Sugar-seeking insects as a source of diverse bread-making yeasts with enhanced attributes.

Abstract

Insects represent a particularly interesting habitat in which to search for novel yeasts of value to industry. Insect-associated yeasts have the potential to have traits relevant to modern food and beverage production due to insect-yeast interactions, with such traits including diverse carbohydrate metabolisms, high sugar tolerance, and general stress tolerance. Here, we consider the potential value of insect-associated yeasts in the specific context of baking. We isolated 63 yeast strains from 13 species of hymenoptera from the United States, representing 37 yeast species from 14 genera. Screening for the ability to ferment maltose, a sugar important for bread production, resulted in the identification of 13 strains of Candida, Lachancea, and Pichia species. We assessed their ability to leaven dough. All strains produced baked loaves comparable to a commercial baking strain of Saccharomyces cerevisiae. The same 13 strains were also grown under various sugar and salt conditions relevant to osmotic challenges experienced in the manufacturing processes and the production of sweet dough. We show that many of these yeast strains, most notably strains of Lachancea species, grow at a similar or higher rate and population size as commercial baker's yeast. We additionally assessed the comparative phenotypes and genetics of insect-associated S.cerevisiae strains unable to ferment maltose and identified baking-relevant traits, including variations in the HOG1 signaling pathway and diverse carbohydrate metabolisms. Our results suggest that non-conventional yeasts have high potential for baking and, more generally, showcase the success of bioprospecting in insects for identifying yeasts relevant for industrial uses.