Spent Coffee Grounds Alkaline Pre-treatment as Biorefinery Option to Enhance their Anaerobic Digestion Yield

Girotto, Francesca; Lavagnolo, Maria Cristina; Pivato, Alberto

doi:10.1007/s12649-017-0033-8

Cited by 39 publications

(33 citation statements)

References 47 publications

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“…This high increase was probably due to fine grinding of the substrate to obtain a sort of fine powder. As already demonstrated by similar studies (Girotto et al, 2017b;Pellera et al, 2016;Torres and Lloréns, 2008), NaOH contributes effectively to the hydrolysation of complex organic matter, resulting in transfer of the matter from the solid to the liquid phase.…”

Section: Spent Coffee Groundsmentioning

confidence: 57%

“…Research was carried out in two experimental runs. The first trial used spent coffee grounds (SCG) and orange peels (OP) both as single substrates and mixed together; SCG were pre-treated with NaOH on the basis of previous results obtained by Girotto et al (2017b). The second trial used brewer spent grains (BSG) as substrate and evaluated the effect of acid and alkaline pre-treatment in the presence of two different initial fermentation pH values, namely 7 and 9.…”

Section: Methodsmentioning

confidence: 99%

“…SCG is a lignocellulosic material and, with a view to exploiting this residue as a source of energy, a series of pre-treatments (Girotto et al, 2017d;Kovalcik et al, 2018), including acidic, alkaline, oxidative, steam explosion, and thermo-chemical pre-treatments was applied, with alkaline pre-treatment proving to be one of the best performing applications (Chaturvedi and Verma, 2013).…”

Section: Coffee Production Residuesmentioning

confidence: 99%

“…2.2.1 SCG alkaline pre-treatment SCG were mixed evenly with a NaOH solution, 8% w/w (Girotto et al, 2017b), at a pH higher than 12. The NaOHsoaked SCG were kept at constant room temperature (20 ± 0.5°C) in 250 mL glass bottles for 24 h. At the end of the pre-treatment, samples were taken for compositional analysis before acidogenic fermentation tests.…”

Section: Substrates Pre-treatmentsmentioning

confidence: 99%

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Biological Metabolites Recovery From Beverage Production Solid Residues Through Acidogenic Fermentation

2019

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Acidogenic fermentation was applied to evaluate the potential recovery of biological monomers as precursors in bio-plastic production. Three residual organic substrates from high-volume beverage sectors (coffee, orange juice, beer) were assessed: spent coffee grounds (SCG), orange peels (OP), and brewers' spent grains (BSG). Batch fermentation tests were set up. SCG and OP were studied as single substrates and combined to evaluate yields of target monomers (volatile fatty acids, ethanol, lactate) and to reveal interactions between the matrixes. NaOH pre-treatment was applied to SCG to enhance disruption of the lignocellulosic cell wall. BSG was studied without pre-treatment and following acid or alkaline pre-treatment, with acidogenic fermentation being initiated with two different initial pH values (7; 9). Acetogenic fermentation was achieved with all substrates, although with different yields of target monomers. In terms of total biological metabolite production, following alkaline pre-treatment, OP and BSG, both fermented at an initial pH 9, showed the best performance, yielding 62.6 g and 62.0 g target monomers per litre substrate. For all substrates, acetic and butyric acids were the most abundant products. In the case of OP fermentation, butyrate accounted for 57% (35.8 g/L) of the total. The BSG test with the highest total yield also achieved the highest acetate yield (36.7 g/L). The results confirm that OP and BSG should be considered a priority sustainable feedstock for the supply of biological monomers, particularly if polyhydroxyalkanoates are to be produced. SCG are better suited to aceto-oriented approaches, such as the production of polyvinyl acetate.

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Section: Spent Coffee Groundsmentioning

confidence: 57%

Section: Methodsmentioning

confidence: 99%

Section: Coffee Production Residuesmentioning

confidence: 99%

Section: Substrates Pre-treatmentsmentioning

confidence: 99%

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Biological Metabolites Recovery From Beverage Production Solid Residues Through Acidogenic Fermentation

2019

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“…The combined adverse effect of high NaOH dose and temperature is clearly seen in the upper right region of the Ym response surface plot (Figure 4). In a recent study, alkaline pretreatment of SCG was performed using NaOH doses of 2-8% of the substrate on a dry weight basis (100 g of SCG was suspended in 100 mL NaOH solution of different molarities in the range of 0.19-0.74 M) for 24 h [22]. There was no inhibitory effect of NaOH, within the tested concentration range, and the maximum Ym was obtained for SCG pretreated with the highest NaOH dose.…”

Section: Correlation Between Sd and Ymmentioning

confidence: 99%

Effect of Mild-Temperature Thermo-Alkaline Pretreatment on the Solubilization and Anaerobic Digestion of Spent Coffee Grounds

Kim

Lee

2018

Energies

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Abstract:Mild-temperature thermo-alkaline pretreatment of spent coffee grounds (SCG) was studied to improve its solubilization and methanation. The simultaneous effects of NaOH concentration (0-0.2 M) and temperature (60-90 • C) were investigated. Significant solubilization of SCG was achieved by the pretreatment, particularly under high-NaOH-concentration and high-temperature conditions. However, adding NaOH above a certain concentration adversely affected the methane production. Therefore, the degree of solubilization (SD) correlated poorly with methane yield (Ym). Response surface models of SD and Ym were successfully generated. The maximum response of SD (36.4%) was obtained at 0.18 M NaOH and 90.0 • C, while that of Ym (263.31 mL CH 4 /g COD added) was obtained at 0.13 M NaOH and 70.5 • C. Hydrogenotrophic Methanospirillum species were the dominant methanogens in all the SCG digestion tests. It is likely that NaOH concentration had a more significant influence on the development of microbial community structure, particularly of methanogens than temperature.

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Effect of alkaline‐treated spent coffee grounds and compatibilizer on the mechanical properties of bio‐composite based on polypropylene matrix

Thanh,

Tan,

Trung

et al. 2023

Vietnam Journal of Chemistry

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In this study, the effect of alkaline‐treated spent coffee grounds and compatibilizer on the mechanical properties of bio‐composite based on polypropylene (PP) matrix was investigated. After alkaline treatment, the surface of spent coffee grounds became rougher; hence the PP matrix could better adsorb and encapsulate the treated coffee grounds compared with that of untreated ones. The TGA analysis shows that the alkaline treated spent coffee grounds had better thermal properties than the untreated ones. When increasing the weight percentage of spent coffee grounds from 10 to 20, the tensile strength and flexural strength of PP‐based composite decreased. These mechanical properties of PP‐based composite containing treated coffee grounds were enhanced compared with that containing untreated coffee grounds due to the better dispersion of treated coffee grounds into the PP matrix. The presence of polypropylene‐graft‐maleic anhydride (PP‐g‐MA) compatibilizer at the content of 1, 3, and 5 wt% led to a significant increase the mechanical properties of PP‐based bio‐composites, reaching the highest tensile strength of 22.7 MPa and flexural strength of 17.3 MPa. Therefore, the alkaline‐treated spent coffee ground is a potential additive for producing bio‐composite with the advantages of being light and easy to naturally decompose.

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Spent Coffee Grounds Alkaline Pre-treatment as Biorefinery Option to Enhance their Anaerobic Digestion Yield

Cited by 39 publications

References 47 publications

Biological Metabolites Recovery From Beverage Production Solid Residues Through Acidogenic Fermentation

Biological Metabolites Recovery From Beverage Production Solid Residues Through Acidogenic Fermentation

Effect of Mild-Temperature Thermo-Alkaline Pretreatment on the Solubilization and Anaerobic Digestion of Spent Coffee Grounds

Effect of alkaline‐treated spent coffee grounds and compatibilizer on the mechanical properties of bio‐composite based on polypropylene matrix

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