Abstract:Biomanufacturing is the primary method for amino acid production. However, conventional fermentation is limited to grain feedstocks, facing long-standing bottlenecks such as competition with the food supply and high costs. Therefore, developing novel green conversion systems based on non-grain feedstocks, such as agricultural waste and industrial by-products, is of great significance. This approach not only mitigates the industry’s reliance on limited grain resources but also facilitates the achievement of dual carbon goals. The research progress in amino acid synthesis from non-grain feedstocks, including cane molasses, lignocellulose, glycerol, and acetate, was summarized. Furthermore, the critical issues in bioconversion were identified, and the engineering strategies to overcome these obstacles were discussed to facilitate the construction of next-generation amino acid cell factories.

Abstract:Bacterial infectious diseases have long posed a serious challenge to global public health. Although conventional pathogen detection methods have made some achievements in clinical application, they still face the limitations of low sensitivity, long time consumption and so on. As new gene editing tools, CRISPR/Cas systems are widely used in pathogen detection because of the high efficiency and accuracy. The author summarized the technical principle, advantages, and disadvantages of CRISPR/Cas systems, and briefly reviewed the research progress of using CRISPR/Cas technology to detect different bacterial genera in recent years, aiming to provide reference for the detection of bacterial pathogens in the future.

Abstract:Candida antarctica (C. antarctica) is a yeast species found in the Antarctic environment. It produces two lipases, C. antarctica lipase A (CALA) and C. antarctica lipase B (CALB). In recent years, C. antarctica lipases have been widely used in the biological, chemical, and food industries for their strong catalytic efficiency and unique positional selectivity. This review first introduces the structural and enzymatic characteristics of C. antarctica lipases and then describes the application status of C. antarctica lipases in the preparation of diacylglycerol (DAG). Finally, the biological modification and immobilization status of the lipases are concluded and prospected. This review aims to provide theoretical and technical reference for the research on C. antarctica lipases in the fields such as DAG hydrolysis and esterification preparation and lay a foundation for the subsequent transformation and improvement of enzyme molecules.

Abstract:Neonicotinoid pesticides (NEOs) are widely used in global agricultural production because of their high efficiency, broad spectra, low toxicity, and low residues. However, improper use of NEOs will cause environmental pollution and pose a serious threat to human health. Therefore, developing new rapid detection technologies with field applicability and high throughput has become the focus of current research. The author reviewed the principles, advantages, and limitations of rapid detection technologies of neonicotinoid pesticide residues, and introduced in detail enzyme-linked immunosorbent assay, fluorescence immunoassay, immunochromatography, surface plasma resonance (SPR), surface-enhanced Raman scattering (SERS), fluorescence resonance energy transfer (FRET), molecular imprinting (MIT), and electrochemical sensors based on metal-organic frameworks (MOTs) and nanomaterials in the detection of neonicotinoid pesticide residues in agricultural products. With high sensitivity and high selectivity, the pesticide residue detection technologies represented by immunoassay, optical analysis, and electrochemical detection demonstrate great potential for the rapid detection of trace neonicotinoid pesticide residues, while they still have certain limitations in terms of detection limits, sensitivity, matrix treatment, etc. In the future practical testing, attention should be paid to the innovation and optimization in matrix effect elimination, intelligence and automation, and multi-functional integration.

Abstract:The biological activities of natural polysaccharides are often limited by their structures, which make it difficult to meet practical application requirements. Phosphorylation is an important chemical modification method, and the unique chemical structures can significantly enhance the antioxidant, immunomodulatory, and antitumor activities of phosphorylated polysaccharides. In recent years, this field has attracted widespread attention. To verify the success of phosphorylation and determine the degree and location of phosphorylation, various methods can be used to characterize the structures of phosphorylated polysaccharides. The author summarizes the latest research findings on phosphorylated polysaccharides and particularly focuses on their production methods, structural characterization, and biological activities, aiming to provide a theoretical foundation and practical recommendations for their application in food, pharmaceuticals, and related fields.

Abstract:Food safety is a major global issue concerning the national economy and people’s livelihood. Rapid, sensitive, and accurate detection of harmful substances in food is the key to ensuring food safety. As an emerging analytical technique, photoelectrochemical sensors combine photoelectric technology with biological sensing technology and have developed into a new type of photoelectric analysis sensors. They integrate the sensitivity of photochemistry and the simplicity of electrochemistry and have shown widespread applications in food safety detection due to their outstanding advantages such as high sensitivity, simple equipment, easy of miniaturization, and low costs. The author reviews the application examples and discusses the challenges of photoelectrochemical sensors in food safety detection, and makes an outlook on the future research directions.

Abstract:[Objective] This study aims to optimize the extraction process of polysaccharides from Opuntia ficus-indica (L.) Mill., improve the polysaccharide yield while reducing anthraquinone residue, and characterize the structure and evaluate the antioxidant activity of the obtained polysaccharides. [Method] The hot water extraction parameters were optimized by single factor and orthogonal tests. The anthraquinone residue was reduced by repeated washing with ethanol. The polysaccharide structure and composition were characterized by ultraviolet (UV) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and high performance gel permeation chromatography (HPGPC). The DPPH radical scavenging rate and oxygen radical absorbance capacity (ORAC) were measured to evaluate the in vitro antioxidant capacity. A HepaRG cell model of H₂O₂-induced oxidative stress was established, and the cell viability, intracellular reactive oxygen species (ROS) level, and the levels of glutathione peroxidase (GSH-Px), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) were determined. [Result] The optimal extraction conditions were extraction with a solid-to-liquid ratio of 1 g∶30 mL at 70 ℃ for 2.5 h. Structural characterization revealed three main weight-average molecular weights: 722.3×10³, 50.6×10³, and 1.6×10³. The polysaccharides consisted of 9 monosaccharides: mannose, glucuronic acid, rhamnose, galacturonic acid, glucose, galactose, xylose, arabinose, and fucose. The polysaccharides exerted the DPPH scavenging rate of 96.27% and the ORAC value of 0.66 mmol/L. The cell experiment showed that the polysaccharides (2.50 mg/mL and 5.00 mg/mL) significantly enhanced the activities of CAT, SOD and GSH-Px, while lowering the levels of MDA and ROS in the model HepaRG cells. [Conclusion]The optimized extraction process significantly improves the polysaccharide yield, and the obtained polysaccharides are high-purity heteropolysaccharides. Both in vitro and cell experiments demonstrate that the polysaccharides exhibit significant antioxidant activity, and its mechanism of action is associated with the regulation of oxidative stress-related biomarkers, highlighting its potential as a natural antioxidant for functional food applications.

Abstract:[Objective] This study aims to investigate the effects of negative ion treatment time on the preservation quality of fresh-cut apples. [Method] Fresh-cut apples were treated with negative ion for 0, 40, and 80 min. Under 4 ℃ preservation conditions, the respiration rate, browning index, mass fractions of soluble solids and titratable acids, activities of related enzymes, molality of malondialdehyde (MDA), mass fraction of total phenols, antioxidant capacity, and microbial growth of fresh-cut apples were measured. The effects of negative ion treatment on the preservation quality of fresh-cut apples were evaluated. [Result] Negative ion treatment effectively inhibited the microbial growth and respiration rate, reduced the nutrient loss and activities of polyphenol oxidase (PPO) and peroxidase (POD) activities, increased the molality of MDA, mass fraction of total phenols, and antioxidant capacity, and delayed surface browning, thereby improving the overall preservation quality of fresh-cut apples under 4 ℃ preservation conditions. Notably, the fresh-cut apples treated with negative ions for 80 min exhibited the best preservation quality. [Conclusion] Negative ion treatment improves the preservation quality of fresh-cut apples, demonstrating a promising application prospect.

Abstract:[Objective] This study constructed a succinic acid-producing cell factory for the efficient biosynthesis of succinic acid. [Method] Using Kluyveromyces marxianus (K. marxianus) as the chassis strain, an engineered yeast strain for the biosynthesis of succinic acid through comprehensive metabolic engineering strategies was constructed. These strategies encompassed the disruption of by-product synthesis pathways, enhancement of glycolytic flux, introduction of a heterologous succinic acid biosynthetic pathway, optimization of key enzyme expression, and augmentation of transmembrane transport of succinic acid. Finally, a fermentation process optimization was performed to improve the production performance. [Result] The engineered strain K. marxianus SA011 achieved a succinic acid titer of 10.06 g/L, a yield of 11.4%, and a productivity of 0.14 g/(L·h) in a 5 L bioreactor. [Conclusion] This study provides new insights into the metabolic engineering of K. marxianus and establishes a foundation for the efficient biosynthesis of succinic acid by yeast, facilitating its industrial application.

Abstract:[Objective]This study aims to investigate the digestion characteristics of yeast β-glucan and its effects on gut microbiota. [Method] On the basis of simulated digestion and the gut microbiota fermentation model of mice, 16S rRNA amplification sequencing and non-targeted metabolomics analysis were conducted to investigate the effects of yeast β-glucan on the microorganisms and metabolites of in vitro fermentation of mouse gut microbiota. [Result] Yeast β-glucan increased the microbial concentration in the in vitro fermentation broth, promoted the production of short-chain fatty acids, and significantly increased the proliferation of Firmicutes such as Lactobacillus murinus. Non-targeted metabolomics analysis showed that yeast β-glucan exerted its effects mainly through metabolism-related pathways, including glycerophospholipid, pathogenic Escherichia coli infection and linoleic acid metabolism. In addition, correlation analysis revealed highly significant correlations between characteristic bacteria and significantly changed metabolites. [Conclusion] Yeast β-glucan exerts functions such as modulating immunity by regulating the gut microbiota and promoting the production of fatty acid-related metabolites. The findings provide a theoretical basis for probing into the mechanism through which yeast β-glucan regulates the health of the body.

Abstract:[Objective] This study aims to explore the effect of microbial fermentation on the active substances in Platycodonis Radix from Shangcheng. [Method] With the mass fractions of total flavonoids and total polyphenols as evaluation indicators, the dominant microbial strains were screened. The selected strain was subsequently applied to the fermentation of Platycodonis Radix from Shangcheng. Single-factor experiments and orthogonal experiments were conducted to optimize the critical fermentation parameters including time, temperature, solid-to-liquid ratio, and inoculum mass fraction. The effect of microbial fermentation on the antioxidant activity in vitro of Platycodonis Radix from Shangcheng was evaluated with DPPH free radical scavenging rate, ABTS⁺ free radical scavenging rate, and total reducing power as indicators. [Result] Aspergillus niger (A. niger) H was identified as the dominant strain for fermentation. The fermentation conditions were optimized as follows: fermentation with a solid-to-liquid ratio of 1 g∶5.5 mL and an inoculum mass fraction of 11% at 33 ℃ for 4 d. Under these conditions, the mass fraction of total flavonoids reached (5.32±0.13) mg/g (representing a 1.19-fold increase compared with that before fermentation) and that of total polyphenols achieved (156.88±0.88) mg/g (representing a 1.20-fold enhancement compared with that before fermentation). Platycodonis Radix from Shangcheng before and after fermentation showed the IC₅₀ values of 0.030 mg/mL and 0.025 mg/mL for scavenging DPPH free radicals and 0.033 mg/mL and 0.021 mg/mL for scavenging ABTS⁺ free radicals, respectively. Total reducing power of Platycodonis Radix from Shangcheng was also substantially enhanced after fermentation. [Conclusion] The fermentation of Platycodonis Radix from Shangcheng with A. niger H could effectively improve the mass fractions of active ingredients and antioxidant capacity, which provided a theoretical basis for further research and development of Platycodonis Radix from Shangcheng.

Abstract:[Objective] This study aims to analyze the nutritional components of Holothuria leucospilota body wall, optimize the preparation process of Holothuria leucospilota oligopeptides, and evaluate their antioxidant activity in vitro. [Method] The basic nutritional components and amino acid composition were determined via national standard methods. Through protease screening and single-factor experiments combined with orthogonal design, the conditions for enzymatic hydrolysis were optimized, with the polypeptide yield and relative molecular weight distribution serving as evaluation indicators. Antioxidant activity in vitro of the obtained oligopeptides was assessed based on the free radical scavenging rates and Fe²⁺-chelating ability. [Result] The body wall of Holothuria leucospilota (on a dry basis) exhibited the highest crude protein mass fraction of (64.59±9.45)%. The conditions for enzymatic hydrolysis were optimized as follows: hydrolysis with 3 000 U/g alkaline protease and a solid-to-liquid ratio of 1 g∶11 mL at 70 ℃ and pH 9.5 for 3 h. Under these conditions, the polypeptide yield reached 75.75%, with over 98.00% of components having the relative molecular mass below 2 000. The IC₅₀ of the obtained oligopeptides for scavenging ABTS⁺ free radicals, scavenging hydroxyl free radicals, scavenging superoxide anion free radicals, and chelating Fe²⁺ were 0.93, 0.51, 8.97, and 0.40 mg/mL, respectively. [Conclusion] The body wall of Holothuria leucospilota is rich in high-quality protein. The established enzymatic hydrolysis process is efficient and feasible, with a high polypeptide yield. The obtained oligopeptides of Holothuria leucospilota demonstrate strong antioxidant activity, serving as a potential raw material for the development of functional foods.

Abstract:[Objective] This study aims to optimize the extraction process of polysaccharides from coffee peels and explore their structure and bioavailability. [Method] The composite enzymatic hydrolysis method was employed to extract polysaccharides from coffee peels. The polysaccharide structure was characterized from aspects such as infrared analysis, monosaccharide composition, molecular weight determination, and glycosidic linkage analysis. The bioavailability of the extracted polysaccharides was analyzed. [Result] The extraction process conditions were optimized as follows: a cellulase mass fraction of 2.6%, an alkaline protease mass fraction of 2.6%, a papain mass fraction of 2.6%, a pectinase mass fraction of 3.8%, an extraction temperature of 60 ℃, extraction time of 1.5 h, a solid-to-liquid ratio of 1 g∶100 mL, and pH 4. The composite enzymatic hydrolysis method effectively maintained the bioavailability of the polysaccharides. Structural characterization revealed that the coffee peel polysaccharides had a weight-average molecular weight of 1 626 765 and were composed of rhamnose, arabinose, galactose, glucose and galacturonic acid at a molar ratio of 4.39∶23.75∶28.03∶7.58∶36.25. It adopted an α-pyranose backbone and contained typical glycosidic linkages including →3)-Galp-(1→ and →4)-Galp-(1→. Galacturonic acid, as the major constituent, existed in the form of →4)-Galp-UA-(1→, which constituted the characteristic structural motif of the acidic polysaccharide. [Conclusion] This study provides a scientific reference for the in-depth research and development of coffee peels, a coffee by-product.

Abstract:[Objective] This study aims to reveal the biotransformation patterns and metabolic pathways of polyphenols in blueberry juice during mixed fermentation with Leuconostoc mesenteroides R2, Lactobacillus plantarum 9sh, and Lactobacillus fermentum SR2-6. [Method] Blueberry juice underwent mixed fermentation with Leuconostoc mesenteroides R2, Lactobacillus plantarum 9sh, and Lactobacillus fermentum SR2-6 selected in a previous study. Non-targeted metabonomics was conducted based on ultra-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS), and the maps of polyphenols and their differential metabolites were drawn. The polyphenols that changed significantly before and after fermentation were analyzed, and the metabolic pathways of polyphenol bioconversion were analyzed via Kyoto Encyclopedia of Genes and Genomes (KEGG). [Result] The fermented blueberry juice contained 726 polyphenols, which included 44.77% flavonoids, 41.32% phenolic acids, 11.98% lignins and coumarins, 0.83% tannins, and 1.10% others. In addition, there were many bioconversion pathways of polyphenols during fermentation, among which tyrosine metabolism, phenylalanine metabolism and other metabolic pathways were significantly enriched. [Conclusion] Mixed fermentation of blueberry juice with Leuconostoc mesenteroides R2, Lactobacillus plantarum 9sh, and Lactobacillus fermentum SR2-6 can produce a variety of polyphenols including flavonoids and phenolic acids. The metabolic pathways mainly involve tyrosine metabolism, phenylalanine metabolism and others. This study can provide a reference for the bioconversion of polyphenols in blueberry juice fermented by lactic acid bacteria.

Abstract:[Objective] This study aims to investigate the regulatory effects of bovine colostrum bioactive components and their combination with collagen peptides on collagen synthesis and metabolism. [Method] Cell experiments were conducted to evaluate the effects of bovine colostrum bioactive components on type I collagen (COL I) secretion, lysyl hydroxylase 1 (LH1), matrix metalloproteinase 1 (MMP-1), and matrix metalloproteinase 3 (MMP-3) activities, as well as human transforming growth factor β1 (TGFB1) gene expression in human skin fibroblasts (HSF). Subsequently, a mouse model of collagen loss induced by D-galactose was established to investigate the regulatory effects of oral administration of bovine colostrum bioactive components and their combination with collagen peptides on the mass fractions of type I, III, IV, and VII collagen, mass fraction of mouse transforming growth factor β1(TGF-β1), and activities of MMP-3, prolyl 4-hydroxylase (P4H), lysyl oxidase (LOX), and LH1 in the mouse skin. [Result] At the cellular level, bovine colostrum bioactive components promoted COL I secretion in HSFs, significantly increased LH1 activity, inhibited MMP-1 and MMP-3 activities, and upregulated TGFB1 gene expression. In the mouse model of D-galactose-induced collagen loss, oral administration of bovine colostrum bioactive components increased the mass fractions of type I, III, IV, and VII collagen, enhanced the LOX activity and elevated TGF-β1 level, and inhibited the MMP-3 activity in the mouse skin. Moreover, the combination of bovine colostrum bioactive components with collagen peptides significantly enhanced the activities of P4H, LOX, and LH1, as well as the TGF-β1 level, resulting in a more pronounced increase in collagen mass fraction in the skin. [Conclusion] Bovine colostrum bioactive components can enhance the collagen mass fraction both in vitro and in vivo by regulating collagen synthesis and metabolism. Their combination with collagen peptides exhibits a synergistic effect. These findings provide a theoretical basis for the application of bovine colostrum bioactive components in improving collagen metabolism and offer a reference for the development of food-derived collagen supplements.

Abstract:[Objective] This study aims to screen high-quality food-borne lactic acid bacteria. [Method] Lactic acid bacteria were isolated, purified, and identified from traditional fermented sweet oats (Tianpeizi) in Lanzhou by conventional microbial culture methods combined with 16S rRNA gene sequencing. The probiotic properties of the isolates were comprehensively evaluated based on acid and bile salt tolerance, antibiotic susceptibility, antibacterial activity, and in vitro antioxidant capacity. [Result] A total of six strains of lactic acid bacteria were isolated and identified from Tianpeizi in Lanzhou, including Lacticaseibacillus paracasei (L. paracasei) PR6, Limosilactobacillus fermentum (L. fermentum) PR10, Weissella paramesenteroides (W. paramesenteroides) PR13, Pediococcus pentosaceus (P. pentosaceus) PR15, Pediococcus acidilactici (P. acidilactici) PR17, and Weissella confusa (W. confusa) PR18. The probiotic property assay showed that strain PR10 exhibited high survival rates under acidic conditions (pH 2.5 and 3.0) and in the presence of bile salts. It showed moderate to high susceptibility to commonly used antibiotics, including ciprofloxacin, ampicillin, tetracycline, and penicillin, and demonstrated strong inhibitory activity against foodborne pathogens (Staphylococcus aureus and Escherichia coli). Strain PR18 displayed notable antioxidant activity, with 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging rate and reducing power of 67.6% and 42.7%, respectively. In addition, strain PR18 showed good acid and bile salt tolerance, second only to strain PR10. [Conclusion] L. fermentum PR10 and W. confusa PR18 exhibit promising probiotic potential and may serve as candidate strains for further studies.