Journal of Industrial Microbiology & Biotechnology最新文献

Perkinsus marinus (Perkinsea) is an osmotrophic facultative intracellular marine protozoan responsible for "Dermo" disease in the eastern oyster, Crassostrea virginica. In 1993 in vitro culture of P. marinus was developed in the absence of host cells. Compared to most intracellular protozoan parasites, the availability of P. marinus to grow in the absence of host cells has provided the basis to explore its use as a heterologous expression system. As the genetic toolbox is becoming available, there is also the need for larger-scale cultivation and lower-cost media formulations. Here, we took an industrial approach to scaled-up growth from a small culture flask to bioreactors, which required developing new cultivation parameters, including aeration, mixing, pH, temperature control, and media formulation. Our approach also enabled more real-time data collection on growth. The bioreactor cultivation method showed similar or accelerated growth rates of P. marinus compared to culture in T-flasks. Redox measurements indicated sufficient oxygen availability throughout the cultivation. Replacing fetal bovine serum with chicken serum showed no differences in the growth rate and a 60% reduction in the medium cost. This study opens the door to furthering P. marinus as a valid heterologous expression system by showing the ability to grow in bioreactors.

One-sentence summary: Perkinsus marinus, a microbial parasite of oysters that could be useful for developing vaccines for humans, has been shown to grow well in laboratory equipment that can be expanded to commercial scale using a less expensive growth formula than usual laboratory practice.

Sharomyces cerevisiae is currently one of the most important foreign gene expression systems. S. cerevisiae is an excellent host for high-value metabolite cell factories due to its advantages of simplicity, safety, and nontoxicity. A promoter, as one of the basic elements of gene transcription, plays an important role in regulating gene expression and optimizing metabolic pathways. Promoters control the direction and intensity of transcription, and the application of promoters with different intensities and performances will largely determine the effect of gene expression and ultimately affect the experimental results. Due to its significant role, there have been many studies on promoters for decades. While some studies have explored and analyzed new promoters with different functions, more studies have focused on artificially modifying promoters to meet their own scientific needs. Thus, this article reviews current research on promoter engineering techniques and related natural promoters in S. cerevisiae. First, we introduce the basic structure of promoters and the classification of natural promoters. Then, the classification of various promoter strategies is reviewed. Finally, by grouping related articles together using various strategies, this review anticipates the future development direction of promoter engineering.

This research aimed to assess how the partial removal of carbon dioxide affects fermentations to provide a better understanding of how the manipulation of carbon dioxide concentration can be used to optimize industrial fermentations. To achieve this, fermentation kinetics, fermentation metabolic products, and yeast stress indicators were analyzed throughout ongoing brewing fermentations conducted under partial vacuum with atmospheric pressure controls. The partial vacuum reduced the solubility of carbon dioxide in the media and decreased the time necessary to reach carbon dioxide saturation. The effect was an increased rate of fermentation, and significantly more viable cells produced under vacuum pressure compared to controls. Ethanol, glycerol, and volatile organic compound concentrations were all significantly increased under partial vacuum, while indicators of yeast stress (trehalose) were reduced. Additionally, as the number of yeast cells was higher under partial vacuum, less sugar was consumed per volume of yeast cell. This study measured fermentation kinetics, metabolic products, and yeast health to holistically assess the effect of partial vacuum during a batch fermentation and found significant differences in each that can be individually exploited by researchers and industry.

Summary: An exploration of batch yeast fermentation in a low-pressure environment, with a focus on the health and productivity of the yeast cells.

Microbial bioproduction often faces challenges related to populational heterogeneity, where cells exhibit varying biosynthesis capabilities. Bioproduction heterogeneity can stem from genetic and non-genetic factors, resulting in decreased titer, yield, stability, and reproducibility. Consequently, understanding and controlling bioproduction heterogeneity are crucial for enhancing the economic competitiveness of large-scale biomanufacturing. In this review, we provide a comprehensive overview of current understandings of the various mechanisms underlying bioproduction heterogeneity. Additionally, we examine common strategies for controlling bioproduction heterogeneity based on these mechanisms. By implementing more robust measures to mitigate heterogeneity, we anticipate substantial enhancements in the scalability and stability of bioproduction processes.

One-sentence summary: This review summarizes current understandings of different mechanisms of bioproduction heterogeneity and common control strategies based on these mechanisms.

Historically, bacteria of the phylum, Actinobacteria have been a very prominent source of bioactive compounds for drug discovery. Among the actinobacterial genera, Micrococcus has not generally been prioritized in the search for novel drugs. The bacteria in this genus are known to have very small genomes (generally < 3 Mb). Actinobacteria with small genomes seldom contain the well-characterized biosynthetic gene clusters such as those encoding polyketide synthases and nonribosomal peptide synthetases that current genome mining algorithms are optimized to detect. Nevertheless, there are many reports of substantial pharmaceutically relevant bioactivity of Micrococcus extracts. On the other hand, there are remarkably few descriptions of fully characterized and structurally elucidated bioactive compounds from Micrococcus spp. This review provides a comprehensive summary of the bioactivity of Micrococcus spp. that encompasses antibacterial, antifungal, cytotoxic, antioxidant, and anti-inflammatory activities. This review uncovers the considerable biosynthetic potential of this genus and highlights the need for a re-examination of these bioactive strains, with a particular emphasis on marine isolates, because of their potent bioactivity and high potential for encoding unique molecular scaffolds.

Biogenic synthesis of inorganic nanomaterials has been demonstrated for both wild and engineered bacterial strains. In many systems the nucleation and growth of nanomaterials is poorly controlled and requires concentrations of heavy metals toxic to living cells. Here, we utilized the tools of synthetic biology to engineer a strain of Escherichia coli capable of synthesizing cadmium sulfide nanoparticles from low concentrations of reactants with control over the location of synthesis. Informed by simulations of bacterially-assisted nanoparticle synthesis, we created a strain of E. coli expressing a broad-spectrum divalent metal transporter, ZupT, and a synthetic CdS nucleating peptide. Expression of ZupT in the outer membrane and placement of the nucleating peptide in the periplasm focused synthesis within the periplasmic space and enabled sufficient nucleation and growth of nanoparticles at sub-toxic levels of the reactants. This strain synthesized internal CdS quantum dot nanoparticles with spherical morphology and an average diameter of approximately 3.3 nm.

One-sentence summary: Expression of a metal ion transporter regulates synthesis of cadmium sulfide nanoparticles in bacteria.

Genkwanin has various significant roles in nutrition, biomedicine, and pharmaceutical biology. Previously, this compound was chiefly produced by plant-originated extraction or chemical synthesis. However, due to increasing concern and demand for safe food and environmental issues, the biotechnological production of genkwanin and other bioactive compounds based on safe, cheap, and renewable substrates has gained much interest. This paper described recombinant Escherichia coli-based co-culture engineering that was reconstructed for the de novo production of genkwanin from d-glucose. The artificial genkwanin biosynthetic chain was divided into 2 modules in which the upstream strain contained the genes for synthesizing p-coumaric acid from d-glucose, and the downstream module contained a gene cluster that produced the precursor apigenin and the final product, genkwanin. The Box-Behnken design, a response surface methodology, was used to empirically model the production of genkwanin and optimize its productivity. As a result, the application of the designed co-culture improved the genkwanin production by 48.8 ± 1.3 mg/L or 1.7-fold compared to the monoculture. In addition, the scale-up of genkwanin bioproduction by a bioreactor resulted in 68.5 ± 1.9 mg/L at a 48 hr time point. The combination of metabolic engineering and fermentation technology was therefore a very efficient and applicable approach to enhance the production of other bioactive compounds.

Plastic waste is an outstanding environmental thread. Poly(ethylene terephthalate) (PET) is one of the most abundantly produced single-use plastics worldwide, but its recycling rates are low. In parallel, additive manufacturing is a rapidly evolving technology with wide-ranging applications. Thus, there is a need for a broad spectrum of polymers to meet the demands of this growing industry and address post-use waste materials. This perspective article highlights the potential of designing microbial cell factories to upcycle PET into functionalized chemical building blocks for additive manufacturing. We present the leveraging of PET hydrolyzing enzymes and rewiring the bacterial C2 and aromatic catabolic pathways to obtain high-value chemicals and polymers. Since PET mechanical recycling back to original materials is cost-prohibitive, the biochemical technology is a viable alternative to upcycle PET into novel 3D printing materials, such as replacements for acrylonitrile butadiene styrene. The presented hybrid chemo-bio approaches potentially enable the manufacturing of environmentally friendly degradable or higher-value high-performance polymers and composites and their reuse for a circular economy.

One-sentence summary: Biotransformation of waste PET to high-value platform chemicals for additive manufacturing.

Eunicellane diterpenoids are a remarkable family of terpene natural products and have been of high interest for over five decades. Widely distributed in soft corals and rare in plants, eunicellanes were also recently identified in actinobacteria. These terpenoids have foundational 6/10-bicyclic frameworks that are frequently oxidized into structures containing transannular ether bridges. Interest in their unique structures and promising biological activities, such as the paclitaxel-like activities of eleutherobin and the sarcodictyins, has led to advancements in natural product isolation, total synthesis, medicinal chemistry, and drug lead development. Until recently, however, there was little known about the biosynthesis and enzymology of these natural products, but several recent studies in both bacteria and coral have opened up the field. This review summarizes recent advancements in the biosynthesis and enzymology of eunicellane diterpenoids and highlights future research prospects in the field.

One-sentence summary: A summary of recent advancements in the biosynthesis and enzymology of eunicellane diterpenoids, a structurally unique and biologically active family of natural products found in coral, plants, and bacteria.