Comparative genomics-based analysis of Lactobacillus acetotolerans G10, a strain using multiple carbon sources

Abstract:

[Background] Lactobacillus acetotolerans is the dominant lactic acid bacteria species and plays an important role in Chinese liquor fermentation. L. acetotoleran G10, which was isolated from the fermented grains of sesame-flavor liquor, utilizes multiple carbon sources. [Objective] To analyze the mechanism for the multiple carbon source utilization of G10 based on whole genome sequencing. [Methods] The whole genome of G10 was sequenced by Oxford Nanopore Technologies, a third-generation platform for the sequencing of native DNA strands. Circlator was employed to circularize genome assemblies and Prodigal to predict genes and annotate protein-coding genes. bacterial pan genome analysis tool (BPGA) was used for pan-genome analysis. [Results] G10 was able to utilize 22 sugars and their derivatives. The genome size of G10 was 1 627 828 bp with 1 878 coding genes. G10 contained 292 genes related to carbohydrate metabolism, as annotated by Koyto Encyclopedia of Genes and Genomes (KEGG) annotation, and 44 genes related to Carbohydrate-Active EnZymes (CAZy) according to the CAZy annotation. Compared with other L. acetotolerans from food fermentations, G10 had the smallest genome with the highest numbers of total genes and genes related to starch and sucrose metabolism, and contained 426 unique genes. Compared with Lactiplantibacillus plantarum subsp. plantarum ATCC 14917^T, Limosilactobacillus fermentum ATCC 14931^T, Lacticaseibacillus casei ATCC 393^T, Levilactobacillus brevis ATCC 14869^T and Lentilactobacillus buchneri ATCC 4005^T from food fermentations. The genome of G10 was the smallest. The number of genes related to carbohydrate metabolism accounted for the highest proportion of total genes in G10. It had unique genes such as glvA, malP and glvC. [Conclusion] G10 can use a variety of carbon sources and adapt to various fermentation environments. The analysis of genomic information lays a genetic basis for further illustration of the fermentation performance of L. acetotolerans.