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. Take Away• We isolated yeasts from insects, identifying 63 strains of yeast from 14 genera.• Maltose fermentation was variable among species and strains.• Non-Saccharomyces yeasts leavened bread comparable to baker's yeast.• Insect-associated yeasts exhibited high osmotolerance and halotolerance.• Hymenoptera are a source for bioprospecting yeast for baking.

Yeast–insect interactions in southern Africa: Tapping the diversity of yeasts for modern bioprocessing

“…However, brewing and baking might just be as old since no pure cultures were used, mostly back slopping. The currently used industrial yeast strains in bread and beer are arguably thought to be derived from ancestors of insect origin (Madden et al, 2022). Another important study postulates that insects were involved in the evolution and biodiversity of Saccharomyces yeasts (Stefanini et al, 2016).…”

“…and Vestipula spp. and Hanseniaspora F I G U R E 3 Ancient industries that could potentially be improved by use of insect-associated yeasts (de Melo Pereira et al, 2014;Gutiérrez et al, 2018;Madden et al, 2022;Makopa, Semumu, et al, 2023;Morata et al, 2018;Pérez et al, 2003;Schwan et al, 2023;Stefanini et al, 2012).…”

“…opuntiae from Chilo partellus exhibited unique aroma profile at pilot brewing scale (Madden et al, 2022;Makopa, Semumu, et al, 2023).…”

Saccharomyces yeast hybrids on the rise

“…We anticipate a significant expansion of the currently limited genomic resources for hybrids in the near future. A fruitful strategy to isolate more hybrid strains from the wild may be to target environments with extreme or fluctuating conditions (e.g., temperature, carbon source, or pH), such as insect guts (Madden et al, 2022; Stefanini, 2018; Sung‐Oui et al, 2005), which may be conducive for hybrid yeasts with novel resistance and metabolic phenotypes. The high prevalence of aneuploidies found in interspecific hybrids may further confer adaptation to extreme environments (outlined in Gilchrist & Stelkens, 2019).…”

Diversity of dung beetle‐associated yeasts from pristine environments of Botswana

“…It is not surprising that, to date, the most described and domesticated yeasts seem to have been derived from insect‐yeast associations. Examples of yeasts isolated from insects, whose applications in the industry are relevant include: Saccharomyces cerevisiae, Brettanomyces (= Dekkera ) anomala, Brettanomyces (= Dekkera ) bruxellensis , Torulaspora delbrueckii, Yarrowia lipolytica, Kluyveromyces marxianus , Ogataea polymorpha, Wickerhamomyces anomalus, Pichia kluyveri, Pichia kudriavzevii, Zygosaccharomyces rouxii , and Metschnikowia pulcherrima (Ba & Phillips, 1996; Madden et al, 2022; Nwaefuna et al, 2021; Sandhu & Waraich, 1985; Schäfer et al, 1996; Stefanini, 2018; Stefanini et al, 2012; Witzgall et al, 2012). Most of these yeasts were isolated from sugar‐seeking insects that forage on fruits, nectar, and honeydews.…”