The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide (CO₂) emissions, posing an ongoing threat to the ecological security of the Earth. Microbial electrosynthesis (MES) is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO₂ into high-value products. The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system. Therefore, this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system. The topics covered include inward extracellular electron transfer pathways, cathode materials, applied cathode potentials, catholyte pH, and reactor configuration. In addition, this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO₂ into high-value products via MES.

Terpenoids are widely used as medicines, flavors, and biofuels. However, the use of these natural products is largely restricted by their low abundance in native plants. Fortunately, heterologous biosynthesis of terpenoids in microorganisms offers an alternative and sustainable approach for efficient production. Various genome-editing technologies have been developed for microbial strain construction. Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein 9 (Cas9) is the most commonly used system owing to its outstanding efficiency and convenience in genome editing. In this review, the basic principles of CRISPR-Cas9 systems are briefly introduced and their applications in engineering bacteria for the production of plant-derived terpenoids are summarized. The aim of this review is to provide an overview of the current developments of CRISPR-Cas9-based genome-editing technologies in bacterial engineering, concluding with perspectives on the challenges and opportunities of these technologies.

Myxobacteria are well known for multicellular social behaviors and valued for biosynthesis of natural products. Myxobacteria social behaviors such as clumping growth severely hamper strain cultivation and genetic manipulation. Using Myxococcus xanthus DK1622, we engineered Hu04, which is deficient in multicellular behavior and pigmentation. Hu04, while maintaining nutritional growth and a similar metabolic background, exhibits improved dispersed growth, streamlining operational procedures. It achieves high cell densities in culture and is promising for synthetic biology applications.

The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis. Recently, Uppalapati et al. revealed a unique dual function of the Gifsy-1 prophage terminase in Salmonella enterica: it acts as a transfer ribonuclease (tRNase) under oxidative stress. The Gifsy-1 prophage terminase targets and fragments tRNA^Leu to halt translation and temporarily impairs bacterial growth when exposed to high levels of ROS generated by the host immune cells. This response not only preserves genomic integrity by facilitating DNA repair but also inhibits prophage mobilization, thereby aiding in bacterial survival within vertebrate hosts. This study highlights a novel intersection between phage biology and bacterial adaptive strategies.

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of developing novel vaccines. An ideal vaccine should trigger an intense immune reaction without causing significant side effects. In this study we found that substitution of tryptophan located in the cores of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protein structures with certain smaller amino acids resulted in variants with melting temperatures of 33-37 °C. An enzyme activity assay indicated that the proteolytic activity of the main proteinase (3CL^pro) decreased sharply when the environmental temperature exceeded the melting temperature, implying that other protein variants may lose most of their functions under the same conditions. This finding suggests that a virus variant containing engineered proteins with melting temperatures of 33-37 °C may only be functional in the upper respiratory tract where the temperature is about 33 °C, but will be unable to invade internal organs, which maintain temperatures above 37 °C, thus making it possible to construct temperature-sensitive attenuated vaccines.

The biotechnological industry faces a crucial demand for novel bioactive compounds, particularly antimicrobial agents, to address the rising challenge of bacterial resistance to current available antibiotics. Traditional strategies for cultivating naturally occurring microorganisms often limit the discovery of novel antimicrobial producers. This study presents a protocol for targeted selection of bacterial strains using the supernatant of Paenibacillus elgii, which produces abundant signal molecules and antimicrobial peptides. Soil samples were inoculated in these enriched culture media to selectively cultivate bacteria resistant to the supernatant, indicating their potential to produce similar compounds. The bacterial strains isolated through this method were assessed for their antibacterial activity. In addition, the functional annotation of the genome of one of these strains revealed several gene clusters of biotechnological interest. This study highlights the effectiveness of using this approach for selective cultivation of microorganisms with potential for biotechnological applications.

A novel cellulolytic bacterial strain, ROBY, was isolated from a bovine rumen sample using the enrichment culture method. This isolate was found to be Acinetobacter pittii, with >99 % similarity according to 16S rRNA gene sequence analysis. The potential use of this strain in combination with doxorubicin (Dox)-integrated cellulose nanoparticles (Dox-CNPs) was evaluated as a proof-of-concept study for the further development of this approach as a novel controlled-release drug delivery strategy. The isolate can utilize CNPs as the sole carbon source for growth and degrade both Dox-CNPs and empty CNPs with high efficiency. Extracellular cellulases isolated from bacteria may also be used to trigger Dox release. The results also demonstrated that the release of Dox into the environment due to nanoparticle degradation in the samples incubated with Dox-CNPs significantly affected bacterial cell viability (∼75 % decrease), proving the release of Dox due to bacterial cellulase activity and suggesting the great potential of this approach for further development.

Tigecycline serves as a critical “final-resort” antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited. The increasing prevalence of tigecycline resistance, particularly among Gram-negative bacteria, is a major concern. Various mechanisms have been identified as contributors to tigecycline resistance, including upregulation of nonspecific Resistance Nodulation Division (RND) efflux pumps due to mutations in transcriptional regulators, enzymatic modification of tigecycline by monooxygenase enzymes, and mutations affecting tigecycline binding sites. This review aims to consolidate our understanding of tigecycline resistance mechanisms in Gram-negative bacteria and offer insights and perspectives for further drug development.