Advances in biochemical engineering/biotechnology最新文献

Plant tissue culture has evolved in the last decades with several types of cultures being developed to promote a more sustainable food production system. Moreover, these cultures can be applied for the production of relevant metabolites with medicinal potential, thus contributing to nutrition and healthcare. Importantly, plant micropropagation has enabled agricultural expansion and tissue culture has emerged as a promising production alternative for several plants and their metabolites in the food, cosmetic, and pharmaceutical industries. Plant tissue cultures present several advantages over conventional propagation techniques as they are season independent, enabling a continuous supply of the plants/compounds of interest, with the guarantee of high phytosanitary quality. In addition, genetic uniformity is generally maintained, thus reducing chemical variability that can compromise safety and efficacy. Nevertheless, despite their undeniable potential, with many researchers focusing on new strategies to improve production yield in cell cultures, such as with the use of elicitors or resorting to metabolomics engineering, an effective and lucrative large-scale production has yet to be obtained. Indeed, only a few compounds with market value are produced in this regard and several limitations such as contaminations, low culture yield and production costs still need to be overcome in order to take advantage of the full potential of these techniques.

Microarrays are widely utilized in bioanalysis. Electrochemical biosensing techniques are often applied in microarray-based assays because of their simplicity, low cost, and high sensitivity. In such systems, the electrodes and sensing elements are arranged in arrays, and the target analytes are detected electrochemically. These sensors can be utilized for high-throughput bioanalysis and the electrochemical imaging of biosamples, including proteins, oligonucleotides, and cells. In this chapter, we summarize recent progress on these topics. We categorize electrochemical biosensing techniques for array detection into four groups: scanning electrochemical microscopy, electrode arrays, electrochemiluminescence, and bipolar electrodes. For each technique, we summarize the key principles and discuss the advantages, disadvantages, and bioanalysis applications. Finally, we present conclusions and perspectives about future directions in this field.

Pigments are intensely coloured compounds used in many industries to colour other materials. The demand for naturally synthesised pigments is increasing and their production can be incorporated into circular bioeconomy approaches. Natural pigments are produced by bacteria, cyanobacteria, microalgae, macroalgae, plants and animals. There is a huge unexplored biodiversity of prokaryotic cyanobacteria which are microscopic phototrophic microorganisms that have the ability to capture solar energy and CO₂ and use it to synthesise a diverse range of sugars, lipids, amino acids and biochemicals including pigments. This makes them attractive for the sustainable production of a wide range of high-value products including industrial chemicals, pharmaceuticals, nutraceuticals and animal-feed supplements. The advantages of cyanobacteria production platforms include comparatively high growth rates, their ability to use freshwater, seawater or brackish water and the ability to cultivate them on non-arable land. The pigments derived from cyanobacteria and microalgae include chlorophylls, carotenoids and phycobiliproteins that have useful properties for advanced technical and commercial products. Development and optimisation of strain-specific pigment-based cultivation strategies support the development of economically feasible pigment biorefinery scenarios with enhanced pigment yields, quality and price. Thus, this chapter discusses the origin, properties, strain selection, production techniques and market opportunities of cyanobacterial pigments.

Cyanobacteria are promising microbial cell factories for the direct production of biochemicals and biofuels from CO₂. Through genetic and metabolic engineering, they can be modified to produce a variety of both natural and non-natural compounds. To enhance the yield of these products, various design strategies have been developed. In this chapter, strategies used to enhance metabolic fluxes towards common precursors used in biosynthesis, including pyruvate, acetyl-CoA, malonyl-CoA, TCA cycle intermediates, and aromatics, are discussed. Additionally, strategies related to cofactor availability and mixotrophic conditions for bioproduction are also summarize.

In vitro biotransformation (ivBT) refers to the use of an artificial biological reaction system that employs purified enzymes for the one-pot conversion of low-cost materials into biocommodities such as ethanol, organic acids, and amino acids. Unshackled from cell growth and metabolism, ivBT exhibits distinct advantages compared with metabolic engineering, including but not limited to high engineering flexibility, ease of operation, fast reaction rate, high product yields, and good scalability. These characteristics position ivBT as a promising next-generation biomanufacturing platform. Nevertheless, challenges persist in the enhancement of bulk enzyme preparation methods, the acquisition of enzymes with superior catalytic properties, and the development of sophisticated approaches for pathway design and system optimization. In alignment with the workflow of ivBT development, this chapter presents a systematic introduction to pathway design, enzyme mining and engineering, system construction, and system optimization. The chapter also proffers perspectives on ivBT development.

Technical advances in biotechnology have greatly accelerated the development of bottom-up synthetic biology. Unlike top-down approaches, bottom-up synthetic biology focuses on the construction of a minimal cell from scratch and the application of these principles to solve challenges. Cell-free protein synthesis (CFPS) systems provide minimal machinery for transcription and translation, from either a fractionated cell lysate or individual purified protein elements, thus speeding up the development of synthetic cell projects. In this review, we trace the history of the cell-free technique back to the first in vitro fermentation experiment using yeast cell lysate. Furthermore, we summarized progresses of individual cell mimicry modules, such as compartmentalization, gene expression regulation, energy regeneration and metabolism, growth and division, communication, and motility. Finally, current challenges and future perspectives on the field are outlined.

Cyanobacteria are the only prokaryotes performing oxygenic photosynthesis, a solar-driven process which allows them to obtain electrons from water to reduce and finally assimilate carbon dioxide. Consequently, they are in the spotlight of biotechnology as photoautotrophic cell factories to generate a large variety of chemicals and biofuels in a sustainable way. Recent progress in synthetic biology has enlarged the molecular toolset to genetically engineer the metabolism of cyanobacteria, mainly targeting common model strains, such as Synechocystis sp. PCC 6803, Synechococcus elongatus PCC 7942, Synechococcus sp. PCC 7002, or Anabaena sp. PCC 7120. Nevertheless, the accessibility and flexibility of engineering cyanobacteria is still somewhat limited and less predictable compared to other biotechnologically employed microorganisms.This chapter gives a broad overview of currently available methods for the genetic modification of cyanobacterial model strains as well as more recently discovered and promising species, such as Synechococcus elongatus PCC 11801. It comprises approaches based on homologous recombination, replicative broad-host-range or strain-specific plasmids, CRISPR/Cas, as well as markerless selection. Furthermore, common and newly introduced molecular tools for gene expression regulation are presented, comprising promoters, regulatory RNAs, genetic insulators like transcription terminators, ribosome binding sites, CRISPR interference, and the utilization of heterologous RNA polymerases. Additionally, potential DNA assembly strategies, like modular cloning, are described. Finally, considerations about post-translational control via protein degradation tags and heterologous proteases, as well as small proteins working as enzyme effectors are briefly discussed.

In order to obtain strains with targeted changes in genetic characteristics, molecular biology and genetic engineering techniques are used to integrate target gene fragments into the vector and transform them into recipient cells. Due to the different target genes and functional elements on the transformation plasmids, gene silencing, gene knockout, and gene overexpression can be carried out, which provides a new way to study the gene function of edible fungi. At present, the cloning vectors used in the transformation of edible fungi are modified by bacterial plasmids, among which pCAMBIA-1300 plasmid and pAN7 plasmid are the two most commonly used basic vectors. On this basis, some basic elements such as promoters, selective marker genes, and reporter genes were added to construct silencing vectors, knockout vectors, and overexpression vectors. At the same time, different expression vector systems are needed for different transformation methods. In this chapter, the main elements of the genetic system (promoters, screening markers), the current main genetic transformation methods (Agrobacterium-mediated transformation, liposome transformation, electroporation method), and the specific application of transformation were systematically summarized, which provides a reference for the study of the genetic system of edible fungi.

Great interest for large-scale production of medicinal mushroom biomass and various pharmaceutically active compounds production dictates the development of comprehensive technologies. Solid state and submerged cultivations in bioreactors represent the most promising technologies for fast and large amount production of medicinal fungi biomass and pharmaceutically active products for human and veterinary need. There are many stages from shaking culture studies to large-scale industrial production. Pilot-scale studies represent the bridge and the balance between the gap of laboratory and industrial scale. Therefore it is not a surprise that most of pilot-scale results and experiences remain uncovered industrial secrets. This chapter is an overview of available engineering achievements in submerged and solid-state cultivation experiences in pilot-scale bioreactors.

The survival of Homo sapiens is continually under threat from agencies capable of inflicting calamitous damage to the overall health and well-being of humankind. One strategy aimed at combatting this threat is focused on medicinal mushrooms and derivatives thereof. Mushrooms themselves have been consumed as part of the human diet for centuries, whereas 'mushroom nutriceuticals' is a more recently adopted term describing mushroom-derived products taken as dietary supplements to enhance general health and fitness. Among the most extensively studied pharmacologically active components of mushrooms are polysaccharides and polysaccharide-protein complexes, triterpenes, lectins, and fungal immunomodulatory proteins. Medicinal mushrooms have been credited with a wide range of therapeutic properties including antitumour/anti-cancer, antioxidant, hepatoprotective, anti-diabetic, antimicrobial, cholesterol-lowering and genoprotective activities as well as protection against atherosclerosis, cardiovascular, chronic inflammatory and autoimmune diseases, and neurodegenerative conditions. This review examines the past, present and future of medicinal mushroom development including the two legs concept for the mushroom industry and the pyramid model summarizing the various human applications of mushrooms. It considers numerous issues the industry needs to address to exploit fully the opportunities presented by the continued increasing demand for medicinal mushrooms, and by the future overall expansion of the medicinal mushroom movement.