Artur Rego-Costa

Yeast evolutionary dynamics in large industrial bioethanol fermenters

Artur Rego-Costa, Graduate Student in Organismic and Evolutionary Biology, Desai Lab, Harvard

Bioethanol production in Brazil uses yeast (S. cerevisiae) to ferment sugarcane products in large fermentors that hold population sizes as large as 1017 individuals. The yeast population gets recycled at every fermentation cycle through the course of the eight-month long fermentation season. We sampled whole populations at two different plants, over the course of two fermentation seasons, and used a combination of metagenomics and whole-genome sequencing to infer lineages of descent and their frequencies through time in these highly diverse (>100k SNPs) non-haploid populations. We find that population dynamics is dominated by competition between industrial starter strains, and foreign ones, and that this dynamics seems unrelated to fluctuations in fermentation metrics.