BMP testingFruit, vegetables and their residues

Bananas (fruit, pulp) — BMP: 6 studies, weighted mean 336 m³ CH₄/t VS

Bananas (fruit, flesh, whole with peel) digest well thanks to starch and sugars; the result depends on ripeness, the share of peel and the test conditions.

CH₄ ≈ 52 % (estimate)

Published 25 October 2021Updated 29 October 20263 min readFeedstockData Editorial Team

Photo Wilfredor / Wikimedia Commons, licence CC BY-SA 3.0, source file; changes: cropping

Weighted mean: 336m³ CH₄/t VS
Range: 289–367m³ CH₄/t VS
Records: 6studies
Publications: 4sources
Temperatures: 35 °C, 37 °C, 55 °Cof the test

Methane in biogas

≈51–54% CH₄

Medium methane content · ≈ 5.2 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (carbohydrate-dominated (no protein or fat characteristics)) and the yields of compound groups according to FNR.

How we calculate it and what the zones mean

Rating for biogas plants

not rated — editorial rating for biogas plants

Not rated: no dry matter or volatile solids in the data. We calculate the rating when the dry matter and volatile solids of the material are known.

Editorial rating per the methodology

Add to the co-digestion calculator CSV data

BMP curves from 6 studies

Weighted mean Individual records

Dashed lines are a model curve (first-order kinetics, B(t) = B₀·(1 − e^−kt)); the end point comes from the publication. All curves are model curves.

Cumulative methane production over the test [m³ CH₄/t VS]. The thick line is the weighted mean of all records (336); dots mark the end values given in the publications. Point at the chart to read values; click a legend item to hide or show a record.

Records and sources

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Source	BMP m³ CH₄/t VS	Temperature	Sample	Curve
Buffiere et al. (2006) DOI	289	55 °C · thermophilic	Banana	end point (model curve)
Khan M.T. (2016) · 1	349	37 °C · mesophilic	Unpeeled banana	end point (model curve)
Khan M.T. (2016) · 2	367	37 °C · mesophilic	Banana flesh	end point (model curve)
Kouas et al. (2017) DOI	361	35 °C · mesophilic	banana	end point (model curve)
Sanjaya et al. (2016) · 1 DOI	321	35 °C · mesophilic	Fresh ripe banana pulp	end point (model curve)
Sanjaya et al. (2016) · 2 DOI	351	35 °C · mesophilic	Rooten banana pulp	end point (model curve)
Weighted mean	336	arithmetic mean 340, SD 29

Typical composition

Dry matter (DM): 20.4% (range 18–22.9)

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 2 determinations, volatile solids: 0 determinations.

Sources: Sanjaya et al. (2016).

The composition of the raw material varies between batches — for plant calculations use an analysis of your own sample. The calculator inserts typical values automatically.

Process properties

easily degradable
carbon-rich
low in nitrogen
poor in trace elements
seasonal
acidic
editorial classification

Low confidence: the description is based on general characteristics of the substrate group, not on studies of this material. Treat it as a hint to be verified.

Advantages

Methane yield in the compendium: median 350 (range 289-367) m³ CH₄/t VS, 6 records from 4 studies (weighted mean 336).
The kinetics of methane production from banana waste were modelled in a batch study (Khan M.T. (2016))

Drawbacks and risks

In the digestion of cassava waste, rich in easily degradable sugars and poor in nitrogen, the literature indicates early inhibition through rapid acidification; an analogous risk applies to other starchy substrates (Ahou et al. (2021))

Co-digestion — what to combine it with, what to watch out for

combines well
substrates: nitrogen-rich — e.g. Pig slurry, Poultry manure, Waste activated sludge (secondary sludge), Chlorella vulgaris, Nannochloropsis salina
A nitrogen-rich co-substrate balances the low C/N of fruit and vegetable waste (Bouallagui et al. 2009).^[1]
combines well
substrates: high alkalinity (buffer) — e.g. Cattle manure, Pig slurry, Cattle slurry, Duck slurry, Rumen and digestive tract content
Co-digestion of easily degradable substrates with dairy slurry increased the methane yield relative to slurry alone.^[2]

Dosing

No source limits on the dose for this substrate.

Introduce gradually, starting with a small dose and monitoring the process (e.g. FOS/TAC, pH, gas composition).

Practical requirements

Shred: the yield depends on particle size (ground banana peels gave more than chopped ones) (Odedina et al. (2017); Sharma et al. (1988))

Sources of the process data

The co-digestion calculator will assess a specific mixture containing this substrate.

What it is and where it comes from

Bananas are grown in the tropical zone, and reach Poland as imports. Banana waste therefore arises in ripening rooms, wholesale markets and shops (overripe, damaged fruit), and in the growing countries also on plantations and in processing (peels, rejects). The dataset contains samples of fresh and spoiled flesh, whole fruit with peel and fruit with no description, tested mainly at mesophilic temperature and one test at thermophilic temperature.

Properties relevant to digestion

The flesh of a ripe banana contains a lot of readily available sugars (sucrose, glucose, fructose), and that of an unripe one mainly starch, so degradation is rapid and requires careful dosing to avoid acidification. The peel contains more fibre, lignin and polyphenols, and its share reduces digestibility. Low dry matter and high moisture content make storage difficult, and spoiled fruit loses its readily available sugars more quickly. The protein content is low, so the C/N ratio is high relative to meat waste.

How to read the spread of results

The records differ in the part of the fruit (flesh, peel, whole fruit), ripeness and degree of spoilage, and also in variety. Size reduction, temperature (the dataset also includes thermophilic tests), inoculum, the substrate-to-inoculum ratio and test length are significant. Results for flesh will differ from those for whole fruit with peel, and the dataset combines these variants in a single substrate.

In biogas plant practice

Banana waste is a valuable co-substrate in a mixture with slurry or nitrogen-rich material. It should be processed quickly, size-reduced and dosed evenly with control of pH and volatile acids. Peels require more thorough size reduction. Fruit waste is usually classified as waste (group 02 or 20), and its acceptance requires installation permits; for imported fruit, additional phytosanitary requirements may apply.

For comparison with domestic fruit such as apples, bananas contain more starch when unripe and fewer organic acids. This affects the initial course of digestion: degradation may be slower at first and then abrupt, which is worth taking into account in dosing.

Because the dataset is small, it is best to confirm the result with your own BMP test on the specific batch.

Methodology in brief

BMP is the amount of methane obtained from volatile solids (VS) in a batch test, given in m³ CH₄ per tonne of VS (numerically the same as NmL CH₄/g VS in the publications) and converted to normal conditions (0 °C, 101.325 kPa). The weighted mean gives each publication a total weight of 1, split equally between its results for the substrate — a paper testing twenty varieties does not outweigh a paper with a single sample. In inter-laboratory programmes the unit is the laboratory (total weight 1), and within it the weight of a test grows with the number of bottles (replicates). Results after pretreatment (e.g. thermal, chemical, enzymatic) are shown separately and are not included in the mean.

Solid lines are curves measured in the tests. Where a publication gives only the final result, we draw a first-order kinetic model, B(t) = B₀·(1 − e^−kt): only the end point comes from the publication, and the shape of the curve serves purely as visualisation — do not read the production on a particular day from it. For this substrate k = 0.245 d⁻¹ was assumed (median of rate constants k reported in the sources and/or fitted to the mean measured curves).

The statistics describe the spread of published results — a descriptive compilation, not a meta-analysis or a guarantee of plant yield.

Full methodology and correction policy

Bibliography

All sources of the site: bibliography.