Profile: BIOrescue project – Making the most of wastes from mushroom production

Type of post: PROJECT PROFILE.

Two years ago, the Blog reported the launching of a BBI JU project focused on developing and demonstrating a new innovative biorefinery concept to valorize a waste from mushroom production: the Spent Mushroom Substrate (SMS). The name of this project is BIOrescue and was born from an encounter between one of the world’s largest mushroom producer (Monaghan Mushrooms) and Europe’s bioeconomy research community. In order to make this new concept a reality, several partners from eight countries under CENER (the National Renewable Energy Centre of Spain) coordination are cooperating to transform used mushroom compost into sustainable biobased products.

Related post: “Launch of European project leaded by CENER to develop a biorefinery concept based on mushroom residues”, 3/10/2016.

On 11th October 2018, the consortium organized a workshop (“Towards a circular bioeconomy in Spanish industry”) to share the results of the project and discuss opportunities to close the loop in the Spanish bioeconomy sector. I had the opportunity of attending this event which was held in Madrid and learning first-hand about the smart BIOrescue concept. The following lines are a summary of the presentations focused on explaining this new biorefinery model.

The challenge

Each year, over 3 million tons of mushroom compost is generated by mushroom production, thus creating significant economic and logistical problems for Europe’s farmers. This compost, prepared solely for growing mushrooms from chicken manure, peat and wheat straw, is only suitable for one to three harvests. The mushroom industry lacks adapted technological solutions to upgrade this spent compost into valuable products.

Figure 1. The compost, prepared solely for growing mushrooms, is only suitable for one to three harvests (extracted from “Creating value from agricultural residues: the biorefinery process step by step” presented on the workshop by Inés del Campo from CENER)

SMS contains significant amounts of lignin but relatively low concentrations of cellulose and hemicellulose. The project also targets the supplementation of additional underutilised feedstocks that can improve the composition of a mix containing SMS. Wheat straw has been selected as one supplementary feedstock due to its attractive cellulose content and its current use within existing mushroom farm infrastructure. Other feedstocks are being examined to check their suitable for co-feeding with SMS in the configured process scheme of the BIOrescue conversion technologies: prunings from a number of crops (olive trees, vineyards, almond trees and peach trees), pomace samples from olives and grapes, sugar beet pulp…

The biorefinery model

The BIOrescue project aims to develop and demonstrate a new innovative biorefinery concept based on the cascading use of SMS according to the diagram flow shown in the Figure 2. It is comprised by three main stages: fractionation, primary conversion and secondary conversion.

Figure 2. BIOrescue biorefinery concept (extracted from “Creating value from agricultural residues: the biorefinery process step by step” presented on the workshop by Inés del Campo from CENER)

Fractionation

The concept includes a two-step fractionation process for mushroom compost:

(1) Solid-liquid extraction of high added value components;

(2) Thermochemical pretreatment process that aims to fractionate the SMS into different components that can be subsequently transformed into valuable biobased products.

Primary conversion

The primary conversion is an enzymatic hydrolysis stage that includes enzyme immobilisation and recycling. The Finnish company MetGen has utilised its MetZyme® SUNO™ enzyme solution tailored for specific biomass and process conditions to significantly improve saccharification yields at high dry solid content and reduce cost through lower enzyme dosage. In addition, the University of Naples Federico II is developing new enzymes using genetic evolution to further increase process performance.

Secondary conversion

The secondary conversion technologies target the subsequent transformation of the fraction obtained from SMS: cellulose to biopesticides and enzymes and the lignin and hemicellulose into nanocarriers.

The bioproducts

Biopesticides

Biopesticides are organism or substances derived from natural materials (such animals, plants, bacteria or certain minerals), including their genes or metabolites, for controlling pests. In this project, the biopesticide is obtained by Bacillus thuringiensis HD1. This organism produces proteins (Crys) which are characterised by their: high specificity, lability and biodegradability. The hydrolysate derived from the mix of SMS and wheat straw is used as carbon source in the fermentation broth.

Nanocarriers

One of the objectives of BIOrescue activities is the formulation of lignin-nano/microcarriers by miniemulsion, their loading with drugs (among them, the aforementioned biopesticides) and their upscaled production. The building blocks for those carriers come from SMS: carbohydrates and lignin.

Figure 3. The building blocks for nanocarriers come from SMS (extracted from “Biodegradable nanocarriers for targeted plant treatment” presented on the workshop by Frederik Wurm from Max Planck Institute for Polymer Research)

The Max Planck Institute for Polymer Research is developing the natural polymer membranes to create those biodegradable nanocapsules that enable the progressive and controlled release of the drugs. It is the adaptation of a proven medical concept that could reduce drastically the waste of chemicals occurring during pesticide spraying as well as allow the direct delivery of the drugs in internal parts of the plant.

Figure 4. Injection of lignin nanocarriers (extracted from “Biodegradable nanocarriers for targeted plant treatment” presented on the workshop by Frederik Wurm from Max Planck Institute for Polymer Research)

Other activities

- Celignis is developing customised mathematical models to predict the composition of samples related to the conversion processes studied during the project.

- C-TECH is leading all exploitation activities and perform the economic analysis, ensuring market uptake for the newly developed biobased products and the most promising innovations of the project.

- Greenovate! Europe is disseminating information about the project and its achievements as well as preparing the exploitation of the project’s results.

- Imperial College London is performing the sustainability assessment of the project covering techno-economic performance, environmental, social and political issues.

- Zabala is managing all administrative and financial aspects of the project.