Strain JR3^T was isolated from Chinese pickled potherb mustard (Brassica juncea Coss.) purchased from a local market in Shanghai, China. A polyphasic approach including 16S rRNA gene sequence analysis, average nucleotide identity (ANI) analysis, digital DNA–DNA hybridization (dDDH), determination of G+C content and various phenotypic analyses was employed to characterize strain JR3^T. The bacterium was rod-shaped, Gram-stain-positive, terminal round endospore-forming and catalase-positive. The strain could grow at a wide range of temperatures (20–45 °C) and pH values (6.0–8.0). Optimal growth of strain JR3^T occurred at 35–40 °C and a pH value of 7.0. The strain exhibited growth at salt (NaCl) concentrations of up to 3% (w/v). The G+C content of the genomic DNA was 44.0 mol%. The major fatty acids were C16 : 0, C19 : 0 c9, 10, summed feature 10 (C18 : 1 c11/t9/t6) and C18 : 1 c9. 16S rRNA gene sequencing revealed that strain JR3^T represents a member of the genus Lacrimispora, and it has higher sequence similarity with Lacrimispora amygdalina BR-10^T (=DSM 12857^T) (98.72%), Lacrimispora saccharolyticum WM1^T (98.29%) and Lacrimispora xylanolytica sy1 (98.22%). The dDDH value for strain JR3^T and phylogenetically related species within the genus Lacrimispora ranged from 17.7% to 29.9%. The ANI of strain JR3^T with its closely related taxa was far lower than the threshold (95%−96%) used for species differentiation. Results of phylogenetic, physiological and phenotypic characterization confirmed that strain JR3^T represented a novel species within the genus Lacrimispora, for which the name Lacrimispora sinapis sp. nov. is proposed. The type strain is JR3^T=CCTCC AB 2024044^T=LMG 33655^T.

Monascus species are widely used in traditional fermented foods for pigment and flavor formation, but citrinin contamination remains a major safety concern that limits broader food applications. Therefore, this study aimed to evaluate the citrinin risk of a furu-derived Monascus ruber strain, BC20, by integrating phenotypic screening across food-relevant matrices with genome-resolved analysis. After 14 days of cultivation across eight matrices, including fungal media as well as dairy-, cereal-, and bran-based substrates, citrinin was not detected by immunoaffinity cleanup combined with HPLC–FLD (LOD, 4 μg/kg; LOQ, 12 μg/kg). To investigate the genetic basis of this phenotype, we generated a chromosome-scale genome assembly for BC20 and conducted comparative analyses across a total of 19 Monascus genomes. ANI analysis and phylogenomic inference consistently placed BC20 within the ruber–pilosus clade. Comparative synteny analysis showed that the citrinin-associated locus in BC20 no longer retained an intact cluster configuration but instead exhibited a remnant-locus architecture, and similar patterns were also observed in several related genomes from the same clade. By contrast, the monacolin K (mk) locus remained syntenically conserved in BC20, supporting locus-specific structural disturbance rather than assembly-derived pseudo-absence. Additionally, its antifungal susceptibility was determined. Overall, BC20 represents a M. ruber candidate strain with undetectable citrinin, and this study provides a practical analytical framework for citrinin risk screening in food-related Monascus isolates.