Turning horse manure into biomethane and lignin-based materials

Researchers at Université de Picardie Jules Verne used the Carousel 12 Plus Reaction Station across multiple stages of a new process designed to convert horse manure into renewable energy and higher-value biomaterials.

Horse manure is produced in large quantities and contains polysaccharides that can be converted into biomethane. However, the lignin naturally present in the material can restrict the accessibility of enzymes and microorganisms, limiting its potential for anaerobic digestion.

Researchers from the Génie Enzymatique et Cellulaire laboratory at Université de Picardie Jules Verne, working with colleagues from other university laboratories and analytical facilities, developed a new fractionation strategy known as Coffionic.

The aim was to separate horse manure into two useful fractions: a polysaccharide-rich material with improved potential for biomethane production, and a lignin fraction that could be converted into higher-value materials.

The Coffionic process combines an ionic liquid with a biodegradable, food-grade solvent and a naturally occurring amino acid catalyst. Following treatment, the horse manure was separated into a polysaccharide-rich solid and a lignin-rich liquid fraction.

The researchers also recovered and reused the solvent mixture across four fractionation cycles. The composition of the resulting fractions remained consistent, helping to demonstrate the potential for a lower-waste, closed-loop approach.

Overall, the process recovered 70% of the lignin present in the horse manure. The isolated lignin fraction had a purity of 78% and contained less than 2.5% residual sugars

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The Carousel 12 Plus Reaction Station was used at several stages of the study, allowing reactions to be carried out under controlled temperature and continuous magnetic stirring.

To assess the digestibility of the polysaccharide-rich fraction, enzymatic hydrolysis experiments were conducted at 50 °C for seven days. Samples were taken periodically to monitor the release of glucose and xylose.

The Carousel 12 was also used to carry out the enzymatic modification of the recovered lignin. These reactions were performed at 75 °C for 48 hours using an immobilised lipase and ethyl oleate. The modified lignin was subsequently combined with polylactic acid, or PLA, with the Carousel 12 used at 25 °C during preparation of the lignin–PLA mixtures.

Using the same reaction platform across these different stages provided the temperature range and stirring required for the enzymatic hydrolysis, lignin functionalisation and material preparation workflows.

The polysaccharide-rich fraction showed high enzymatic digestibility. Glucose release reached 75.8% after 48 hours, with more than 99% conversion achieved after seven days. Its biochemical methane potential was 17% higher than that of untreated horse manure.

The recovered lignin was then selectively modified through enzymatic transesterification. This modification improved its compatibility with PLA, allowing the researchers to produce flexible and homogeneous lignin–PLA films with altered surface properties.

Together, these findings demonstrate a route for obtaining both renewable energy and higher-value biomaterials from the same livestock waste stream.

This research demonstrates how the Carousel 12 can be used across diverse small-scale experimental workflows requiring consistent heating and magnetic stirring.

Capable of accommodating up to 12 reaction tubes, the Carousel 12 enables multiple reactions to be heated, stirred and refluxed simultaneously. In this study, it formed part of an integrated workflow spanning enzymatic biomass hydrolysis, lignin functionalisation and PLA–lignin material preparation.

Read the full research paper.

Discover the Carousel 12 Plus Reaction Station.

Figures reproduced from Dorschner Pelcoq et al., Bioresources and Bioproducts 2026, 2, 16, under the Creative Commons CC BY 4.0 licence.