Biology subjects

Jahn, L. J.

Publications and source records attributed to Jahn, L. J..

3 recordsLinked to original sources

bioRxiv2024

Making yogurt with the ant holobiont uncovers bacteria, acids, and enzymes for food fermentation

Milk fermentation has a rich history in which food culture, the environment, and microbes intersect. However, the biocultural origins of fermentation practices and microbes have largely been replaced by industrial processes. Here, we consider a historical fermentation originating from Turkey and Bulgaria - ant yogurt. We revisit the traditional practices and modern gastronomic applications that use red wood ants (Formica rufa group) to initiate milk fermentation. Subsequently, we characterize the ants and experimental ant-derived yogurts. We uncover that the ant holobiont, which consists of the ants and their microbes, contributes key acids and enzymes to fermentation. Metabarcoding and culturing revealed that lactic and acetic acid bacteria, including species related to conventional sourdough, originate from the live ants and proliferate in the milk. The ants and bacteria consequently introduce formic, lactic, and acetic acid, advantageous for yogurt acidification and coagulation. Last, proteases with the potential to act on casein may alter yogurt texture and are produced by the ants and bacteria. The ant holobiont thus catalyses fermentation akin to the microbial consortia in other ferments. Our findings highlight the value of integrating traditional, gastronomic, and biological frameworks to uncover the origins and applications of microbes for fermented foods.

microbiology↗

bioRxiv2024

Food Fermentation in Space Is Possible, Distinctive, and Beneficial

Space exploration is expanding, which demands new technologies and enables new scientific questions. Food, as a bridge between disciplines, can bring these fundamental and applied goals together. Here we investigate whether food fermentation in space is possible, and if so, how it compares with fermentation on Earth. We fermented a miso, a traditional Japanese condiment, on the International Space Station over 30 days, and compared it with two earthbound controls. Using a specially-built environmental sensing box, we gathered metadata for temperature, relative humidity, pressure, and radiation. We analyzed the three misos with shotgun metagenomics to investigate the microbial communities composition and safety; whole genome sequencing to investigate the mutation rate of Aspergillus oryzae; untargeted metabolomics to quantify aromatic compounds, amino acids and organic acids; colorimetry to quantify color; and sensory analysis to describe the misos flavours and quantify liking and sensory difference. Across these datasets, we found that overall, the space miso is recognizable as a miso, suggesting fermentation in space is possible. We also found certain differences in the space miso: specifically the presence of Bacillus velezensis, a higher mutation rate of A. oryzae, higher attributions of roasted and nutty flavours, and the most different sensory impression. Taken together, these observations suggest unique features of the space environment--what we might call space terroir--which could be harnessed to create more flavorful, nourishing foods for long-term space missions and to address fundamental questions about the biology of novel environments. Significance StatementOur study presents, to our knowledge, the first time a food product has been fermented in space. We demonstrate that fermentation in space is possible with safe and successful results, a proof of concept that offers fermentation as a new tool for space research and future long-term space exploration missions. We also document how the space environment shapes the fermentation process in unique ways, suggesting a space terroir. These findings on the feasibility and novelty of fermentation in space open up directions for further multidisciplinary research across science, health, systems design, and society and culture.

microbiology↗

bioRxiv2023

Pangenome analysis reveals the genetic basis for taxonomic classification of the Lactobacillaceae family

Lactobacillaceae represent a large family of important microbes that are foundational to the food industry. Many genome sequences of Lactobacillaceae strains are now available, enabling us to conduct a comprehensive pangenome analysis of this family. We collected 3,591 high-quality genomes from public sources and found that: 1) they contained enough genomes for 26 species to perform a pangenomic analysis, 2) the normalized Heaps coefficient {lambda} (a measure of pangenome openness) was found to have an average value of 0.27 (ranging from 0.07-0.37), 3) the pangenome openness was correlated with the abundance and genomic location of transposons and mobilomes, 4) the pangenome for each species was divided into core, accessory, and rare genomes, that highlight the species-specific properties (such as motility and restriction-modification systems), 5) the pangenome of Lactiplantibacillus plantarum (which contained the highest number of genomes found amongst the 26 species studied) contained nine distinct phylogroups, and 6) genome mining revealed a richness of detected biosynthetic gene clusters, with functions ranging from antimicrobial and probiotic to food preservation, but [~]93% were of unknown function. This study provides the first in-depth comparative pangenomics analysis of the Lactobacillaceae family.

systems biology↗