Effect of cellulase on antioxidant activity and flavor of Rosa roxburghii Tratt.

Cellulase can increase the soluble dietary fiber (SDF) content in Rosa roxburghii Tratt (RRT), but the effects on polyphenol content, bioactivity, and flavor are unknown. This study analyzed the changes in SDF content, total phenolic content, antioxidant activity and flavor before and after cellulase treatment. Cellulase treatment increased the SDF and total phenolic content of RRT by 13 % (P < 0.05) and 25.68 % (P < 0.05), respectively, and increased the antioxidant activity. HS-GC-IMS identified a total of 42 volatile compounds present, and ROAV analysis revealed that the characteristic aroma compounds of RRT were mainly aldehydes, alcohols, and ethers. The electronic nose and tongue results were consistent with the HS-GC-IMS analysis, indicating the positive effect of cellulase on the quality of RRT. Cellulase treatment significantly improved the oxidative activity and flavor performance of RRT. These results of RRT, providing practical guidance for improving the flavor and product quality.

Contribution of trehalose to ethanol stress tolerance of Wickerhamomyces anomalus.

BACKGROUND: The ascomycetous heterothallic yeast Wickerhamomyces anomalus (WA) has received considerable attention and has been widely reported in the winemaking industry for its distinctive physiological traits and metabolic attributes. An increased concentration of ethanol during ethanol fermentation, however, causes ethanol stress (ES) on the yeast cells. Trehalose has been implicated in improving survival under various stress conditions in microorganisms. Herein, we determined the effects of trehalose supplementation on the survival, differentially expressed genes (DEGs), cellular morphology, and oxidative stress tolerance of WA in response to ES. RESULTS: The results indicated that trehalose improved the survival and anomalous surface and ultrastructural morphology of WA. Additionally, trehalose improved redox homeostasis by reducing the levels of reactive oxygen species (ROS) and inducing the activities of antioxidant enzymes. In addition, DEGs affected by the application of trehalose were enriched in these categories including in gene expression, protein synthesis, energy metabolism, and cell cycle pathways. Additionally, trehalose increased the content of intracellular malondialdehyde (MDA) and adenosine triphosphate. CONCLUSIONS: These results reveal the protective role of trehalose in ES mitigation and strengthen the possible uses of WA in the wine fermentation sector.

Protective effects of thiamine on Wickerhamomyces anomalus against ethanol stress.

Wickerhamomyces anomalus (W. anomalus) is widely reported in the brewing industry and has positive effects on the aromatic profiles of wines because of its unique physiological characteristics and metabolic features. However, the accumulation of ethanol during fermentation inhibits the growth of W. anomalus. Thiamine is involved in the response against various abiotic stresses in microorganisms. Therefore, we used transcriptomic and metabolomic analyses to study the effect of thiamine on ethanol-stressed W. anomalus. The results indicate that thiamine could alleviate the inhibitory effect of ethanol stress on the survival of W. anomalus. Differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) caused by the thiamine intervention were identified as oxidative phosphorylation through integrated transcriptomic and metabolomic analyses. In addition, ethanol treatment decreased the content of intracellular adenosine triphosphate (ATP), while thiamine partially alleviated this phenomenon. The present comprehensive transcriptional overview and metabolomic analysis provide insights about the mechanisms of thiamine protection on W. anomalus under ethanol stress and promote the potential applications of W. anomalus in the fermentation industry.

Analysis of the ethanol stress response mechanism in Wickerhamomyces anomalus based on transcriptomics and metabolomics approaches.

BACKGROUND: Wickerhamomyces anomalus (W. anomalus) is a kind of non-Saccharomyces yeast that has a variety of unique physiological characteristics and metabolic features and is widely used in many fields, such as food preservation, biomass energy, and aquaculture feed protein production. However, the mechanism of W. anomalus response to ethanol stress is still unclear, which greatly limits its application in the production of ethanol beverages and ethanol fuels. Therefore, we checked the effects of ethanol stress on the morphology, the growth, and differentially expressed genes (DEGs) and metabolites (DEMs) of W. anomalus. RESULTS: High concentrations of ethanol (9% ethanol and 12% ethanol) remarkably inhibited the growth of W. anomalus. Energy metabolism, amino acid metabolism, fatty acids metabolism, and nucleic acid metabolism were significantly influenced when exposing to 9% ethanol and 12% ethanolstress, which maybe universal for W. anomalus to response to different concentrations of ethanol stressl Furthermore, extracellular addition of aspartate, glutamate, and arginine significantly abated ethanol damage and improved the survival rate of W. anomalus. CONCLUSIONS: The results obtained in this study provide insights into the mechanisms involved in W. anomalus response to ethanol stress. Therefore, new strategies can be realized to improve the ethanol tolerance of W. anomalus through metabolic engineering.

[Study on electrochemical degradation of acid red B(ARB)].

The electrochemical degradation of acid red B (ARB) with hydrogen peroxide and hypochlorite ion electrogenerated by paired electrooxidation technology was investigated. High performance liquid chromatography (HPLC) was used to inspect the degradation process of ARB. Through analyzing chromatographic survey and UV-Vis spectra, as well as the removal of CODCr, TOC and color in the anode and cathode cells, the degradation processes of ARB in different cells were different. The color removal in the cathode cell was slower than in the anode cell, but the CODCr and TOC removal, which were 71.70% and 56.40% respectively, was higher than the removal in the anode cell, which were 25.15% and 27.57%. It maybe result from the different oxidation capabilities of the electrogenerated substances in the anode and cathode cells.