About usContact

BMP testingFruit, vegetables and their residues

Dragon fruit (pitaya) peels — BMP: 3 studies, weighted mean 87 m³ CH₄/t VS

Pitaya (dragon fruit) peels are a fibrous waste with a very large spread of results from several studies; this is influenced by pulp residue, mucilage and sample drying.

CH₄ ≈ 53 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

Photo Billjones94 / Wikimedia Commons, licence CC BY-SA 4.0, source file; changes: cropping

Weighted mean
87m³ CH₄/t VS
Range
30–195m³ CH₄/t VS
Records
3studies
Publications
3sources
Temperatures
—of the test

Methane in biogas

Medium methane content · ≈ 5.3 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (protein from total nitrogen (N 1.5 % DM × 6.25)) 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 3 studies

Weighted mean Individual records

BMP curves: Dragon fruit (pitaya) peelsCumulative methane production over time for 3 records and the weighted mean of 87 m³ CH₄/t VS. 3 of the curves are model curves (first-order kinetics).050100150200250051015202530time [d]m³ CH₄/t VSZhao et al. (2016): 195 m³ CH₄/t VS (model curve)Muenmee i Prasertboonyai (2021): 30 m³ CH₄/t VS (model curve)Zheng et al. (2025): 35 m³ CH₄/t VS (model curve)mean87

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 (87); 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

Download CSV
SourceBMP
m³ CH₄/t VS		TemperatureSampleCurve
Zhao et al. (2016) DOI195—Pitaya (Hylocereus undulatus) – Peelend point (model curve)
Muenmee i Prasertboonyai (2021) DOI30—Dragon fruit peelend point (model curve)
Zheng et al. (2025) DOI35—Control-DFP (dragon fruit peel, mono-digestion)end point (model curve)
Weighted mean87arithmetic mean 87, SD 94

Typical composition

Volatile solids (VS)
81.4 % DM (range 81.4–81.4)
Nitrogen
1.5 % DM
C/N ratio
23.7

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: BCBPD); dry matter: 0 determinations, volatile solids: 1 determination. C/N was calculated as the ratio of C and N content (% DM) from the same source. No DM in the sources – the calculator has to ask for a value.

Sources: Zhao 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

  • fibrous
  • slowly degrading
  • seasonal
  • variable composition
  • dilutes the feed (low DM)
  • editorial classification

Advantages

  • Methane yield in the compendium: median 35 (range 30–195) m³ CH₄/t VS, 3 records from 3 papers (weighted mean 87).
  • Pitaya peel improved the digestion of poultry manure: the highest yield at a slurry:peel ratio of 25:75, with low VFA (<0.5 g/l) at the end of the test (Zheng et al. (2025))
  • Co-digestion of peel with food waste was studied (Muenmee 2021) (Muenmee et al. (2021))

Drawbacks and risks

  • Pitaya peel in mono-digestion gave a very low yield compared with co-digestion with poultry manure (Zheng et al. (2025))

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

Dosing

Zheng et al. (2025): in BMP tests the highest yield was given by a poultry manure:peel mix of 25:75 (the basis of the ratio was not given in the abstract); VFA at the end of the test below 0.5 g/l. A result from a batch test is not a dose limit for a continuous reactor, so max_share remains empty.

Sources of the process data

  1. Enhanced Biomethane Conversion and Microbial Community Shift Using Anaerobic/Mesophilic Co-Digestion of Dragon Fruit Peel and Chicken Manure
  2. Biochemical methane potential and biodegradability of complex organic substrates
  3. Bio-energy conversion performance, biodegradability, and kinetic analysis of different fruit residues during discontinuous anaerobic digestion
  4. Potential Biogas Production Generated by Mono- and Co-digestion of Food Waste and Fruit Waste (Durian Shell, Dragon Fruit and Pineapple Peel) in Different Mixture Ratio under Anaerobic Condition
  5. Improvement of fruit and vegetable waste anaerobic digestion performance and stability with co-substrates addition
  6. Effects of size and thermophilic pre-hydrolysis of banana peel during anaerobic digestion, and biomethanation potential of key tropical fruit wastes
  7. Effect of particle size on biogas generation from biomass residues

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

What it is and where it comes from

Pitaya, known as dragon fruit (Hylocereus spp.), is grown mainly in South-East Asia, Central America and Israel. The peel makes up a considerable part of the mass of the fruit and ends up as waste during the production of juices and preserves or on consumption. In Poland the fruit is imported and used marginally, so the material is significant mainly in analyses from the literature.

Properties relevant to digestion

The peel contains water, pectins and mucilages, which give it a gelatinous structure, and also cellulose, hemicellulose and a certain amount of lignin. It contains betalain pigments, which at typical doses are not a significant inhibitor. The content of simple sugars is lower than in the pulp, so the risk of rapid acidification is moderate, although pectins break down quickly. The high content of water and mucilage makes it harder to thicken and store the material, and spoilage occurs quickly.

How to read the spread of results

Records from several studies show an extremely large spread, and the deviation is comparable with the mean value. One of the studies gives the result in ml/g VS without explicit normalisation, and another is a control sample in which the peels were dried at 80 °C, which may have changed the composition (loss of volatile compounds, changes in structure). To these differences are added the species and variety of pitaya, ripeness, the amount of pulp remaining on the peel, chopping, inoculum and test conditions. For these reasons, the figures from the literature for this substrate are indicative only.

In biogas plant practice

Pitaya peels can supplement the feed together with manure or other fruit wastes in growing regions, after chopping and in gradual doses. The material spoils quickly, so long storage is inadvisable. Because of the large discrepancies in the results, implementation requires your own BMP test of the local batch. In Poland the practical significance is small.

It is also worth remembering that drying samples at high temperature and various methods of preserving them change the chemical composition of the material, so results for fresh and dried peels should not be directly compared or averaged without comment.

If the peels come from a plant producing juice, it is worth checking whether they contain preservatives or residues of acids added in the process, because such additives can disturb the activity of microorganisms more than the plant material itself.

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

  1. Zhao, C.; Yan, H.; Liu, Y.; Huang, Y.; Zhang, R.; Chen, C.; Liu, G. (2016). Bio-energy conversion performance, biodegradability, and kinetic analysis of different fruit residues during discontinuous anaerobic digestion. Waste Management 52, 295–301. DOI: 10.1016/j.wasman.2016.03.028 DOI
  2. Muenmee, S.; Prasertboonyai, K. (2021). Potential Biogas Production Generated by Mono- and Co-digestion of Food Waste and Fruit Waste (Durian Shell, Dragon Fruit and Pineapple Peel) in Different Mixture Ratio under Anaerobic Condition. Environmental Research, Engineering and Management 77(1), 25–35. DOI: 10.5755/j01.erem.77.1.25234 DOI
  3. Zheng, X.; Liu, S.; Faisal, S.; Khan, A.; Danish, M.I.; Rehman, A.; Du, D. (2025). Enhanced Biomethane Conversion and Microbial Community Shift Using Anaerobic/Mesophilic Co-Digestion of Dragon Fruit Peel and Chicken Manure. Biology 15(1), 83. DOI: 10.3390/biology15010083 DOI

All sources of the site: bibliography.

Other substrates in the group “Fruit, vegetables and their residues”