In recent years, minor ginsenosides have received increasing attention due to their outstanding biological activities, yet they are of extremely low content in wild ginseng. Ginsenoside Rb1, which accounts for 20% of the total ginsenosides, is commonly used as a precursor to produce minor ginsenosides via β-glucosidases. To date, many research groups have used different approaches to obtain β-glucosidases that can hydrolyze ginsenoside Rb1. This paper provides a compilation and analysis of relevant literature published mainly in the last decade, focusing on enzymatic hydrolysis pathways, enzymatic characteristics and molecular mechanisms of ginsenoside Rb1 hydrolysis by β-glucosidases. Based on this, it can be concluded that: (1) The β-glucosidases that convert ginsenoside Rb1 are mainly derived from bacteria and fungi and are classified as glycoside hydrolase (GH) families 1 and 3, which hydrolyze ginsenoside Rb1 mainly through the six pathways. (2) Almost all of these β-glucosidases are acidic and neutral enzymes with molecular masses ranging from 44–230 kDa. Furthermore, the different enzymes vary widely in terms of their optimal temperature, degradation products and kinetics. (3) In contrast to the GH1 β-glucosidases, the GH3 β-glucosidases that convert Rb1 show close sequence-function relationships. Mutations affecting the substrate binding site might alter the catalytic efficiency of enzymes and yield different prosapogenins. Further studies should focus on elucidating molecular mechanisms and improving overall performances of β-glucosidases for better application in food and pharmaceutical industries.

Phytase supplied in feeds for monogastric animals is important for improving nutrient uptake and reducing phosphorous pollution. High-thermostability phytases are particularly desirable due to their ability to withstand transient high temperatures during feed pelleting procedures. A comparison of crystal structures of the widely used industrial Aspergillus niger PhyA phytase (AnP) with its close homolog, the thermostable Aspergillus fumigatus phytase (AfP), suggests 18 residues in three segments associated with thermostability. In this work, we aim to improve the thermostability of AnP through site-directed mutagenesis. We identified favorable mutations based on structural comparison of homologous phytases and molecular dynamics simulations. A recombinant phytase (AnP-M1) was created by substituting 18 residues in AnP with their AfP analogs. AnP-M1 exhibited greater thermostability than AnP at 70 °C. Molecular dynamics simulations suggested newly formed hydrogen bonding interactions with nine substituted residues give rise to the improved themostability. Thus, another recombinant phytase (AnP-M2) with just these nine point substitutions was created. AnP-M2 demonstrated superior thermostability among all AnPs at ≥70 °C: AnP-M2 maintained 56% of the maximal activity after incubation at 80 °C for 1 h; AnP-M2 retained 30-percentage points greater residual activity than that of AnP and AnP-M1 after 1 h incubation at 90 °C. The resulting AnP-M2 is an attractive candidate in industrial applications, and the nine substitutions in AnP-M2 are advantageous for phytase thermostability. This work demonstrates that a strategy combining structural comparison of homologous enzymes and computational simulation to focus on important interactions is an effective method for obtaining a thermostable enzyme.

Enzymatic degradation of chitin has attracted substantial attention because chitin is an abundant renewable natural resource, second only to lignocellulose, and because of the promising applications of N-acetylglucosamine in the bioethanol, food and pharmaceutical industries. However, the low activity and poor tolerance to salts and N-acetylglucosamine of most reported β-N-acetylglucosaminidases limit their applications. Mining for novel enzymes from new microorganisms is one way to address this problem. A glycoside hydrolase family 20 (GH 20) β-N-acetylglucosaminidase (GlcNAcase) was identified from Microbacterium sp. HJ5 harboured in the saline soil of an abandoned salt mine and was expressed in Escherichia coli. The purified recombinant enzyme showed specific activities of 1773.1 ± 1.1 and 481.4 ± 2.3 μmol min−1 mg−1 towards p-nitrophenyl β-N-acetylglucosaminide and N,N'-diacetyl chitobiose, respectively, a V max of 3097 ± 124 μmol min−1 mg−1 towards p-nitrophenyl β-N-acetylglucosaminide and a K i of 14.59 mM for N-acetylglucosamine inhibition. Most metal ions and chemical reagents at final concentrations of 1.0 and 10.0 mM or 0.5 and 1.0% (v/v) had little or no effect (retaining 84.5 − 131.5% activity) on the enzyme activity. The enzyme can retain more than 53.6% activity and good stability in 3.0–20.0% (w/v) NaCl. Compared with most GlcNAcases, the activity of the enzyme is considerably higher and the tolerance to salts and N-acetylglucosamine is much better. Furthermore, the enzyme had higher proportions of aspartic acid, glutamic acid, alanine, glycine, random coils and negatively charged surfaces but lower proportions of cysteine, lysine, α-helices and positively charged surfaces than its homologs. These molecular characteristics were hypothesised as potential factors in the adaptation for salt tolerance and high activity of the GH 20 GlcNAcase. Biochemical characterization revealed that the GlcNAcase had novel salt–GlcNAc tolerance and high activity. These characteristics suggest that the enzyme has versatile potential in biotechnological applications, such as bioconversion of chitin waste and the processing of marine materials and saline foods. Molecular characterization provided an understanding of the molecular–function relationships for the salt tolerance and high activity of the GH 20 GlcNAcase.

Background/Objectives: Obesity is increasingly recognized as a global health concern due to its association with metabolic disorders and gut microbiota dysbiosis. While probiotics offer promise in regulating gut microbiota and improving host metabolism, strain-specific effects remain underexplored, particularly for canine-derived probiotics. This study aimed to isolate and characterize a novel probiotic strain, Ligilactobacillus animalis LA-1, and evaluate its anti-obesity effects and underlying mechanisms using a high-fat diet (HFD)-induced obese mouse model. Methods: LA-1 was isolated from the feces of a healthy dog and assessed for probiotic potential in vitro, including gastrointestinal tolerance, bile salt hydrolase activity, cholesterol-lowering capacity, and fatty acid absorption. Male C57BL/6J mice were fed either a standard chow diet or an HFD for 16 weeks, with HFD mice receiving oral LA-1 supplementation (2 × 10⁹ CFU/day). Multi-omics analyses, including 16S rRNA gene sequencing, short-chain fatty acid (SCFA) quantification, and untargeted liver metabolomics, were employed to investigate the effects of LA-1 on gut microbiota composition, metabolic pathways, and obesity-related phenotypes. Results: LA-1 supplementation significantly alleviated HFD-induced weight gain, hepatic lipid accumulation, and adipose tissue hypertrophy, without affecting food intake. It improved serum lipid profiles, reduced liver injury markers, and partially restored gut microbiota composition, decreasing the Firmicutes/Bacteroidetes ratio and enriching SCFA-producing genera. Total SCFA levels, particularly acetate, propionate, and butyrate, increased following LA-1 treatment. Liver metabolomics revealed that LA-1 modulated pathways involved in lipid and amino acid metabolism, resulting in decreased levels of acetyl-CoA, triglycerides, and bile acids. Conclusions: L. animalis LA-1 exerts anti-obesity effects via gut microbiota modulation, enhanced SCFA production, and hepatic metabolic reprogramming. These findings highlight its potential as a targeted probiotic intervention for obesity and metabolic disorders.

This research sought to assess the anti-obesity potential of Enterococcus faecalis EF-1. An extensive and robust in vitro methodology confirmed EF-1’s significant potential in combating obesity, probably due to its excellent gastrointestinal tract adaptability, cholesterol-lowering property, bile salt hydrolase activity, α-glucosidase inhibition, and fatty acid absorption ability. Moreover, EF-1 exhibited antimicrobial activity against several pathogenic strains, lacked hemolytic activity, and was sensitive to all antibiotics tested. To further investigate EF-1’s anti-obesity properties in vivo, a high-fat diet (HFD) was used to induce obesity in C57BL/6J mice. Treatment with EF-1 (2 × 10⁹ CFU/day) mitigated HFD-induced body weight gain, reduced adipose tissue weight, and preserved liver function. EF-1 also ameliorated obesity-associated microbiota imbalances, such as decreasing the Firmicutes/Bacteroidetes ratio and boosting the levels of bacteria (Faecalibacterium, Mucispirillum, Desulfovibrio, Bacteroides, and Lachnospiraceae_NK4A136_group), which are responsible for the generation of short-chain fatty acids (SCFAs). Concurrently, the levels of total SCFAs were elevated. Thus, following comprehensive safety and efficacy assessments in vitro and in vivo, our results demonstrate that E. faecalis EF-1 inhibits HFD-induced obesity through the regulation of gut microbiota and enhancing SCFA production. This strain appears to be a highly promising candidate for anti-obesity therapeutics or functional foods.