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BMP testingAlgae and aquatic plantssingle study (3 samples)

Phaeodactylum tricornutum — BMP: 3 studies, weighted mean 299 m³ CH₄/t VS

Phaeodactylum tricornutum is a marine diatom, a model alga for research on lipids and fucoxanthin; the dataset contains several values from a single literature review.

CH₄ ≈ 58 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

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

Weighted mean
299m³ CH₄/t VS
Range
270–337m³ CH₄/t VS
Records
3single study (3 samples)
Publications
1source
Temperatures
33 °C, 35 °C, 54 °Cof the test

Methane in biogas

Medium methane content · ≈ 5.8 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (protein-rich (process classification)) 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: Phaeodactylum tricornutumCumulative methane production over time for 3 records and the weighted mean of 299 m³ CH₄/t VS. 3 of the curves are model curves (first-order kinetics).01002003004000510152025303540time [d]m³ CH₄/t VSJankowska et al. (2017) · 1: 270 m³ CH₄/t VS (model curve)Jankowska et al. (2017) · 2: 290 m³ CH₄/t VS (model curve)Jankowska et al. (2017) · 3: 337 m³ CH₄/t VS (model curve)mean299

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 (299); 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
Jankowska et al. (2017) · 1 DOI27033 °C · mesophilic(orig.: “Phaeodactylum tricornutum”): value quoted in a literature reviewend point (model curve)
Jankowska et al. (2017) · 2 DOI29054 °C · thermophilic(orig.: “Phaeodactylum tricornutum”): value quoted in a literature reviewend point (model curve)
Jankowska et al. (2017) · 3 DOI33735 °C · mesophilic(orig.: “Phaeodactylum tricornutum”): value quoted in a literature reviewend point (model curve)
Weighted mean299arithmetic mean 299, SD 34

Process properties

  • protein-rich
  • nitrogen-rich
  • saline
  • dilutes the feed (low DM)
  • variable composition
  • 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 290 (range 270–337) m³ CH₄/t VS, 3 records from 1 papers (weighted mean 299).

Drawbacks and risks

  • The high protein content of the cells causes release of ammonia, which can be toxic to the process (Sialve et al. (2009); Rajagopal et al. (2013))
  • The presence of sodium in marine species may impair digester operation (Sialve et al. (2009))

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

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

  • Do not dry the biomass before feeding: drying lowered biogas production to about 80% (Mussgnug et al. (2010))
  • Monitor ammonia (high protein) and, for marine species, sodium (Sialve et al. (2009))

Sources of the process data

  1. Anaerobic co-digestion of algal sludge and waste paper to produce methane
  2. Anaerobic digestion of microalgae as a necessary step to make microalgal biodiesel sustainable
  3. A critical review on inhibition of anaerobic digestion process by excess ammonia
  4. Biogas from microalgae: Review on microalgae's cultivation, harvesting and pretreatment for anaerobic digestion
  5. Microalgae as substrates for fermentative biogas production in a combined biorefinery concept

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

What it is and where it comes from

Phaeodactylum tricornutum is a unicellular marine diatom occurring in coastal waters. It is a model organism in diatom research: genetic tools have been developed for it, and its biomass contains lipids, including omega-3 fatty acids, and the pigment fucoxanthin. It is grown in photobioreactors. The dataset contains several values from one literature review, including tests at mesophilic temperature and one at thermophilic.

Properties relevant to digestion

Unlike most diatoms, which have a heavy siliceous shell, this species produces weakly silicified cells, which reduces the barrier to enzymes. The biomass contains lipids, protein and carbohydrates in proportions depending on the growing conditions. Lipids increase the methane potential, but in excess favour VFA inhibition. Protein may release ammonia, and the marine origin means possible presence of salt if the biomass was not washed. Diatoms may also contain silica, which does not degrade and ends up in the digestate.

How to read the spread of results

The records from one review differ in temperature and probably in strain or growing conditions. The variability of diatom biomass composition is large: it depends on the availability of nitrogen and silicon, light, the growth phase and the method of harvesting. The form of the sample (fresh suspension, freeze-dried), cell disruption, the substrate-to-inoculum ratio, the adaptation of the inoculum to salt and the length of the test also matter. With such a small dataset and a sparse description of conditions the results should be treated as indicative.

In biogas plant practice

Phaeodactylum tricornutum is not a biogas plant substrate; it is an interesting subject of research into the cascading use of algal biomass, where valuable compounds are obtained first and the residue is sent to digestion. In such an application salinity, ammonia and the presence of silica must be taken into account. Legal requirements depend on the origin of the biomass and the plant's permits; as a non-invasive organism grown under controlled conditions, it is not subject to special restrictions.

It is also worth noting that results from literature reviews are difficult to compare with each other without knowing the substrate-to-inoculum ratio, and in such compilations it is usually not given.

Given these limitations, a sensible practice is to run a BMP test of your own on the specific batch of biomass before taking technological decisions.

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 = 0.102 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. Jankowska, E.; Sahu, A.K.; Oleskowicz-Popiel, P. (2017). Biogas from microalgae: Review on microalgae's cultivation, harvesting and pretreatment for anaerobic digestion. Renewable and Sustainable Energy Reviews 75, 692–709. DOI: 10.1016/j.rser.2016.11.045 DOI

All sources of the site: bibliography.

Other substrates in the group “Algae and aquatic plants”