Optimisation of the Quorn fermentation process for the production and extraction of functional mycoprotein

Lead Research Organisation: Heriot-Watt University
Department Name: Sch of Energy, Geosci, Infrast & Society

Abstract

This project proposes to assess the technical and commercial feasibility of producing and extracting functional mycoprotein from the Quorn fermentation process. This process is based on the conversion of starch into protein by the fungus Fusarium venenatum. The resulting mycoprotein is currently solely used for the production of Quorn's food products. However a current collaboration between Heriot-Watt University (HWU) and the company showed that mycoprotein extracted from the fermented broth on a laboratory scale displayed outstanding foaming, emulsifying and gelling properties, highlighting their potential use as commercial functional proteins.

There is a need to develop valuable and sustainable functional proteins for the food industry. Indeed animal-based sources of proteins such as whey or egg are responsible with high greenhouse gas emissions. Similarly, the costs and environmental impact of functional delivery systems for drugs and bioactive compounds often hinder their commercialisation. On the contrary, Quorn's industrial processes reported 90% lower emission rates of greenhouse gas emissions and benefits on land and water footprints in comparison with beef products. The idea behind this project is to assess the development of functional mycoprotein as sustainable protein replacements for the industry.

The funding received will allow first to design and assess a mycoprotein extraction process according to protein purity, yield, functionality, composition and associated costs. The results obtained will then be used to investigate the technical and economic feasibility of optimising the Quorn fermentation process for functional protein production on a large scale.

In a first stage, a range of protein separation and purification methods will be screened in Nicholas Willoughby's laboratory. In parallel the composition and functionality of the resulting extracts will be characterised in Stephen Euston's laboratory. Based on this screening a protein extraction strategy will be designed and further optimised, while its economic impact will be assessed by Quorn.
Based on these results, the company will assess the viability of optimising its fermentation process to specifically produce functional mycoprotein. An adapted fermentation process with first be designed and optimised on a laboratory scale, followed by a series of scaled-up pilot trials. In parallel the composition and functionality profile of the resulting proteins will be monitored, as well as associated costs.

A number of economic, environmental and societal benefits would arise from this project. This research could pave the way for the development of sustainable functional mycoproteins for the food industry. Based on preliminary work it is estimated that up to 13,500 tons of mycoprotein (at 80% protein purity) could be produced per year. Based on current prices, this production could open up a market worth £78M per annum. In addition the extraction of functional mycoprotein from Quorn's main co-product would further reduce the company's environmental impact while opening up an additional market of up to £14M per year.

This project will contribute to improve quality of life by offering manufacturers cost-effective functional protein alternatives, allowing them to offer cheaper products to the benefit of consumers. In addition, preliminary results indicate that functional mycoprotein could act as fat replacer due to unique foaming and emulsifying properties, so could contribute to the reduction of obesity. This collaborative project will allow Quorn to access specific multidisciplinary expertise developed at HWU in protein extraction and characterisation. The partnership with Quorn will help establish Heriot-Watt University as a major Scottish and UK centre for sustainable protein production, and should lead to many years of collaborative research outwith this project.

Technical Summary

Proteins are used as functional ingredients in a wide range of manufactured foods. In addition to their nutritional properties, proteins are excellent emulsifying, foaming and gelling agents and contribute to the structure and stability of formulated foods through these properties. Animal proteins (egg, milk) are popular due to their superior functional properties over plant proteins (soy, wheat). However, the sustainability of animal protein production is continually under scrutiny and alternative non-animal sources of protein with adequate functionality are being sought to overcome this issue. Quorn is a mycoprotein based meat replacer that has been shown to have excellent sustainability credentials. Our previous work has demonstrated that a functional mycoprotein product can be prepared from the leftover fermentation broth after separation of the fungal biomass used for Quorn production. The waste broth contains extracellular proteins expressed by the fungi, as well as proteins from the cell membrane disrupted during mycelia separation. When concentrated and dried, the protein powder has excellent emulsifying and foaming properties over and above comparable animal protein products. The current project will progress this work in a number of areas. Firstly, we will assess a number of separation and purification methods for their technical and economic suitability for production of high purity mycoprotein powders. Secondly, these processes will be assessed for their suitability for scale-up production of protein. Finally, we will assess the feasibility of fractionating the mycoprotein in to different protein classes to assess whether further functional diversification of the protein can be achieved. In parallel to this, Quorn will work on the control of the fermentation process to ascertain whether it is possible to manipulate the composition of the left-over fermentation broth to produce higher proportions of functional exo-proteins.

Publications


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Description The waste stream form the Quorn fermentation process is a source of proteins that have been shown to have interesting functional properties as food molecules. These include emulsifying, foaming and gelation properties. If these proteins are to be exploited as food ingredients we have to develop an economical process to extract the proteins. In addition, we have to demonstrate that proteins found in the waste stream have consistent properties throughout the 32 days of a typical fermentation cycle. The research at Heriot-watt University (HWU) has taken two parallel paths. Firstly, we have tracked the Quorn production cycle, and tested protein isolated from the waste stream at various times during that cycle. Results indicate that once the cycle has reached the continuous growth phase, both the protein content and functional properties are relatively stable, and thus can be continuously processed to yield functional protein. Marlow Foods (MF) the manufacturers of Quorn have also carried out fermentation cycles where various process variables have been altered to ascertain the effect this has on protein content and functionality of the waste stream proteins. These included changes to the cell dry mass at which the fermenter is operated and changes in temperature of various process stages. These had little effect on the protein compostion of the waste stream nor on the funcitonal properties and we concluded that the fermentation process is already runing under optimum conditions. High pressure homogenization (HPH) of the waste stream was also tried in an attempt to free protein from the cell debris present. HPH was found to have a negative impact on functional properties of the protein, possibly due to release of cell components that interfere with protein adsorption to oil-water (emulsions) and air-water (foam) interface (possibly membrane lipids). The conclusion from this work was that the Quorn waste stream is a source of proteins that have the potential to be added to foods as a fucnitonal ingredient (foming, emulsifcation or gelling ingredient). This project laid the foundation for a further successful application to Innovate UK for a follow on project that is reported separately.
The second research track involved an assessment of the best methods for extracting protein from the waste stream. Various methods such as solvent precipitation (acid, alkali), ammonium sulphate (NH2SO4) precipitation, ion exchange chromatography, hydrophohic interaction chromatography, tangential cross flow filtration, foam fractionation, freeze-thaw fractionation, nanofiltration, freeze-concentration, and affinity flocculation were tried. Solvent precipiation gave poor recovery of protein and was discontinued. NH2SO4 precipitation gave good recovery of protein, with no evidence of differential fractionation, but required very high concentrations of NH2SO4 which was carried over into the dried protein product. Desalting techniques were tried to optimize this method but were expensive. We concluded that the high addition of salt needed made this method economically non-viable and this was discontinued. Hydrophobic interaction chromatography gave good separation of proteins, but the fractions had poor functionality. Due to the hgh cost of HIC resins, and the poor funcitonality of the fractions, this was discontinued. Ion-exhange chromatography proved very difficult, possibly due to the presence of charged contaminants that stick to the resin. This was discontinued.
Tangential cross flow filtration, foam fractionation, freeze-thaw fractionation and nanofiltration all proved promising for concentrating the protein and were taken forward to prepare gram quantities of fungal protein extracts for further assessment of funcitonal properties in a follow on project. Free-concentration and affinity precipitation were two methods carried out a third party companies. Samples of these proteins will be included in those samples assessed in the follow on project.
Exploitation Route We already have a follow on Innovate UK project which will take the findings from this project and exploit them in two ways.
(1) development of a process for the extraction of functional mycoprotein from the Quorn process.
(2) development of proof of principle food products through industrial end users in the food industry that exploit the functional properties of the extracted mycoprotein.
Sectors Agriculture, Food and Drink,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology
 
Description Innovate UK CR& D
Amount £1,000,000 (GBP)
Funding ID IUK-50387-377177 and BB/N004957/1 (BBSRC Co-funding) 
Organisation Government of the UK 
Department Innovate UK
Sector Public
Country United Kingdom of Great Britain & Northern Ireland (UK)
Start 12/2015 
End 11/2018
 
Description MARISURF 
Organisation Marlow Foods
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Private 
PI Contribution MARISURF is a 4.8Meuro H2020 project coordinated by HWU to identify, isolate and purify biosurfactants from marine bacteria. The production will then be scaled up to pilot scale and the surfactants tested by industrial end-users from various industry sectors including food, cosmetic and biomedical sectors. My research group is responsible for overall coordination of the project, and specifically for the screening of functional properties of the surfactants to ensure suitability in industrial applications.
Collaborator Contribution Marlow Foods are a partner in MARISURF an EUH2020 project coordinated by HWU. They will test marine bacteria-derived surfactants in their Quorn food applications.
Impact The collaboration is multi-disciplinary and involves the following scientific disciplines, Microbiology Chemistry Biochemistry Molecular Biology Process Engineering
Start Year 2015
 
Description Bridge2Food Food proteins Conference paper 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation of research results at a industry/academic conference on sustainable production of food proteins. We presented our approach to separation isolation, and modulation of functionality of novel food proteins. The talk was well received by industry members of the audience and resulted in a number of inquiries about possible collaborations and/or consultancy work.
Year(s) Of Engagement Activity 2015
 
Description Food Colloids Conference, Wageningen The Netherlands 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Results presented at a major food colloids conference (sponsored by the Royal Society of Chemistry) held in Wageningen, The Netherlands in April 2016.
A poster was given on the computer simulation of olegelation by sterols and sterol esters, and on the functional properties of novel fungal proteins.
Year(s) Of Engagement Activity 2016
 
Description Interface Food and Drink reformulation Meeting at Strathpeffer Pavillion, Inverness 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Interface food and drink reformulation group is a working group set up by Interface, the academic-industry engagement body, that has the remit to facilitate collaboration between Scottish academics and the food industry in the area of food reformulation for improved health. I was invited to talk about our work on novel, sustainable proteins as animal protein replacers, and on fat replacement in foods.
Year(s) Of Engagement Activity 2015