Yeastcell

Unlocking the potential of yeast Yeast has provided us with food and drink for thousands of years, and new research will enable yeast to provide valuable compounds for a sustainable society. We spoke to Dr John Morrissey and Dr Jan-Maarten Geertman about the lasting impact of EU-funded projects on yeast biotechnology Yeast has provided humankind with food and drink for thousands of years, now new research is going to enable yeast to provide valuable compounds for a sustainable society. Yeasts are widely used in biotechnology to produce a range of valuable items, from biofuels to flavours and from insulin to anti-aging products.

There is huge potential to expand this research in Europe and open up opportunities to use yeast to make more products quickly, efficiently, and sustainably.

Imagine taking a sip of your favourite wine or beer, or a scoop of your favourite ice cream. Maybe you have never given much thought to why one Sauvignon Blanc tastes different to another, what separates ale from lager, or where the flavours in your ice cream originate.

However, for people working in the food and beverage industries, getting the flavours just right for the consumer is critical. Products must remain consistent in quality and price in spite of weather events, climate change, seasonal availability of ingredients and many other variables. Consumers also want innovation without compromising on sustainability.

Recent research, funded by the European Union (EU), is focussing on yeast biotechnology to solve some of these problems in an economically and environmentally sustainable way. This was a major goal of the YEASTCELL training network. “The research focus of YEASTCELL was two-fold. On one side there were beverage yeasts, and on the other there were yeasts for industrial biotechnology,” explains Dr John Morrissey, who coordinated the project from University College Cork. “The emphasis was on understanding the kinds of yeasts that are used for fermented beverages, namely beer, wine and cider, and also on using modern technologies to create new yeast strains for a range of industrial applications. The research outcomes from YEASTCELL have been embraced by industry and inspired two new projects funded under the EU’s 10

Horizon 2020 programme, YEASTDOC and CHASSY, that will lead to further innovative solutions to pressing challenges facing European companies.”

Better Beverages: New Yeasts for Beer, Wine and Cider Brewers are particularly interested in using knowledge of yeast genetics and metabolism to diversify their product ranges and offer beers with new flavours that satisfy consumer desires. The yeast used to make modern lager (Saccharomyces pastorianus) is a hybrid - the result of a natural crossing of the standard yeast used for brewing ale and baking bread, Saccharomyces cerevisiae, and a ‘wild’ yeast, Saccharomyces eubayanus. Although the two yeasts originally crossed in the 15th century, the wild parent was not identified until 2011, when S. eubayanus was found in Patagonia, Argentina.

The discovery of this species has created new opportunities for the beverage industry. “It opened up the possibility of crossing these two species to make new hybrids with different traits,” outlines Dr Morrissey. Several academic partners in the project did exactly this and crossed ale yeasts with S. eubayanus to create new

yeasts for producing fermented beverages.

One of the partners in the project, HEINEKEN, are very interested in the potential of these new yeasts. “We aim to better understand these hybrid yeasts.

Different partners have been working to identify the traits in yeast that affect the characteristic flavours of beer,” says Dr Jan-Maarten Geertman, Manager of Product and Process Research at HEINEKEN. PhD researchers from the project worked with HEINEKEN to make beer and cider using their new yeast strains. These drinks had unique flavours and were very positively evaluated in a large-scale sensory trial. The new strains could be commercialised, and they serve as proof of principle for further strain development.

Companies that produce fermented beverages are aware of the need for sustainability, especially relating to the efficiency of their processes. Indeed, several projects in YEASTCELL explored ways to encourage yeast to perform more efficiently during fermentation of either wine or beer. Wine fermentation is actually a very stressful process for yeast, where it has to deal with low availability of some nutrients at the same time as

Dr Morrissey in University College Cork, Ireland.

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Ângela Carvalho was one of 11 Early Stage Researchers who received PhD training in the YEASTCELL network.

We spoke to her about her research and the benefits of working with both academic and commercial partners.

EU Research: Why was your research important?

Dr Ângela Carvalho: In recent years, the use of

EUR: What were the main technical challenges?

Dr Carvalho: We were trying to create a metabolic pathway,

medicinal Cannabis has increased globally, and legislation in many countries is becoming more liberal.

However, there are still problems with legalising cultivation of Cannabis in most countries, and attempts to make synthetic versions using chemistry did not prove to be an effective alternative because of high production costs and low yields obtained. We wanted to modify yeast cells to create a cost-effective, environmentally friendly, reliable supply of high-quality medicinal cannabinoids.

the stages that a cell goes through to produce a compound, and there was one part that we couldn’t figure out.

Fortunately, one of the other partners in the YEASTCELL project knew how to do it, so I spent some time with them learning how to do it.

EUR: How did you do this?

Dr Carvalho: We studied the literature available on Cannabis plant to identify the genes that are involved in producing different cannabinoid compounds. We then introduced these genes into yeast. It’s not that simple, though. On top of that, to produce the compounds we wanted, we also had to change the metabolism of the yeast. When you modify yeast to produce more of a certain compound, you have to make other changes to support this production.

strong osmotic pressure from the high concentration of sugar. A collaboration between INRA (France) and the wine yeast company Lallemand used the power of evolution to select yeast strains that were more efficient at wine fermentation under these conditions.

“Our partners, Lallemand, carried out some very interesting research using a method called laboratory evolution to select new strains of yeast,” Dr Morrissey explains.

This process makes use of the natural variation that occurs as yeast cells grow and divide. Researchers apply certain pressures and then identify variant yeasts that are able to withstand the stresses imposed by wine fermentation. These strains are then further analysed to identify the ones most suitable for largescale wine production. According to Dr Morrissey, this work can have even broader applications. “These approaches can help the wine industry select yeasts to cope with some of the negative effects of climate change on wine quality,” he says.

The problem is that rising temperatures are causing grapes in wine-producing areas to have increased levels of sugar.

This, in turn, causes an increase in the alcohol content of the wine to unacceptable

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EUR: You worked with academic and industrial partners, did they have different approaches to research?

Dr Carvalho: Yes, the perspective is different. In academia, you are often just focussed on a small part of the work. You are just trying to figure out a specific mechanism, for example. In industry, you might work on a product, so you can see the whole process and the wider benefit. For me, it was very important to be able to see the bigger picture.

EU Researcher: What are your plans for the future?

Dr Carvalho: I want to carry on working in synthetic biology in the future. I want to continue to use organisms to produce important products, or to discover new compounds.

levels. The challenge is to reduce the amount of alcohol in the wine without having a negative effect on the flavour profile. A follow-on project, YEASTDOC, will further address this challenge.

This new science is adapting traditional yeast fermentation.

A Fermented Future for Sustainable and Natural Ingredients Developing a sustainable society means finding new ways of making common consumer goods. Petrochemicals are the source of a large array of products, for example, flavours, aromas, cosmetics and plastics.

Plant-based or ‘natural’ ingredients are often marketed as safe alternatives to these ‘man-made’ chemicals

in cleaning products, foods, healthcare products, cosmetics, insecticides, and many other everyday items. However, extracting active ingredients from plants is not necessarily a greener or safer option - at a large scale, extraction can be expensive, unreliable, environmentally damaging, and even impossible.

The second major focus of the YEASTCELL research project was to investigate the potential to use yeast as a viable alternative to plant extraction or petrochemicals in biotechnology. There was special interest in the sustainable production of wax esters and fatty acids, which are commonly used in a range of cosmetics, personal care products, and other commercial applications. Currently, many of these ingredients are either synthesised from petrochemicals, or are extremely expensive or difficult to source.

Creating alternative industrial processes is a priority for the EU, and Dr Morrissey and his colleagues are addressing this. “We are looking at yeast to produce many highvalue molecules. This is not only cheaper than using petrochemicals, there are also benefits in terms of sustainability,” he says.

For example, you may be familiar with cosmetics and personal care products

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At a glance Projects YEASTCELL was a training network of partners from 8 European countries. 11 researchers worked towards their PhDs in topics that ranged from basic research into yeast cell biology to manipulating yeasts for industrial applications in the nutrition, beverage, and chemical sectors. YEASTCELL received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/2007-2013/ under REA grant agreement n° 606795.

YEASTDOC is a European Joint Doctorate network that will train 12 PhD candidates to apply modern genetics to enhance the performance of yeasts for industrial fermentation. They will also develop methodologies to improve yeast strains for novel applications in the fermented beverage industry.

YEASTDOC has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 764927.

CHASSY is an academia-industry research partnership focussed on designing chassis yeast strains that can be used as platforms for the production of a range of high-value compounds.

CHASSY has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 720824.

Contact Details Project Coordinator, Dr John Morrissey School of Microbiology University College Cork Cork, T12YN60, Ireland T: +353 21 490 2392 E: j.morrissey@ucc.ie W: www.yeastcell.eu W: www.yeastdoc.eu @YeastdocEU W: www.chassy.eu @ChassyProject

Dr John Morrissey

Dr Jan-Maarten Geertman

containing jojoba. The wax esters that are extracted from the Simmondsia chinensis plant and marketed as jojoba are used in lubricants and coatings, as well as in creams and conditioners. However, the cost of extracting the wax esters from the plant, and the limited number of areas in which it is grown, constrain production of jojoba extracts. Researchers in YEASTCELL succeeded in using yeast to biosynthesise jojoba-like wax esters, as well as other molecules that can replace petrochemicals in consumer products. The challenge for the research teams now is to move from proof-of-principle and prototype yeasts, to industrial yeast strains that are as efficient at producing valuable products as brewer’s yeast is at producing beer.

Zygosaccharomyces bailii. “The reason that we work on those yeasts is that they have properties, like thermo-tolerance and acid-tolerance, that are very useful for industrial production. By contrast, brewers yeast does not have these properties,” explains Dr Morrissey.

Researchers are building a deeper understanding of the genetic basis of these properties, and are investigating whether they could be introduced into S. cerevisiae.

CHASSY is a collaborative academiaindustry project that aims to support the European biotechnology sector. This project aims to move research along the pipeline from the lab and closer to commercial production. “CHASSY will focus on using yeast to produce aromatic molecules and

The focus was on understanding the kinds of yeasts that are used for fermented beverages, namely beer, wine and cider, and also on using modern technologies to create new yeast strains that might have interesting new applications Researchers built these prototype strains by reprogramming yeast, which involves finding relevant genes from different plants, yeasts and bacteria and assembling them in a particular order in a yeast strain.

“We then have a new yeast, which is capable of producing a molecule that it previously wasn’t able to produce,” outlines Dr Morrissey. This process is likened to traditional fermentation – where yeast uses sugars to produce ethanol and flavours in a beverage like wine or beer – only with a strain that has been programmed to produce the target compounds.

The industrial side of the research also has a focus on alternative yeasts such as Kluyveromyces marxianus and

oils,” says Dr Morrissey. “We are interested in taking some of the yeasts we already work with, for example, S. cerevisiae, K. marxianus and Yarrowia lipolytica, and engineering them for industrial production.” This will not be straightforward. “There is a very big gap between a proof-of-concept strain that is able to produce a small amount of an interesting compound, and a strain that can do this in an industrial setting and produce enough to be commercially viable,” stresses Dr Morrissey.

CHASSY aims to address this issue by optimising yeast strains and achieving commercial viability for the production of a wide range of molecules that you might find in your hand cream, your vitamin pills, your medicines, and even in your food.

Dr John Morrissey is a Senior Lecturer in microbiology at University College Cork. He has led his research group of postgraduate and postdoctoral scientists working in microbial ecology, microbe-host interactions and yeast biotechnology since 2003.

Jan-Maarten Geertman is Senior Manager Product & Process Research in HEINEKEN’s Global Innovation & Research department.

Current initiatives include optimizing the sustainability of yeast and associated fermentation processes, as well as the development of novel products.

Noemi Montini and Valentina Sforza in the Yeast Research Lab in University College Cork.

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