Detection and characterization of a thermophilic biotin biosynthetic enzyme, 7-keto-8-aminopelargonic acid synthase, from various thermophiles

Advances and prospects in microbial production of biotin

Biotin, serving as a coenzyme in carboxylation reactions, is a vital nutrient crucial for the natural growth, development, and overall well-being of both humans and animals. Consequently, biotin is widely utilized in various industries, including feed, food, and pharmaceuticals. Despite its potential advantages, the chemical synthesis of biotin for commercial production encounters environmental and safety challenges. The burgeoning field of synthetic biology now allows for the creation of microbial cell factories producing bio-based products, offering a cost-effective alternative to chemical synthesis for biotin production. This review outlines the pathway and regulatory mechanism involved in biotin biosynthesis. Then, the strategies to enhance biotin production through both traditional chemical mutagenesis and advanced metabolic engineering are discussed. Finally, the article explores the limitations and future prospects of microbial biotin production. This comprehensive review not only discusses strategies for biotin enhancement but also provides in-depth insights into systematic metabolic engineering approaches aimed at boosting biotin production.

Analysis of In Vivo Transcriptome of Intracellular Bacterial Pathogen Salmonella enterica serovar Typhmurium Isolated from Mouse Spleen

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important intracellular pathogen that poses a health threat to humans. This study tries to clarify the mechanism of Salmonella survival and reproduction in the host. In this study, high-throughput sequencing analysis was performed on RNA extracted from the strains isolated from infected mouse spleens and an S. Typhimurium reference strain (ATCC 14028) based on the BGISEQ-500 platform. A total of 1340 significant differentially expressed genes (DEGs) were screened. Functional annotation revealed DEGs associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Through data mining and literature retrieval, 26 of the 58 upregulated DEGs (FPKM > 10) were not reported to be related to the adaptation to intracellular survival and were classified as candidate key genes (CKGs) for survival and proliferation in vivo. Our data contribute to our understanding of the mechanisms used by Salmonella to regulate virulence gene expression whilst replicating inside mammalian cells.

High temperature-induced proteomic and metabolomic profiles of a thermophilic Bacillus manusensis isolated from the deep-sea hydrothermal field of Manus Basin

Thermophiles are organisms that grow optimally at 50 °C-80 °C and studies on the survival mechanisms of thermophiles have drawn great attention. Bacillus manusensis S50-6 is the type strain of a new thermophilic species isolated from hydrothermal vent in Manus Basin. In this study, we examined the growth and global responses of S50-6 to high temperature on molecular level using multi-omics method (genomics, proteomics, and metabolomics). S50-6 grew optimally at 50 °C (Favorable, F) and poorly at 65 °C (Non-Favorable, NF); it formed spores at F but not at NF condition. At NF condition, S50-6 formed long filaments containing undivided cells. A total of 1621 proteins were identified at F and NF conditions, and 613 proteins were differentially expressed between F and NF. At NF condition, proteins of glycolysis, rRNA mature and modification, and DNA/protein repair were up-regulated, whereas proteins of sporulation and amino acid/nucleotide metabolism were down-regulated. Consistently, many metabolites associated with amino acid and nucleotide metabolic processes were down-regulated at NF condition. Our results revealed molecular strategies of deep-sea B. manusensis to survive at unfavorable high temperature and provided new insights into the thermotolerant mechanisms of thermophiles. SIGNIFICANCE: In this study, we systematically characterized the genomic, proteomic and metabolomic profiles of a thermophilic deep-sea Bacillus manusensis under different temperatures. Based on these analysis, we propose a model delineating the global responses of B. manusensis to unfavorable high temperature. Under unfavorable high temperature, glycolysis is a more important energy supply pathway; protein synthesis is subjected to more stringent regulation by increased tRNA modification; protein and DNA repair associated proteins are enhanced in production to promote heat survival. In contrast, energy-costing pathways, such as sporulation, are repressed, and basic metabolic pathways, such as amino acid and nucleotide metabolisms, are slowed down. Our results provide new insights into the thermotolerant mechanisms of thermophilic Bacillus.