Evaluation of a sludge-treatment process comprising lipid extraction and drying using liquefied dimethyl ether

Wang, Quan; Oshita, Kazuyuki; Nitta, Takashi; Takaoka, Masaki

doi:10.1080/09593330.2020.1730982

Cited by 17 publications

(16 citation statements)

References 48 publications

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“…The relatively highest proportion of FAMEs was obtained using the DME method (31.7% of 1st process, 13.0% of 2nd process), followed by 15.4% with B&D (dry), 10.0% with B&D (wet), and 5.3% with Soxhlet extraction (HE). These values are consistent with the ndings in previous studies [25]. In addition, signi cant differences were observed in FAME pro les among extraction methods, as shown in Fig.…”

Section: Dme-based Extraction With An Ethanol-acetone Entrainersupporting

confidence: 93%

“…Thus, DME is suitable for extraction of lipids from wet biomass samples with simultaneous dewatering. This combined process represents considerable energy savings [24] [25]. In addition, DME is a gas under ambient conditions; thus, it can be easily lique ed at 0.51-0.59 MPa and room temperature (20-25 °C).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, DME is a gas under ambient conditions; thus, it can be easily lique ed at 0.51-0.59 MPa and room temperature (20-25 °C). The low boiling point of DME (i.e., -25 °C) allows it to be easily removed via evaporation for recycling/reuse [25] [26].…”

Section: Introductionmentioning

confidence: 99%

“…DME has been successfully applied for extraction of lipids and removal of moisture from dewatered biomass, including sludge [25] [27], cattle manure [28], microalgae [29] and vegetables [30]; however, its use with merely thickened samples has not been studied. This is largely because its low polarity results in immiscibility with microalgae suspended in water.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Method for Extraction of Lipids From Liquid Microalgae Without Dewatering

Wang

Oshita

Takaoka

2020

Preprint

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Background: Recent studies of lipid extraction from microalgae have focused primarily on dewatered or dried samples, and the processes are simple with high lipid yield. Yet, the dewatering with drying step is energy-intensive, which makes the energy output from the extracted lipid is less than the energy needed to produce it. Thus, exploring an extraction technique for just a thickened sample without the dewatering, drying and auxiliary operation (such as cell disruption) is very significant. Whereas lipid extraction from the thickened microalgae is complicated by the high-water content involved, and traditional solvent hence cannot work well. Dimethyl ether (DME), a green solvent, featuring a high affinity for both water and organic compounds with an ability to penetrate the cell walls, has the potential to achieve this goal. Results: This study investigated an energy-saving method for lipid extraction using DME as the solvent with an entrainer solution (ethanol and acetone) for flocculation thickened microalgae. Extraction efficiency was evaluated in terms of extraction time, DME dosage, entrainer dosage, and ethanol:acetone ratio. Optimal extraction occurred after 30 minutes using 4.2 mL DME per 1 mL microalgae, with an entrainer dosage of 8% at 1:2 ethanol:acetone. Raw lipid yields and fatty acid methyl ester contents were compared against those of common extraction methods (Bligh & Dryer and Soxhlet). Thermal gravimetry/differential thermal analysis, Fourier-transform infrared spectroscopy, and C/H/N elemental analyses were used to examine differences in lipids extracted using each of the evaluated methods. Considering influence of trace metals on biodiesel utilization, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy analyses were used to quantify trace metals in the extracted raw lipids, which revealed relatively high concentrations of Mg, Na, K, and Fe.Conclusions: Our DME-based method recovered 26.4% of total raw lipids and 54.4% of total fatty acid methyl esters at first extraction with remnants being recovered by a 2nd extraction. In additional, the DME-based approach was more economical than other methods, because it enabled simultaneous dewatering with lipid extraction and no cell disruption was required. The trace metals of raw lipids indicated a purification demand in subsequent refining process.

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Section: Dme-based Extraction With An Ethanol-acetone Entrainersupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Novel Method for Extraction of Lipids From Liquid Microalgae Without Dewatering

Wang

Oshita

Takaoka

2020

Preprint

Self Cite

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show abstract

“…Thus, DME is suitable for extraction of lipids from wet biomass samples with simultaneous dewatering. This combined process represents considerable energy savings [24,25]. In addition, DME is a gas under ambient conditions; thus, it can be easily liquefied at 0.51-0.59 MPa and room temperature (20-25 °C).…”

mentioning

confidence: 99%

Effective lipid extraction from undewatered microalgae liquid using subcritical dimethyl ether

Wang

Oshita

Takaoka

2021

Biotechnol Biofuels

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Background Recent studies of lipid extraction from microalgae have focused primarily on dewatered or dried samples, and the processes are simple with high lipid yield. Yet, the dewatering with drying step is energy intensive, which makes the energy input during the lipid production more than energy output from obtained lipid. Thus, exploring an extraction technique for just a thickened sample without the dewatering, drying and auxiliary operation (such as cell disruption) is very significant. Whereas lipid extraction from the thickened microalgae is complicated by the high water content involved, and traditional solvent, hence, cannot work well. Dimethyl ether (DME), a green solvent, featuring a high affinity for both water and organic compounds with an ability to penetrate the cell walls has the potential to achieve this goal. Results This study investigated an energy-saving method for lipid extraction using DME as the solvent with an entrainer solution (ethanol and acetone) for flocculation-thickened microalgae. Extraction efficiency was evaluated in terms of extraction time, DME dosage, entrainer dosage, and ethanol:acetone ratio. Optimal extraction occurred after 30 min using 4.2 mL DME per 1 mL microalgae, with an entrainer dosage of 8% at 1:2 ethanol:acetone. Raw lipid yields and its lipid component (represented by fatty acid methyl ester) contents were compared against those of common extraction methods (Bligh and Dryer, and Soxhlet). Thermal gravimetry/differential thermal analysis, Fourier-transform infrared spectroscopy, and C/H/N elemental analyses were used to examine differences in lipids extracted using each of the evaluated methods. Considering influence of trace metals on biodiesel utilization, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy analyses were used to quantify trace metals in the extracted raw lipids, which revealed relatively high concentrations of Mg, Na, K, and Fe. Conclusions Our DME-based method recovered 26.4% of total raw lipids and 54.4% of total fatty acid methyl esters at first extraction with remnants being recovered by a 2nd extraction. In additional, the DME-based approach was more economical than other methods, because it enabled simultaneous dewatering with lipid extraction and no cell disruption was required. The trace metals of raw lipids indicated a purification demand in subsequent refining process.

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Ethanol‐free extraction of resveratrol and its glycoside from Japanese knotweed rhizome by liquefied dimethyl ether without pretreatments

Kanda

Oishi

Machmudah

et al. 2020

Asia-Pacific J Chem Eng

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Herein, we carried out the extraction of polyphenol resveratrol and its glycoside (piceid) from raw Japanese knotweed via a simple method, employing dimethyl ether (DME) as the solvent. With DME extraction, the conventional drying and cell wall disruption steps can be left out. As a result, more resveratrol and piceid were obtained in DME extraction than in conventional ethanol extraction. Because the Hansen solubility parameters of DME are closer to ethanol than to water, it allowed us to extract resveratrol and piceid from raw Japanese knotweed, unlike water. Simultaneously, 83.5% of the initial water and 213 mg/g dry of organic extracts were extracted from raw Japanese knotweed. As DME extraction does not involve drying and grinding of the decomposed antioxidants, it is highly suitable for extracting antioxidants.

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Evaluation of a sludge-treatment process comprising lipid extraction and drying using liquefied dimethyl ether

Cited by 17 publications

References 48 publications

A Novel Method for Extraction of Lipids From Liquid Microalgae Without Dewatering

A Novel Method for Extraction of Lipids From Liquid Microalgae Without Dewatering

Effective lipid extraction from undewatered microalgae liquid using subcritical dimethyl ether

Ethanol‐free extraction of resveratrol and its glycoside from Japanese knotweed rhizome by liquefied dimethyl ether without pretreatments

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