FRUTALGA demonstrates the potential of advanced technologies to transform fruit waste into renewable energy and extracts for cosmetics.

FRUTALGA has demonstrated the potential of advanced technologies to transform fruit waste into high value-added ingredients. The project has combined renewable energy generation with the production of natural extracts for cosmetic applications and microalgal biomass with potential for other industrial applications.

The FRUTALGA project, funded by the Agència Valenciana de la Innovació (AVI), has been developed by AINIA, which leads the design and development of the technological processes (anaerobic digestion, bioproduction, supercritical CO₂ extraction); AVA-ASAJA, responsible for the supply and pre-treatment of fruit waste; SITRA, specialised in the design, commissioning and operation of the reactor for pilot-scale mixed culture trials; IDiBE, focused on the identification and characterisation of bioactive compounds; and Prospera Biotech, responsible for the design, formulation and validation of the efficacy of a premium final cosmetic product.

From fruit waste to energy: anaerobic digestion integrated into the process

Using fruit waste generated during processing operations, the project has developed an anaerobic digestion system designed to produce an alternative energy source using exclusively the substrates obtained במסגרת the project. This process makes it possible to generate 28 m³ of methane for every tonne treated, contributing to energy self-sufficiency and to the overall sustainability of the model.

Pilot- and pre-industrial-scale microalgae for new applications

Based on the characterisation of different fruit juices, a pilot reactor was designed and validated to test, under controlled conditions, the joint cultivation of microalgae and bacteria. To this end, the most suitable fruits were selected, pre-treatment was validated and the physicochemical properties of the juices obtained were analysed. The trials were carried out in the raceway-type reactor installed at AVA-ASAJA’s Finca Sinyent, where parameters such as pH, dissolved oxygen, suspended solids, turbidity and nutrients (N, P and K) were monitored. The biomass generated was harvested for subsequent characterisation, which has made it possible to assess its potential as a value-added product.

In addition, mixed microalgae-bacteria cultures were generated in the laboratory using different liquid fractions, with orange juice selected as the most suitable. In parallel, growth conditions for three microalgae species were selected and optimised at different scales (laboratory, pilot and pre-industrial), in closed and open photobioreactors, with and without the addition of orange juice. These conditions were extrapolated to pre-industrial scale, achieving sustained production of tens of dry kilos of two selected microalgae for the production of compounds of interest for cosmetics. In addition, pilot-scale samples from the microalgae-bacteria culture were nutritionally analysed and their use as an ingredient for animal feed was validated.

Supercritical CO₂ extracts and premium cosmetic formulation

The research has made it possible to develop green processes based on supercritical CO₂ extraction through the application of different process alternatives — including extraction with modifiers and pressurised liquid extraction — to obtain extracts from fruit by-products and/or microalgal biomasses. These extracts show biological activities of potential interest for cosmetic products, supported by the characterisations carried out within the framework of the project.

Specifically, extracts from avocado stone, date stone and microalgae stand out for their potential antioxidant, depigmenting and healing activity. Extracts with potential capacity to modulate TRPA1 have also been identified. TRPA1 is a protein present in nerve endings and some skin cells that acts as a “sensor” to certain stimuli, such as irritants or environmental changes, and is linked to skin sensitivity and comfort responses.

At the application stage, following the safety and biological activity assessment carried out, a cosmetic has been designed and formulated that combines the selected extracts with other active ingredients, aimed at the care of mature and sensitive skin prone to hyperpigmentation and photoaging. The result is a premium cosmetic product, opening the door to future industrial scale-up and commercialisation phases.

Additionally, within the framework of the project, the equivalent CO₂ emissions (CO₂eq) of the proposed valorisation model have also been calculated, taking into account the emissions avoided through the production of co-products such as heat, electricity and organic fertiliser, and comparing the reduction in emissions against conventional alternatives.

The results of FRUTALGA consolidate an advanced technology model applicable to the fruit and biotechnology industries, capable of converting by-products into new ingredients and renewable energy. This approach helps reduce waste and drive more sustainable solutions for sectors such as cosmetics and animal feed.