Appraising different models for predicting biomethane potential: the case of avocado oil processing by-products

Rashama, Charles; Ijoma, Grace N.; Matambo, Tonderayi

doi:10.1007/s10163-020-01116-0

Cited by 13 publications

(6 citation statements)

References 24 publications

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“…Characterisation results were then used to estimate biomethane potentials (BMP) of these substrates according to the methods cited and applied by Rashama et al . 48 . These theoretical BMPs were then compared to experimental values reported by other researchers in literature and discussed in the context of manure codigestion strategies.…”

Section: Methodsmentioning

confidence: 99%

“…Current theoretical methods for predicting biogas yield do not generally consider stability, degradability, and kinetics, despite the strong influence of microbial activity as well as the associated inhibitory or stimulatory effects to the process. Furthermore, these methods tend not to consider the presence of recalcitrant organics (lignin) 35 .…”

Section: Introductionmentioning

confidence: 99%

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Applying PICRUSt and 16S rRNA functional characterisation to predicting co-digestion strategies of various animal manures for biogas production

Ijoma

Nkuna

Mutungwazi

et al. 2021

Sci Rep

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An estimated 25 million tons of animal manure is produced globally every year, causing considerable impact to the environment. These impacts can be managed through the use of anaerobic digestion (AD) This process achieves waste degradation through enzymatic activity, the efficiency of the AD process is directly related to microorganisms that produce these enzymes. Biomethane potential (BMP) assays remain the standard theoretical framework to pre-determine biogas yield and have been used to determine the feasibility of substrates or their combination for biogas production. However, an integrated approach that combines substrate choice and co-digestion would provide an improvement to the current predictive models. PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) addresses the limitations of assays in this regard. In this paper, the biochemical functions of horse, cow, and pig manures are predicted. A total of 135 predicted KEGG Orthologies (KOs) showed amino acids, carbohydrate, energy, lipid, and xenobiotic metabolisms in all the samples. Linear discriminant analysis (LDA) combined with the effect size measurements (LEfSe), showed that fructose, mannose, amino acid and nucleotide sugar, phosphotransferase (PST) as well as starch and sucrose metabolisms were significantly higher in horse manure samples. 36 of the KOs were related to the acidogenesis and/or acetogenesis AD stages. Extended bar plots showed that 11 significant predictions were observed for horse-cow, while 5 were predicted for horse-pig and for cow-pig manures. Based on these predictions, the AD process can be enhanced through co-digestion strategies that takes into account the predicted metabolic contributions of the manure samples. The results supported the BMP calculations for the samples in this study. Biogas yields can be improved if this combined approach is employed in routine analysis before co-digesting different substrates.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Applying PICRUSt and 16S rRNA functional characterisation to predicting co-digestion strategies of various animal manures for biogas production

Ijoma

Nkuna

Mutungwazi

et al. 2021

Sci Rep

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“…The animal feed was obtained by drying and granulating the spent avocado pulp, as described by Serna-Loaiza et al [43]. Biogas was produced by codigesting seeds and peels in an anaerobic digester using the model reported by Rashama et al [44]. Finally, the bioactive compounds were simulated using the methodology reported by Restrepo-Serna et al [45].…”

Section: Small-scale Biorefineriesmentioning

confidence: 99%

“…The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/agronomy13092229/s1, Figure S1: General scheme of guacamole, fertilizer, and biogas production (Small-B1); Figure S2: General scheme of animal feed, fertilizer, and biogas production (Small-B2); Figure S3: General scheme of guacamole, oil, bioactive compounds, fertilizer, and biogas production (Small-B3); Figure S4: General scheme of guacamole, animal feed, bioactive compounds, fertilizer, and biogas production (Small-B4); Table S1: Raw materials, utilities, and parameter economics; Table S2: Inventory of the creole avocado VC in the department of Caldas for the first three links; Table S3: Composition of agrochemicals used in the first two links of the creole avocado VC. References [42][43][44][45][74][75][76][77][78]. Funding: This research was funded by project titled "Análisis de sostenibilidad de diferentes alternativas para la valorización de residuos de aguacate generados en diferentes eslabones de la cadena productiva con un enfoque de análisis de ciclo de vida" code 55239.…”

Section: Supplementary Materialsmentioning

confidence: 99%

Alternatives for the Valorization of Avocado Waste Generated in the Different Links of the Value Chain Based on a Life-Cycle Analysis Approach

Garcia-Vallejo,

Agudelo Patiño,

Poveda-Giraldo

et al. 2023

Agronomy

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This work evaluates the sustainability of small-scale biorefineries as a potential enterprise alternative to be introduced in rural areas based on experimental and simulation data. Four scenarios were evaluated: the first scenario involves the production of guacamole, the second involves the production of animal feed, and the third and fourth scenarios involve the extraction of bioactive compounds and the production of avocado oil or animal feed, respectively. In addition, all scenarios produce biogas and fertilizer. Each of the scenarios were evaluated considering the technical, economic, environmental, and social aspects. As a main result, the first scenario showed the lowest operating and investment costs, as well as the lowest economic profitability (profit margin 35%). On the other hand, the third and fourth scenarios present the highest investment and operating expenses (OpEx USD 6.2 million per year and CapEx USD 1.0 million), but their profit margins are in the 60–70% range. Furthermore, a life-cycle assessment (LCA) was carried out and allows inferring that the transformer link presents the highest environmental impact of the entire value chain and that the carbon footprint for all scenarios ranges between 1.01–2.41 kg CO2 eq per kg avocado. Similarly, the social impact methodology shows that the proposed scenarios do not present any social risk. Thus, the biorefinery for animal feed, bioactive compounds, biogas, and fertilizer was selected as the best option to be implemented in Caldas.

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“…It is widely agreed among researchers across the globe that in AD studies, the substrate's BMP is proportional to its volatile matter content, which is a function of the substrate's organic elemental (CHNO) analysis [10]. There are several methods of estimating a substrate's BMP based on its elemental analysis results [11]. One common calculation approach is the Buswell equation, which gives a theoretically determined BMP.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa

et al. 2023

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The biodegradability of water hyacinth for biogas and biofertilizer production was studied under mesophilic conditions. The effects of water hyacinth pretreatments were also included in this investigation. It was found that water hyacinth has a low biodegradability of 27% when monodigested, while in a 3:1 ratio with cow manure, the biodegradability increases to 46%. At this elevated biodegradability, the water hyacinth biomethane potential was 185 LCH4/kgVS, while that of cow manure was 216 LCH4/kgVS. The Gompertz kinetic model had superior parameters than the logistic model for most of the water hyacinth–cow manure combined substrate digestion. Based on the Gompertz model, the lag phase and daily maximum methane production rate were 5.5 days and 22.9 mL/day, respectively, for the 3:1 codigestion (R2 of 0.99). These values were 6.7 days and 15.2 mL/day, respectively, in the case of water hyacinth monodigestion (R2 = 0.996). The dominant microbial species detected in the digestates were Bacteroidetes and Proteobacteria. A few microbial species were indigenous to water hyacinth, but more diverse consortia, which are key to efficient substrate biodegradation, came from cow manure. The digestate contained ammonium nitrogen at 68 mg/kg with phosphorous and potassium at 73 and 424 mg/kg, respectively. Nitrogen was lower but phosphorous and potassium were comparable to previously studied digestates of other substrates. Only water hyacinth pretreated by aerobic composting was proven to unlock a higher methane yield that matched the 3:1 codigestion with cow manure. Other pretreatments induced better biodegradation performance than that observed in untreated water hyacinth but these improvements were not as good as that of the 3:1 codigestion scheme. It was concluded that water hyacinth sourced from the Hartbeespoort Dam could be treated by anaerobic digestion to recover biogas and biofertilizer. However, more experiments are required to fully understand and harness the optimisation opportunities available in applying this technology to manage water hyacinths.

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Appraising different models for predicting biomethane potential: the case of avocado oil processing by-products

Cited by 13 publications

References 24 publications

Applying PICRUSt and 16S rRNA functional characterisation to predicting co-digestion strategies of various animal manures for biogas production

Applying PICRUSt and 16S rRNA functional characterisation to predicting co-digestion strategies of various animal manures for biogas production

Alternatives for the Valorization of Avocado Waste Generated in the Different Links of the Value Chain Based on a Life-Cycle Analysis Approach

Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa

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