Escherichia coli is the best-known model for the biotechnological production of many biotechnological products, including housekeeping and heterologous primary and secondary metabolites and recombinant proteins, and is an efficient biofactory model to produce biofuels to nanomaterials. Glucose is the primary substrate used as the carbon source for laboratory and industrial cultivation of E. coli for production purposes. Efficient growth and associated production and yield of desired products depend on the efficient sugar transport capabilities, sugar catabolism through the central carbon catabolism, and the efficient carbon flux through specific biosynthetic pathways. The genome of E. coli MG1655 is 4,641,642 bp, corresponding to 4702 genes encoding 4328 proteins. The EcoCyc database describes 532 transport reactions, 480 transporters, and 97 proteins involved in sugar transport. Nevertheless, due to the high number of sugar transporters, E. coli uses preferentially few systems to grow in glucose as the sole carbon source. E. coli nonspecifically transports glucose from the extracellular medium into the periplasmic space through the outer membrane porins. Once in periplasmic space, glucose is transported into the cytoplasm by several systems, including the phosphoenolpyruvate-dependent phosphotransferase system (PTS), the ATP-dependent cassette (ABC) transporters, and the major facilitator (MFS) superfamily proton symporters. In this contribution, we review the structures and mechanisms of the E. coli central glucose transport systems, including the regulatory circuits recruiting the specific use of these transport systems under specific growing conditions. Finally, we describe several successful examples of transport engineering, including introducing heterologous and non-sugar transport systems for producing several valuable metabolites.

Pulque is the most-studied traditional Mexican alcoholic beverage prepared by fermentation of the fresh sap (aguamiel, AM) extracted from different Agave species (maguey) cultivated for pulque production. This beverage has been produced mainly in the Central Mexico Plateau since pre-Columbian times. In this contribution, we report the analysis of the bacterial and fungal diversity through 16S rRNA gene V3–V4 fragment amplicon and ITSR1 sequencing associated with the tissue of the walls (metzal) of the cavity or cajete, where the sap accumulates in producing plants for its daily extraction, in AM, and during four fermentation stages for pulque production. The results led to determining which microorganisms detected in the plant tissue are present in AM and maintained during the fermentation process. The results showed that eight bacterial OTUs (Lactobacillus, Leuconostoc, Weisella, Lactococcus, Acetobacter, Gluconobacter, Zymomonas, and Obesumbacterium) and five fungal OTUs (Kazachstania, Kluyveromyces, Saccharomyces, Hanseniaspora, and the OTU O_Saccharomycetales) were present from metzal to AM and during all the stages of the fermentation analyzed. The detected diversity was considered the microbial core for pulque fermentation, comprising up to ~84% of the total bacterial diversity and up to ~99.6% of the fungal diversity detected in the pulque produced from three plants of A. salmiana from the locality of Huitzilac, Morelos, Mexico. This study provides relevant information on the potential microorganisms responsible for pulque fermentation, demonstrating that the core of microorganisms is preserved throughout the elaboration process and their association with the AM and fermented beverage physiochemical profile.

The aminoshikimic acid (ASA) pathway comprises a series of reactions resulting in the synthesis of 3-amino-5-hydroxybenzoic acid (AHBA), present in bacteria such as Amycolatopsis mediterranei and Streptomyces. AHBA is the precursor for synthesizing the mC₇N units, the characteristic structural component of ansamycins and mitomycins antibiotics, compounds with important antimicrobial and anticancer activities. Furthermore, aminoshikimic acid, another relevant intermediate of the ASA pathway, is an attractive candidate for a precursor for oseltamivir phosphate synthesis, the most potent anti-influenza neuraminidase inhibitor treatment of both seasonal and pandemic influenza. This review discusses the relevance of the key intermediate AHBA as a scaffold molecule to synthesize diverse ansamycins and mitomycins. We describe the structure and control of the expression of the model biosynthetic cluster rif in A. mediterranei to synthesize ansamycins and review several current pharmaceutical applications of these molecules. Additionally, we discuss some relevant strategies developed for overproducing these chemicals, focusing on the relevance of the ASA pathway intermediates kanosamine, AHAB, and ASA.

The aromatic compound p-coumaric acid (p-CA) is a secondary metabolite produced by plants. This aromatic acid and derived compounds have positive effects on human health, so there is interest in producing them in biotechnological processes with recombinant Escherichia coli strains. To determine the physiologic response of E. coli W3110 to p-CA, dynamic expression analysis of selected genes fused to a fluorescent protein reporter as well as RNA-seq and RT-qPCR were performed. The observed transcriptional profile revealed the induction of genes involved in functions related to p-CA active export, synthesis of cell wall and membrane components, synthesis of amino acids, detoxification of formaldehyde, phosphate limitation, acid stress, protein folding and degradation. Downregulation of genes encoding proteins involved in energy production, carbohydrate import and metabolism, as well as several outer and plasma membrane proteins was detected. This response is indicative of cell envelope damage causing the leakage of intracellular components including amino acids and phosphate-containing compounds. The cellular functions responding to p-CA that were identified in this study will help in defining targets for production strains improvement.

The intracellular [ATP]/[ADP] ratio is crucial for Escherichia coli’s cellular functions, impacting transport, phosphorylation, signaling, and stress responses. Overexpression of F₁-ATPase genes in E. coli increases glucose consumption, lowers energy levels, and triggers transcriptional responses in central carbon metabolism genes, particularly glycolytic ones, enhancing carbon flux. In this contribution, we report the impact of the perturbation of the energetic level in a PTS⁻ mutant of E. coli by modifying the [ATP]/[ADP] ratio by uncoupling the cytoplasmic activity of the F₁ subunit of the ATP synthase. The disruption of [ATP]/[ADP] ratio in the evolved strain of E. coli PB12 (PTS⁻) was achieved by the expression of the atpAGD operon encoding the soluble portion of ATP synthase F₁-ATPase (strain PB12AGD⁺). The analysis of the physiological and metabolic response of the PTS⁻ strain to the ATP disruption was determined using RT–qPCR of 96 genes involved in glucose and acetate transport, glycolysis and gluconeogenesis, pentose phosphate pathway (PPP), TCA cycle and glyoxylate shunt, several anaplerotic, respiratory chain, and fermentative pathways genes, sigma factors, and global regulators. The apt mutant exhibited reduced growth despite increased glucose transport due to decreased energy levels. It heightened stress response capabilities under glucose-induced energetic starvation, suggesting that the carbon flux from glycolysis is distributed toward the pentose phosphate and the Entner–Duodoroff pathway with the concomitant. Increase acetate transport, production, and utilization in response to the reduction in the [ATP]/[ADP] ratio. Upregulation of several genes encoding the TCA cycle and the glyoxylate shunt as several respiratory genes indicates increased respiratory capabilities, coupled possibly with increased availability of electron donor compounds from the TCA cycle, as this mutant increased respiratory capability by 240% more than in the PB12. The reduction in the intracellular concentration of cAMP in the atp mutant resulted in a reduced number of upregulated genes compared to PB12, suggesting that the mutant remains a robust genetic background despite the severe disruption in its energetic level.

We report the complete genome and the plasmid (F' episome) sequences of Escherichia coli JM101 assembled with a combination of Nanopore and Illumina data. The resulting genome is a single contig of 4,524,963 bp, and the plasmid consists of a single contig of 197,186 bp.