and hematochrome-like granules (structures resembling the eyespot but suggested not to contain carotenoids [ 29 ]) within single cells [ 30 ]. Additionally, we have developed an efficient cultivation method by growing it in foods, such as tomato juice beverages [ 31 ]. Building on these studies, we found that the carotenoid content in E. gracilis significantly increased when provided with nutrients from food (such as Katsuo dashi, a traditional Japanese fish stock) and an appropriate light environment (strong red light irradiation).…”

Section: Introductionmentioning

confidence: 99%

“…Beyond these typical synthetic growth mediums, studies have been conducted using food and its by-products as substrates for the growth and upcycling of E. gracilis . These studies employed plant-based foods (tomato juice [ 31 ], spent tomato byproduct (STB) [ 35 ], potato liquor [ 36 ], corn steep solid [ 37 ], corn steep liquor and brewer’s spent grain [ 38 ], kinnow peel extract [ 39 ], tofu wastewater [ 40 ], and a mixture of sewage and organic wastes (molasses, corn steep liquor, and waste wine) [ 41 ]). Our research is the first to use an animal-based food (Katsuo dashi; Bonito stock) in this context.…”

Section: Introductionmentioning

confidence: 99%

Reddening of the Unicellular Green Alga Euglena gracilis by Dried Bonito Stock and Intense Red Light Irradiation

Yamashita,

Hanaki,

Mori

et al. 2024

Plants

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This study confirms for the first time that the significant red coloration of Euglena gracilis is induced by bonito stock (BS), a traditional Japanese food, and intense red light exposure (605~660 nm, 1000~1300 µmol photons/m2/s). Under the condition, excessive photosynthetic activity destroyed many chloroplasts, while carotenoids were maintained, resulting in the formation of reddened cells. The HPLC analysis revealed that diadinoxanthin was the primary carotenoid present in reddened cells. Additionally, an undefined xanthophyll, not produced under normal culture conditions, was synthesized and suggested to contain a C=O bond. While it has been reported that strong light stress can increase the total carotenoid content of cells, this study did not verify this claim, and it should be investigated further in future research. Under white light irradiation conditions (90 μmol photons/m2/s) in BS medium, no reddening of cells was observed, and good growth was achieved (over four times the cell density in CM medium in the seventh incubation). This cell suspension is considered to have a high nutritional value because it is composed of functional food, BS and E. gracilis. The fact that this method does not involve genetic modification suggests the possibility of industrial applications, including food use, even in reddened cells.

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Comparative Analysis of Pretreatment Methods for Fruit Waste Valorization in Euglena gracilis Cultivation: Impacts on Biomass, β-1,3-Glucan Production, and Photosynthetic Efficiency

Zhu,

Guo,

Zhao

et al. 2024

Foods

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This study explored the sustainable valorization of fruit waste extracts from sugarcane bagasse (SB), banana peel (BP), and watermelon rind (WR) for Euglena gracilis biomass and β-1,3-glucan production. The extracts were prepared using water extraction (WE), high-temperature and pressure treatment (HTP), and dilute sulfuric acid treatment (DSA). The DSA-treated extracts consistently yielded the best results. E. gracilis cultured in SB-DSA showed the highest cell density with a 2.08-fold increase compared to the commercial HUT medium, followed by BP-DSA (1.35-fold) and WR-DSA (1.70-fold). Photosynthetic pigment production increased significantly, with chlorophyll a yield being highest in SB-DSA (1.90-fold increase). The chlorophyll a/b ratio and total carotenoid content also improved, indicating enhanced light-harvesting capacity and photoprotection. Photosynthetic efficiency, measured by chlorophyll fluorescence, notably improved. The maximum quantum yield of PSII (Fv/Fm) increased by up to 25.88% in SB-DSA, suggesting reduced stress and improved overall photosynthetic health. The potential photochemical efficiency (Fv/F0) showed even greater improvements: up to 40.53% in SB-DSA. Cell morphology analysis revealed larger cell aspect ratios, implying a more active cellular physiological state. β-1,3-glucan yield also increased by 23.99%, 12.92%, and 23.38% in SB-DSA, BP-DSA, and WR-DSA, respectively. This study demonstrates the potential of pretreated fruit waste as a cost-effective and sustainable medium for E. gracilis cultivation, offering the dual benefits of waste valorization and high-value compound production. These findings contribute to the development of more efficient biorefinery processes and align with the circular economy principles in food biotechnology.

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Method for growing edibleEuglena gracilisin an inexpensive medium with tomato juice to a high cell density equivalent to the density in KH medium

Abstract: This paper proposes a low-cost technology for growing Euglena gracilis using beverages that people consume on a daily basis as a nutrient source. Among the 13 beverages tested, the most...

Cited by 3 publications

References 32 publications

Analysis of Unique Motility of the Unicellular Green Alga Chlamydomonas reinhardtii at Low Temperatures down to −8 °C

Analysis of Unique Motility of the Unicellular Green Alga Chlamydomonas reinhardtii at Low Temperatures down to −8 °C

Reddening of the Unicellular Green Alga Euglena gracilis by Dried Bonito Stock and Intense Red Light Irradiation

Comparative Analysis of Pretreatment Methods for Fruit Waste Valorization in Euglena gracilis Cultivation: Impacts on Biomass, β-1,3-Glucan Production, and Photosynthetic Efficiency

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