Reducing biogenic amine in seriflux and huangjiu by recycling of seriflux inoculated with Lactobacillus plantarum JN01

Research progress on the diversity, physiological and functional characteristics of lactic acid bacteria in the Nongxiangxing baijiu microbiome

Nongxiangxing baijiu (NXXB) is one of the main types of Chinese Baijiu. Its unique flavor is formed during fermentation by the combined action of various microorganisms, with lactic acid bacteria (LAB) making a great contribution. Lactate fermentation produces the precursors of key flavor compounds, such as lactic acid, acetic acid, and other flavor compounds, which combine to produce the unique sensory characteristics of NXXB. This review focuses on the diversity of LAB species and their physiological and metabolic characteristics. These characteristics include key species involved at different fermentation stages, metabolite biosynthesis, acid-tolerance mechanisms, interactions with yeasts, and factors influencing LAB community composition. It also discusses current challenges and future research directions for LAB in relation to NXXB production, aiming to advance understanding and potential future applications of these bacteria.

The Microbial Diversity and Flavor Metabolism Regulation of Xiangzao During Different Natural Fermentation Time Periods

Xiangzao brine is a special flavored food produced by the natural fermentation of Huangjiu lees. To clarify fermentation time on its quality, this study integrated flavoromics analysis, macro-genomics, and polypeptide omics to analyze the volatile flavor components, microbial species, and flavor peptide distributions of four groups of samples (XZ-1Y, XZ-2Y, XZ-3Y, and XZ-4Y) fermented for 1-4 years. The results showed that the samples fermented for 1 year had the highest contents of umami amino acids and umami peptides, and the samples fermented for 4 years had the highest contents of organic acids and fruity components. In addition, 42 volatile flavor components and 532 peptides were identified, including 393 umami taste peptides and only 37 bitter taste peptides. Correlation analysis showed that ethyl lactate and furfural were positively correlated with the abundance of Nocardioides and Stenotrophomonas, respectively. The abundance of Pseudomonas was positively correlated with four previously unreported umami peptides (FATPR, RELER, FNLERP, and RSSFLGQ) screened by molecular docking. This study provides a reference for the flavor metabolism regulation of Xiangzao brine.

Identification of Enzymes and Their Key Action Sites for Histamine Degradation in Mulberry Fruit Wine by Lactiplantibacillus plantarum

In this study, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and multicopper oxidase (MCO) of Lactiplantibacillus plantarum W155 with histamine degradation ability were expressed. The mulberry fruit wine (MFW) histamine degradation abilities of GAPDH and MCO were 20.81% and 37.67%, respectively. Compared with the control group, the MFW treated by GAPDH showed higher total phenolic (1.17 g GAE/L) and total flavonoid (0.31 g RE/L) contents, while MFW treated by MCO presented similar total phenolic (1.00 g GAE/L) and total flavonoid (0.29 g RE/L) concentrations. Furthermore, the optimal pH and temperature of GAPDH were 6.0 and 40 °C, respectively, while the optimal pH and temperature of MCO were 3.0 and 50 °C, respectively. Meanwhile, the key action sites for histamine degradation of GAPDH and MCO were minded via homology modeling, molecular docking, and site-directed mutagenesis. Val209 and Ile290 were confirmed as the key action sites for GAPDH, while Qln402 and Leu420 were the pivotal action sites for MCO. Above findings indicated that both GAPDH and MCO of L. plantarum W155 could be used to control the histamine of MFW, and the key action sites of these two enzymes could be used as targets for their subsequent modification.

Multicopper Oxidase from Lactobacillus hilgardii: Mechanism of Degradation of Tyramine and Phenylethylamine in Fermented Food

Elevated levels of biogenic amines (BAs) in fermented food can have negative effects on both the flavor and health. Mining enzymes that degrade BAs is an effective strategy for controlling their content. The study screened a strain of Lactobacillus hilgardii 1614 from fermented food system that can degrade BAs. The multiple copper oxidase genes LHMCO1614 were successfully mined after the whole genome protein sequences of homologous strains were clustered and followed by homology modeling. The enzyme molecules can interact with BAs to stabilize composite structures for catalytic degradation, as shown by molecular docking results. Ingeniously, the kinetic data showed that purified LHMCO1614 was less sensitive to the substrate inhibition of tyramine and phenylethylamine. The degradation rates of tyramine and phenylethylamine in huangjiu (18% vol) after adding LHMCO1614 were 41.35 and 40.21%, respectively. Furthermore, LHMCO1614 demonstrated universality in degrading tyramine and phenylethylamine present in other fermented foods as well. HS-SPME-GC-MS analysis revealed that, except for aldehydes, the addition of enzyme treatment did not significantly alter the levels of major flavor compounds in enzymatically treated fermented foods (p > 0.05). This study presents an enzymatic approach for regulating tyramine and phenylethylamine levels in fermented foods with potential applications both targeted and universal.

Mitigation of microbial nitrogen-derived metabolic hazards as a driver for safer alcoholic beverage choices: An evidence-based review and future perspectives

Alcoholic beverages have been enjoyed worldwide as hedonistic commodities for thousands of years. The unique quality and flavor are attributed to the rich microbiota and nutritional materials involved in fermentation. However, the metabolism of these microbiota can also introduce toxic compounds into foods. Nitrogen-derived metabolic hazards (NMH) are toxic metabolic hazards produced by microorganisms metabolizing nitrogen sources that can contaminate alcoholic beverages during fermentation and processing. NMH contamination poses a risk to dietary safety and human health without effective preventive strategies. Existing literature has primarily focused on investigating the causes of NMH formation, detection methods, and abatement techniques for NMH in fermentation end-products. Devising effective process regulation strategies represents a major challenge for the alcoholic beverage industry considering our current lack of understanding regarding the processes whereby NMH are generated, real-time and online detection, and the high degradation rate after NMH formation. This review summarizes the types and mechanisms of nitrogenous hazard contamination, the potential risk points, and the analytical techniques to detect NMH contamination. We discussed the changing patterns of NMH contamination and effective strategies to prevent contamination at different stages in the production of alcoholic beverages. Moreover, we also discussed the advanced technologies and methods to control NMH contamination in alcoholic beverages based on intelligent monitoring, synthetic ecology, and computational assistance. Overall, this review highlights the risks of NMH contamination during alcoholic beverage production and proposes promising strategies that could be adopted to eliminate the risk of NMH contamination.

Electrospun nanofibrous poly(ether-block-amide) membrane for removing biogenic amines in acidic wastewater from the yellow rice wine factory

Compared with other techniques for wastewater treatment, adsorption offers an effective, economical and ecofriendly way to reduce the content of biogenic amines. Herein, the poly(ether-block-amide) (PEBA 2533) membranes were employed as the adsorbent to remove histamine, putrescine, cadaverine and tyramine in the synthetic and real wastewater from a local yellow rice wine factory. Electrospun PEBA membranes consisting of fine nanofibers were successfully obtained without the addition of surfactant for the first time. Characteristics of the prepared membranes were evaluated by their morphology, wetting behaviors and mechanical properties. Adsorption performance of the nanofibrous membrane was investigated in comparison to the dense membrane prepared by conventional casting. The fibrous membrane exhibited much higher adsorption rate over 10 times to the dense membrane along with 1.5 times more adsorption capacity towards the amines. In addition, the as-prepared membrane showed a promising reusability in the real wastewater treatment. The good balance of its chemical stability, adsorption capacity, selectivity, removal efficiency and reusability endows the electrospun membrane with an outstanding potential to be applied in the acidic wastewater treatment for the yellow rice wine industry.

Complete genome sequence, metabolic model construction, and huangjiu application of Saccharopolyspora rosea A22, a thermophilic, high amylase and glucoamylase actinomycetes

Saccharopolyspora is an important microorganism in the fermentation process of wheat qu and huangjiu, yet the mechanisms by which it performs specific functions in huangjiu remain unclear. A strain with high amylase and glucoamylase activities was isolated from wheat qu and identified as Saccharopolyspora rosea (S. rosea) A22. We initially reported the whole genome sequence of S. rosea A22, which comprised a circular chromosome 6,562,638 bp in size with a GC content of 71.71%, and 6,118 protein-coding genes. A functional genomic analysis highlighted regulatory genes involved in adaptive mechanisms to harsh conditions, and in vitro experiments revealed that the growth of S. rosea A22 could be regulated in response to the stress condition. Based on whole-genome sequencing, the first genome-scale metabolic model of S. rosea A22 named iSR1310 was constructed to predict the growth ability on different media with 91% accuracy. Finally, S. rosea A22 was applied to huangjiu fermentation by inoculating raw wheat qu, and the results showed that the total higher alcohol content was reduced by 12.64% compared with the control group. This study has elucidated the tolerance mechanisms and enzyme-producing properties of S. rosea A22 at the genetic level, providing new insights into its application to huangjiu.

Effects of the microbial community on the formation of volatile compounds and biogenic amines during the traditional brewing of Hongqu rice wine

As a typical representative of Chinese rice wine (Huangjiu), Hongqu rice wine is famous for its red color, mellow taste and strong fragrance. However, due to the open brewing environment and traditional fermentation technology, there are some safety risks in traditional brewed Hongqu rice wine, such as a certain amount of biogenic amines. In this study, the dynamic changes and the differences of microbial communities and volatile flavor components between two types of Hongqu rice wine with high and low biogenic amine contents (LBAW and HBAW) during the traditional brewing were systematically investigated. The results showed that the total biogenic amine contents in LBAW and HBAW were 20.91 and 69.06 mg/L, respectively. The contents of putrescine, cadaverine, spermine and spermidine in HBAW were significantly higher than those in LBAW, and it was noteworthy that spermine content in HBAW was 17.62 mg/L, which was not detected in LBAW. In addition, the volatile flavor characteristics of the two kinds of Hongqu rice wine were obviously different. The contents of acetophenone, n-butyl butanoate and benzothiazole were obviously higher in HBAW, while the contents of isoamyl acetate, ethyl lactate, ethyl caprate and phenylethyl alcohol were significantly higher in LBAW. High-throughput sequencing of 16S/ITS amplicon revealed that Weissella, Kosakonia, Pantoea, Monascus, Saccharomyces and Millerozyma were the predominant microbial genera during the traditional brewing of HBAW, while Weissella, Kosakonia, Monascus, Saccharomyces and Issatchenkia were the predominant microbial genera during the traditional brewing of LBAW. Correlation analysis revealed that biogenic amines were significantly negatively correlated with unclassified_o_Saccharomycetales, Cyberlindnera, Zygoascus, Aspergillus and Acinetobacter, but positively correlated with Lactobacillus, Pediococcus, Millerozyma and Apiotrichum. In addition, we also found that Lactobacillus, Pediococcus and Saccharomyces were significantly positively correlated with most of the volatile flavor components, while Candida, Trichosporon and Monascus were significantly negatively correlated with most of the volatile flavor components. In addition, bioinformatical analysis based on PICRUSt demonstrated that the key enzymes for biogenic amine biosynthesis were more abundant in the microbial community of HBAW than LBAW. These findings demonstrate that the formations of volatile flavor and biogenic amines in Hongqu rice wine are influenced by microbial community during the fermentation. This work facilitates scientific understanding of the formation mechanism of biogenic amines, and may be useful to develop effective strategies to improve the quality of Hongqu rice wine.