通讯机构：
[Zhou, B; Zhou, X; Zhong, HY ; Lu, D ] C;[Zhou, B ] H;Cent South Univ Forestry & Technol, Coll Food Sci & Engn, Changsha, Peoples R China.;Chinese Acad Sci, Inst Modern Phys, Lanzhou, Peoples R China.;Chinese Acad Sci, Univ Chinese Acad Sci, Beijing, Peoples R China.
关键词：
sweet sorghum juice;Clostridium tyrobutyricum TGL-A236;bio-butyric acid;qRT-PCR;pathway and process enrichment;protein homology modeling;protein cavity
摘要：
Introduction: Sweet sorghum juice is a typical production feedstock for natural, eco-friendly sweeteners and beverages. Clostridium tyrobutyricum is one of the widely used microorganisms in the food industry, and its principal product, bio-butyric acid is an important food additive. There are no published reports of Clostridium tyrobutyricum producing butyric acid using SSJ as the sole substrate without adding exogenous substances, which could reach a food-additive grade. This study focuses on tailoring a cost-effective, safe, and sustainable process and strategy for their production and application. Methods: This study modeled the enzymolysis of non-reducing sugars via the first/second-order kinetics and added food-grade diatomite to the hydrolysate. Qualitative and quantitative analysis were performed using high-performance liquid chromatography, gas chromatography-mass spectrometer, full-scale laser diffraction method, ultra-performance liquid chromatography-tandem mass spectrometry, the cell double-staining assay, transmission electron microscopy, and Oxford nanopore technology sequencing. Quantitative real-time polymerase chain reaction, pathway and process enrichment analysis, and homology modeling were conducted for mutant genes. Results: The treated sweet sorghum juice showed promising results, containing 70.60 g/L glucose and 63.09 g/L fructose, with a sucrose hydrolysis rate of 98.29% and a minimal sucrose loss rate of 0.87%. Furthermore, 99.62% of the colloidal particles and 82.13% of the starch particles were removed, and the concentrations of hazardous substances were effectively reduced. A food microorganism Clostridium tyrobutyricum TGL-A236 with deep utilization value was developed, which showed superior performance by converting 30.65% glucose and 37.22% fructose to 24.1364 g/L bio-butyric acid in a treated sweet sorghum juice (1:1 dilution) fermentation broth. This titer was 2.12 times higher than that of the original strain, with a butyric acid selectivity of 86.36%. Finally, the Genome atlas view, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and evolutionary genealogy of genes: Non-supervised Orthologous (eggNOG) functional annotations, three-dimensional structure and protein cavity prediction of five non-synonymous variant genes were obtained. Conclusion: This study not only includes a systematic process flow and in-depth elucidation of relevant mechanisms but also provides a new strategy for green processing of food raw materials, improving food microbial performance, and ensuring the safe production of food additives.
摘要：
In the actual industrial production process, the efficient biosynthesis and secretion of Monascus pigments (MPs) tend to take place under abiotic stresses, which often result in an imbalance of cell homeostasis. The present study aimed to thoroughly describe the changes in lipid profiles in Monascus purpureus by absolute quantitative lipidomics and tandem mass tag-based quantitative proteomics. The results showed that ammonium chloride stress (15 g/L) increased MP production while inhibiting ergosterol biosynthesis, leading to an imbalance in membrane lipid homeostasis in Monascus. In response to the imbalance of lipid homeostasis, the regulation mechanism of phospholipids in Monascus was implemented, including the inhibition of lysophospholipids production, maintenance of the ratio of PC/PE, and improvement of the biosynthesis of phosphatidylglycerol, phosphatidylserine, and cardiolipin with high saturated and long carbon chain fatty acids through the CDP-DG pathway rather than the Kennedy pathway. The inhibition of lysophospholipid biosynthesis was attributed to the upregulated expression of protein and its gene related to lysophospholipase NTE1, while maintenance of the PC/PE ratio was achieved by the upregulated expression of protein and its gene related to CTP: phosphoethanolamine cytidylyltransferase and phosphatidylethanolamine N-methyltransferase in the Kennedy pathway. These findings provide insights into the regulation mechanism of MP biosynthesis from new perspectives.IMPORTANCEMonascus is important in food microbiology as it produces natural colorants known as Monascus pigments (MPs). The industrial production of MPs has been achieved by liquid fermentation, in which the nitrogen source (especially ammonium chloride) is a key nutritional parameter. Previous studies have investigated the regulatory mechanisms of substance and energy metabolism, as well as the cross-protective mechanisms in Monascus in response to ammonium chloride stress. Our research in this work demonstrated that ammonium chloride stress also caused an imbalance of membrane lipid homeostasis in Monascus due to the inhibition of ergosterol biosynthesis. We found that the regulation mechanism of phospholipids in Monascus was implemented, including inhibition of lysophospholipids production, maintenance of the ratio of PC/PE, and improvement of biosynthesis of phosphatidylglycerol, phosphatidylserine, and cardiolipin with high saturated and long carbon chain fatty acids through the CDP-DG pathway. These findings further refine the regulatory mechanisms of MP production and secretion.
作者机构：
[罗凡; 杜孟浩; 方学智] Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China;[钟海雁] School of Food Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, China;[王龙祥] Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China<&wdkj&>School of Food Science and Technology, Central South University of Forestry and Technology, Changsha, 410004, China
作者机构：
[罗凡; 方学智; 杜孟浩; 胡立松] Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China;[龙奇志; 钟海雁] College of Food Science & Project Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[许晓君] Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, China<&wdkj&>College of Food Science & Project Engineering, Central South University of Forestry and Technology, Changsha, 410004, China
作者机构：
[王龙祥; 钟海雁] School of Food Science and Technology, Central South University of Forestry and Technology, Changsha;410004, China;[罗凡; 杜孟浩; 方学智] Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou;311400, China;[王龙祥] 410004, China <&wdkj&> Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou
摘要：
The advancement of biosensing has led to increased demands for precise target recognition and highly sensitive detection. Nanomaterials have emerged as indispensable contributors to this development process. Concurrently, the CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated system) also has surfaced as a novel tool that brings new prospects to the field of biosensing. Its notable benefits include accurate recognition, rapid response, ease of operation, and cost effectiveness. Significantly, the integration of nanomaterials and CRISPR/Cas exhibits immense potential for diverse applications. To enhance comprehension of biosensing research utilizing nanomaterials and CRISPR/Cas, this review comprehensively summarizes and analyzes the distinct functional roles of both components in biosensing approaches. The focus lies on exploring the applications of various nanomaterials (such as metal nanoparticles, metal oxides, carbon nanomaterials, porous framework materials, and other nanomaterials) combined with CRISPR/Cas in the biosensing field. Finally, the review discusses the challenges encountered and outlines future directions, providing valuable insights reference for the development of novel biosensing methodologies.
