(BBSRC CASE DTP) Biotechnological investigation of the biodiversity in spontaneous beer fermentation: mining the interplay between microbial community, environmental pressures and aroma profile of products

Mixed fermentation (beer fermented with a variety of yeast species) was once the standard practise in the UK, but demanding brewing science and modern equipment made single species fermentation the modern norm. The craft brewing sector is now keen to re-discover the spontaneous mixed fermentation and to gain knowledge of the different airborne microorganisms present during the fermentation and how the composition of this microbial community changes according to the environment (i.e. seasonal variation, or different locations). In this project we are proposing two approaches: firstly we will study the microbial community and their evolution during spontaneous fermentation using a metagenomic approach. The composition of the community will be correlated with industrial trait of interests at the different stages of the fermentation (i.e. sugar contents, profile of the volatile organic compounds, etc.); secondly we will “spike” the initial wort with a different cocktail of barcoded traceable yeast species and hybrids, including the new discovered cold-tolerant isolate Saccharomyces jurei (ref 1). Here again we will follow the changes of the microbial community (including both the species introduced and the natural occurring microbes) via barcoded genome profiling (ref 2, 3) and metagenomic approaches. At every stage of the fermentation we will follow phenotypically the development of suitable industrial traits (flavour profile, cold-tolerance, sugar utilisation). The final goal of the project is to gain a better understanding of the key micro-organisms responsible for the desirable brewing traits, to investigate the effect of location and seasons on the microbial community, and to develop new protocols for spontaneous fermentation using new species and hybrids (including those discovered and developed in Delneri’s lab, ref 1, ref 4).
Our industrial partner, Cloudwater Brew are at the forefront of innovation in the UK craft brewing sector (ref 5, ref 6), and are keen to gain robust scientific principles to positively select microorganisms that produce excellent final products.