Biorefining and cascading approach for mushroom residues and by-products

2018-10-18T09:05:53+00:00October 18th, 2018|

Introduction

The present document gives an overview of the achievements got during the development at bench scale of the cascade approach for the revalorisation of the mushrooms residues and by-products carried out in work package one.

The main Funguschain partners involved in the development and optimisation of the cascade approach are:

  • BioDetection Systems BV (BDS)
  • University of Alicante (UA)
  • Kungliga Tekniska Hoegskolan (KTH)
  • Neem Biotech Ltd. (NEEM)

Objective

The overall objective of WP1 was to develop suitable, scalable, cost effective methods to extract high value chemicals from a large volume waste material obtained from mushroom waste and encompassing the following items:

  • Cascading approach to obtain valuable chemicals and building blocks from mushroom waste.
  • Characterization of the potential functionalities of mushroom waste into high value chemicals.
  • Fractionation of the biomass using different treatment and intensification techniques.
  • Proposal of protocols for the appropriate treatment sequences (extraction, purification and functionalization).

Under this premise, UA, KTH, BDS and NEEM have been working together aiming to optimise the different extraction methods proposed when FUNGUSCHAIN was just an idea to get high valuable chemicals with functionalities that the end users of the project can incorporate into their products. These are food additives, cleaning products and biopolymers manufacturers.

The suggested process design for the valorisation of the different biomolecules from mushroom wastes integrates well-established and scalable technologies from biomass biotechnology in a cascade approach (Figure 1). These are simple processes that fully valorise all components all components of side streams:

Cascading approach of FUNGUSCHAIN

Cascading approach of FUNGUSCHAIN

Conclusions

Following the cascade approach suggested, the extraction techniques and the high value chemical extracted by each partner in WP1 are:

Partner Extraction technique used High value chemicals
NEEM Solid: Liquid extractions / Liquid:Liquid Extractions / Achiral Purification (Chromatography) Antimicrobials
UA Microwave-assisted extractions (MAE) Lipids and Polyphenols with antioxidant/antimicrobial properties.
KTH Pressurized hot-water extraction (PHWE) Soluble glucans
Fermentable sugars
Summary of extraction techniques and high value chemical obtained in the Cascade Approach

During WP1, partners have undertaken a joint research to design the most adequate processes for the extraction of all valuable products from mushroom by-products provided by MONAGHAN MUSHROOMS.

The extraction processes have been performed altering the source of raw material used and the respective process parameters.

Raw material: Mushroom waste from Monaghan

Raw material: Mushroom waste from Monaghan

All WP1 partners started processing the fresh waste material from Monaghan, in fresh and freeze dried conditions. This allowed determining the level of high value chemicals that could be obtained from each extraction technique.

Partners also interchanged the residues obtained from their processes with each other aiming to identify the high value chemicals that could be obtained in a second and third stage of the cascade extraction process.

The results from these tests helped to direct the theoretical best cascade approach.

As a result of the work carried out during the first 18 months of the Funguschain project, WP1 partners have developed three cascade approaches by combining different extraction protocols, such as Armfield (NEEM), Microwave Assisted Extraction (UA) and Subcritical Water Extraction (KTH).

To further characterise and valorise fractions obtained in the cascading process for high value applications, BDS has performed a human bioassay directed analysis to identification of fractions with nutraceutical applications. CALUX bio-assay-based methods were used for identification and purification of secondary fungal metabolites with medicinal and nutritional benefits from fungal residues, and fractions obtained in different extraction process. This work awaits further scale-up of the cascade to obtain sufficient material for further evaluation.

With the data generated from the three cascade approached, a decision needs to be made taking into account the technical and economic feasibility of the process on a pilot scale.

From the different extraction process performed in WP1, the following conclusions can be drawn:

Antimicrobials

  • The extract obtained at bench scale in the first step of the cascade approach using Armfield extraction process may have applications within cleaning products, which is one of the objectives of the Funguschain project. The co-operation with Saponia is ongoing to obtain further knowledge and potential applications of extracts within their current products.
  • Moreover, the extract may also have potential applications in the pharmaceutical field as a clinical antibiotic, assuming further physico-chemical tests to ensure its stability and other pre-requisites for drug development.

Polyphenols

  • MAE extracts showed the highest phenolic content and antioxidant activity of mushroom by-products, compared to other extraction processes, and all conditions and sample morphologies denoting the high efficiency of this method to extract these active compounds.

Lipids

  • The fatty acids (linoleic acid, oleic acid and palmitoleic acid) were successfully identified and quantified in the lipid extracts obtained from mushroom by-products.
  • The highest concentration of lipids was obtained after one step of MAE (at the optimized conditions) from lyophilised mushroom sample, followed by that obtained from the dried residue of MAE polyphenols extraction. Both materials showed their potential as a source of lipids.

Polysaccharides

  • Pressurized hot-water extraction was optimised in terms of extraction temperature, pH and extraction time for the isolation of soluble polysaccharides from the mushroom by-products. Successful extraction of polysaccharides was achieved with higher yields than traditional hot water and alkaline extraction.
  • Selective extraction of glucans can be achieved by controlling the extraction conditions.

Fermentable sugar

  • The saccharification of the mushroom by-products was evaluated using a 1-step and a 2-step acid hydrolysis process. The hydrolysis temperature, time and concentration of acid were optimized in terms of reducing sugars and released sugars.
  • The fermentable sugars were successfully tested for microbial growth and the production of biopolyesters by FUNGUSCHAIN partner Biotrend.

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