A multi-aspect analysis of two analogous aspergillus spp. belonging to section Flavi: aspergillus flavus and aspergillus oryzae

Cross-linking of fungal β-glucosidase on Al2O3 nanocrystals synthesized using Cajanus cajan L. Millsp. extracts for in suit genistein manufacture

This present study deals with the cross-linking of fungal β-glucosidase on Al2O3 nanocrystals (NCs) synthesized in C. cajan for in-suit genistein production. The Cajanus cajan leaves were dried and used to prepare their extract at 65 °C by agitation for 30 min. For enzyme production under submerged culture, 50 mL of medium at pH 8.6 with an inoculum volume of 2 mL; was incubated for 72 h with optimized parameters at 30 °C. The Al2O3 NCs were synthesized by adding 30 mM Al2NO3 to 25 mL of leaf extract with NaOH at 65 °C for 50 min which enhanced the β-glucosidase specific activity when immobilized. Genistein by biotransformation was obtained using both free (0.67 ± 0.42 mg/mL) and Al2O3 immobilized β-glucosidase (1.3 ± 0.66 mg/mL) for 48 h. The substrate level and enzyme concentration were 2.5 and 1 mL respectively. The UV visible spectra for leaf extract; free and cross-linked β-glucosidase and Al2O3 NCs were at 225, 235, 300, and 210 nm. The bands for Al2O3 NCs were achieved at 500-750 cm- 1 which showed the FTIR analysis to check the change in functional groups of free and Al2O3 cross-linked β-glucosidase. In XRD analysis, peaks depicted the crystalline structure of Al2O3 NCs ranging from 10-50°. The size of NCs was confirmed by using different magnifications (1.01, 2.00, 3.00, 5.00, 7.02, and 10 K X) of SEM images obtained. For zeta potential measurements, the peak was obtained at -21.0 mV.

Locust Pathogen Aspergillus oryzae XJ1 Is Different from Aspergillus oryzae and Aspergillus flavus Based on Genomics Comparisons

Fungi play an increasingly important role in the biological control of insect pests. Aspergillus oryzae XJ1 is highly virulent to locust adults and nymphs, which are a destructive economic pest worldwide. Because of its host association with locusts, which is unique in Aspergillus, in this study, we examined the genetic relationships of A. oryzae XJ1 within Aspergillus. We sequenced the genome of A. oryzae XJ1 and compared it with the genomes of other Aspergillus species. The complete genome of A. oryzae XJ1 is 37.9 Mb, comprising 11,720 putative genes, assembled into eight chromosomes. The genome size is similar to that of other A. oryzae strains. Phylogenomic analysis indicated that A. oryzae XJ1 was most closely related to A. flavus NRRL3357, not A. oryzae RIB40. Core/pan-genome analysis of A. oryzae XJ1 and other Aspergillus species revealed that A. oryzae XJ1 had 704 strain-specific genes, whereas A. flavus NRRL3357, A. oryzae KDG 21, and A. parasiticus NRRL 2999 had 646, 955, and 779 unique genes, respectively. The A. oryzae XJ1 genome showed structural differences compared with the genomes of A. oryzae RIB40 and A. flavus NRRL3357 in genomic synteny analysis. These results indicate that A. oryzae XJ1 is genetically distinct at the genome level from other Aspergillus species, including A. oryzae and A. flavus, and may be as a distinct species. This will provide new insight into the classification of Aspergillus based on genomics.

The postbiotic potential of Aspergillus oryzae - a narrative review

The filamentous fungus Aspergillus oryzae has a long tradition in East Asian food processing. It is therefore not surprising that in recent years fermentation products of A. oryzae have attracted attention in the emerging field of postbiotics. This review aims to provide a comprehensive summary of the potential postbiotic effects of fermentation products from A. oryzae, by discussing possible mechanisms of action against the background of the molecular composition determined so far. In particular, cell wall constituents, enzymes, extracellular polymeric substances, and various metabolites found in A. oryzae fermentation preparations are described in detail. With reference to the generally assumed key targets of postbiotics, their putative beneficial bioactivities in modulating the microbiota, improving epithelial barrier function, influencing immune responses, metabolic reactions and signaling through the nervous system are assessed. Drawing on existing literature and case studies, we highlight A. oryzae as a promising source of postbiotics, particularly in the context of animal health and nutrition. Challenges and opportunities in quality control are also addressed, with a focus on the necessity for standardized methods to fully harness the potential of fungal-based postbiotics. Overall, this article sheds light on the emerging field of A. oryzae-derived postbiotics and emphasizes the need for further research to fully realize their therapeutic potential.

Comparative pangenome analysis of Aspergillus flavus and Aspergillus oryzae reveals their phylogenetic, genomic, and metabolic homogeneity

Aspergillus flavus and Aspergillus oryzae are closely related fungal species with contrasting roles in food safety and fermentation. To comprehensively investigate their phylogenetic, genomic, and metabolic characteristics, we conducted an extensive comparative pangenome analysis using complete, dereplicated genome sets for both species. Phylogenetic analyses, employing both the entirety of the identified single-copy orthologous genes and six housekeeping genes commonly used for fungal classification, did not reveal clear differentiation between A. flavus and A. oryzae genomes. Upon analyzing the aflatoxin biosynthesis gene clusters within the genomes, we observed that non-aflatoxin-producing strains were dispersed throughout the phylogenetic tree, encompassing both A. flavus and A. oryzae strains. This suggests that aflatoxin production is not a distinguishing trait between the two species. Furthermore, A. oryzae and A. flavus strains displayed remarkably similar genomic attributes, including genome sizes, gene contents, and G + C contents, as well as metabolic features and pathways. The profiles of CAZyme genes and secondary metabolite biosynthesis gene clusters within the genomes of both species further highlight their similarity. Collectively, these findings challenge the conventional differentiation of A. flavus and A. oryzae as distinct species and highlight their phylogenetic, genomic, and metabolic homogeneity, potentially indicating that they may indeed belong to the same species.