Trends in biotechnology最新文献

Autologous or allogeneic platelet-derived extracellular vesicles (pEVs) show potential in enhancing tissue recovery and healing chronic wounds. pEVs promote neovascularization and cell migration while reducing inflammation, oxidative stress, and scarring. However, their efficacy in clinical settings is challenged by their susceptibility to washout by wound exudate. Hydrogel-based bandages are effective carriers that stabilize pEVs for optimal personalized wound care. These bandages can be tailored for easy removal to minimize damage to regenerated tissue and can incorporate antibacterial or moisture-retaining properties. Furthermore, the possibility of integrating sensors in the wound bed will enable a theragnostic approach to healing. This review explores advancements in pEV-loaded hydrogels and their potential for personalized clinical applications.

Many fermentation products inhibit their own microbial production, which complicates industrial-scale fermentation development for these products. When a product is volatile, this inhibition can be circumvented by removing product during fermentation through evaporation in a loop around the bioreactor. Microbes can survive this loop if its temperature is reduced using vacuum. Then, regrowing of microbes is not required. From a separation efficiency viewpoint, the evaporation loop should not use a single equilibrium stage, but a multistage vacuum distillation column. Such in situ product removal (ISPR) by vacuum distillation has hardly been recognized as an option, however. Costs for this product removal with subsequent purification are modest, even when product titers are low. A prerequisite is the use of advanced energy integration and heat pumping methods.

The dissemination of antibiotic resistance from environmental sources is a growing concern. Despite the widespread occurrence of antibiotic resistance transmission events, there are actually multiple obstacles in the ecosystem that restrict the flow of bacteria and genes, in particular nonnegligible biological barriers. How these ecological factors help combat the dissemination of antibiotic resistance and relevant antibiotic resistance-diminishing organisms (ARDOs) deserves further exploration. This review summarizes the factors that influence the growth, metabolism, and environmental adaptation of antibiotic-resistant bacteria (ARB) and restrict the horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs). Additionally, this review discusses the achievements in the application of ARDOs to improve biotechnology for wastewater and solid waste remediation while highlighting current challenges limiting their broader implementation.

Much attention has focused on understanding microbial interactions leading to stable co-cultures. In this work, substrate pulsing was performed to promote better control of the metabolic niches (MNs) corresponding to each species, leading to the continuous co-cultivation of diverse microbial organisms. We used a cell-machine interface, which allows adjustment of the temporal profile of two MNs according to a rhythm, ensuring the successive growth of two species, in our case, a yeast and a bacterium. The resulting approach, called 'automated adjustment of metabolic niches' (AAMN), was effective for stabilizing both cooperative and competitive co-cultures. AAMN can be considered an enabling technology for the deployment of co-cultures in bioprocesses, demonstrated here based on the continuous bioproduction of p-coumaric acid. The data accumulated suggest that AAMN could be used not only for a wider range of biological systems, but also to gain fundamental insights into microbial interaction mechanisms.

A multitude of plastic-depolymerizing microorganisms and enzymes have been discovered in the plastisphere. Identifying and engineering such microbial strains and enzymes necessitate robust and high-throughput screening strategies for developing effective microbial solutions to counter the plastic accumulation problem and decouple the reliance on fossil resources. This review covers new methods and approaches for the effective high-throughput screening of depolymerizing enzymes for various plastics, such as polyethylene terephthalate (PET), polyurethane (PU), and polylactic acid (PLA). We discuss the application scope of the existing methods, as well as potential developments and integration of screening techniques to identify and enhance plastic depolymerases. The prospects for screening a wider range of plastic depolymerases with the advances in biotechnology tools such as droplet microfluidics and biosensors are highlighted.

Engineering nitrogen fixation in cereals could reduce usage of chemical nitrogen fertilizers. Here, a nitrogenase biosynthesis pathway comprising 13 genes (nifB nifH nifD nifK nifE nifN nifX hesA nifV nifS nifU groES groEL) was introduced into rice by transforming multigene vectors and subsequently by sexual crossing between transgenic rice plants. Genome sequencing analysis revealed that 13 nif genes in F₄ hybrid rice lines L12-13 and L8-17 were inserted at two loci on rice chromosome 1. Eleven nitrogen fixation (Nif) proteins were produced and stable NifDK tetramer was formed in rice cytosol. NifH in rice cytosol was unstable and NifH-S18 was found to be a key residue that conferred susceptibility to proteinase degradation. NifH variants with Fe protein activity and resistance to plant endoproteinase cleavage were obtained. This study provides an efficient approach for introducing multiple nif genes into plants and also helps to pre-evaluate the stability of prokaryotic proteins in plant cytosol.

Microbial production of organic acids has been hindered by the poor acid tolerance of microorganisms and the high costs of waste salt reprocessing. The robustness of non-conventional microorganisms in an acidic environment makes it possible to produce organic acids at low pH and greatly simplifies downstream processing. In this review we discuss the environmental adaptability features of non-conventional yeasts, as well as the latest developments in genomic engineering strategies that have facilitated metabolic engineering of these strains. We also use selected examples of three-carbon (C3), C4, and C6 organic acids to illustrate the ongoing efforts and challenges of using non-conventional yeasts for organic acid production. This review provides theoretical guidance for the construction of highly robust organic acid producers.

Replicating the contractile function of arterial tissues in vitro requires precise control of cell alignment within 3D structures, a challenge that existing bioprinting techniques struggle to meet. In this study, we introduce the voxel-based embedded construction for tailored orientational replication (VECTOR) method, a voxel-based approach that controls cellular orientation and collective behavior within bioprinted filaments. By fine-tuning voxel vector magnitude and using an omnidirectional printing trajectory, we achieve structural mimicry at both the macroscale and the cellular alignment level. This dual-scale approach enhances vascular smooth muscle cell (VSMC) function by regulating contractile and synthetic pathways. The VECTOR method facilitates the construction of 3D arterial structures that closely replicate natural coronary architectures, significantly improving contractility and metabolic function. Moreover, the resulting multilayered arterial models (AMs) exhibit precise responses to pharmacological stimuli, similar to native arteries. This work highlights the critical role of structural mimicry in tissue functionality and advances the replication of complex tissues in vitro.

(Homo)acetogens, including Clostridium spp., represent an enigma in metabolic flexibility and diversity. Eubacterium callanderi KIST612 is an acetogen that produces n-butyrate with carbon monoxide (CO) as the carbon and energy source; however, the production route is unknown. Here, we report that its distinctive butyrate formation links to reductive acetate uptake, suggesting that acetate (the end-product) is reuptake, leading to a physiological advantage through NADH oxidation. Thus, we introduced an ethanol production pathway from acetyl-CoA as a competitive pathway for butyrate production. Consequently, the metabolic pathway in our mutants switched from acetogenesis to 'ethanologenesis', eliminating butyrate production and the uptake of previously produced acetate. The metabolic shifts occurred toward greater NADH oxidation, facilitating CO oxidation and productivity, which is a survival mechanism at the thermodynamic edge. This metabolic shift to a single product holds potential to revolutionize product separation strategies in synthetic gas (syngas)-based biorefineries.