Abstract
The sourdough isolates FUA3702, FUA3912 and FUA3913(T), as well as FUA3695(T) and FUA3914, could not be identified to known species of the Lactobacillaceae. The 16S rRNA gene sequences of FUA3702 and FUA3913, FUA3695 and FUA3914 were>99% identical to Fructilactobacillus sanfranciscensis and Levilactobacillus lanxiensis, respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values of strain FUA3913(T) when compared to Fl. sanfranciscensis were 83.67 and 26.60%, respectively. In addition, strains FUA3702, FUA3912 and FUA3913(T) produce different levels of a yellow C30 carotenoid, but pigmentation has not been described in Fl. sanfranciscensis. The ANI and dDDH values of FUA3695(T) and FUA3914 when compared to Lv. langxiensis were 95.22 and 61.20%, respectively. In addition, FUA3695 and FUA3914 convert lactate to 1,2-propanediol and further to propionate. The conversion of lactate to propionate by a single strain has not been documented for any of the species in the Lactobacillaceae. Based on the genomic and physiological characteristics, we proposed the novel species Fructilactobacillus frigidiflavus sp. nov. FUA3913(T) (=DSM 118650(T)=LMG 33758(T)) and Levilactobacillus lettrarii sp. nov. FUA3695(T) (=DSM 118651(T)=LMG 33759(T)).