Critical Reviews in Biotechnology最新文献

Cellulases and xylanases are plant cell wall-degrading enzymes (CWDEs) that are critical to sustainable bioproduction based on renewable lignocellulosic biomass to reduce carbon dioxide emission. Currently, these enzymes are mainly produced from filamentous fungi, especially Trichoderma reesei and Penicillium oxalicum. However, an in-depth comparison of these two producers has not been performed. Although both P. oxalicum and T. reesei harbor CWDE systems, they exhibit distinct features regulating the production of these enzymes, mainly through different transcriptional regulatory networks. This review presents the strikingly different modes of genome-wide regulation of cellulase and xylanase biosynthesis in P. oxalicum and T. reesei, including sugar transporters, signal transduction cascades, transcription factors, chromatin remodeling, and three-dimensional organization of chromosomes. In addition, different molecular breeding approaches employed, based on the understanding of the regulatory networks, are summarized. This review highlights the existence of very different regulatory modes leading to the efficient regulation of CWDE production in filamentous fungi, akin to the adage that "every road leads to Rome." An understanding of this divergence may help further improvements in fungal enzyme production through the metabolic engineering and synthetic biology of certain fungal species.

In the food industry, despite the widespread use of interventions such as preservatives and thermal and non-thermal processing technologies to improve food safety, incidences of foodborne disease continue to happen worldwide, prompting the search for alternative strategies. Bacteriophages, commonly known as phages, have emerged as a promising alternative for controlling pathogenic bacteria in food. This review emphasizes the potential applications of phages in biological sciences, food processing, and preservation, with a particular focus on their role as biocontrol agents for improving food quality and preservation. By shedding light on recent developments and future possibilities, this review highlights the significance of phages in the food industry. Additionally, it addresses crucial aspects such as regulatory status and safety concerns surrounding the use of bacteriophages. The inclusion of up-to-date literature further underscores the relevance of phage-based strategies in reducing foodborne pathogenic bacteria's presence in both food and the production environment. As we look ahead, new phage products are likely to be targeted against emerging foodborne pathogens. This will further advance the efficacy of approaches that are based on phages in maintaining the safety and security of food.

Algae-derived protein has immense potential to provide high-quality protein foods for the expanding human population. To meet its potential, a broad range of scientific tools are required to identify optimal algal strains from the hundreds of thousands available and identify ideal growing conditions for strains that produce high-quality protein with functional benefits. A research pipeline that includes proteomics can provide a deeper interpretation of microalgal composition and biochemistry in the pursuit of these goals. To date, proteomic investigations have largely focused on pathways that involve lipid production in selected microalgae species. Herein, we report the current state of microalgal proteome measurement and discuss promising approaches for the development of protein-containing food products derived from algae.

Stress tolerance is a vital attribute for all living beings to cope with environmental adversities. IrrE (also named PprI) from Deinococcus radiodurans enhances resistance to extreme radiation stress by functioning as a global regulator, mediating the transcription of genes involved in deoxyribonucleic acid (DNA) damage response (DDR). The expression of IrrE augmented the resilience of various species to heat, radiation, oxidation, osmotic stresses and inhibitors, encompassing bacterial, fungal, plant, and mammalian cells. Moreover, IrrE was employed in a global regulator engineering strategy to broaden its applications in stress tolerance. The regulatory impacts of heterologously expressed IrrE have been investigated at the molecular and systems level, including the regulation of genes, proteins, modules, or pathways involved in DNA repair, detoxification proteins, protective molecules, native regulators and other aspects. In this review, we discuss the regulatory role and mechanism of IrrE in the antiradiation response of D. radiodurans. Furthermore, the applications and regulatory effects of heterologous expression of IrrE to enhance abiotic stress tolerance are summarized in particular.

The market size of biosurfactants (BSs) has been expanding at an extremely fast pace due to their broad application scope. Therefore, the re-construction of cell factories with modified genomic and metabolic profiles for desired industrial performance has been an intriguing aspect. Typical mutagenesis approaches generate huge mutant libraries, whereas a battery of specific, robust, and cost-effective high-throughput screening (HTS) methods is requisite to screen target strains for desired phenotypes. So far, only a few specialized HTS assays have been developed for BSs that were successfully applied to obtain anticipated mutants. The most important milestones to reach, however, continue to be: specificity, sensitivity, throughput, and the potential for automation. Here, we discuss important colorimetric and fluorometric HTS approaches for possible intervention on automated HTS platforms. Moreover, we explain current bottlenecks in developing specialized HTS platforms for screening high-yielding producers and discuss possible perspectives for addressing such challenges.

Plant growth and productivity are continually being challenged by a diverse array of abiotic stresses, including: water scarcity, extreme temperatures, heavy metal exposure, and soil salinity. A common theme in these stresses is the overproduction of reactive oxygen species (ROS), which disrupts cellular redox homeostasis causing oxidative damage. Ascorbic acid (AsA), commonly known as vitamin C, is an essential nutrient for humans, and also plays a crucial role in the plant kingdom. AsA is synthesized by plants through the d-mannose/l-galactose pathway that functions as a powerful antioxidant and protects plant cells from ROS generated during photosynthesis. AsA controls several key physiological processes, including: photosynthesis, respiration, and carbohydrate metabolism, either by acting as a co-factor for metabolic enzymes or by regulating cellular redox-status. AsA's multi-functionality uniquely positions it to integrate and recalibrate redox-responsive transcriptional/metabolic circuits and essential biological processes, in accordance to developmental and environmental cues. In recognition of this, we present a systematic overview of current evidence highlighting AsA as a central metabolite-switch in plants. Further, a comprehensive overview of genetic manipulation of genes involved in AsA metabolism has been provided along with the bottlenecks and future research directions, that could serve as a framework for designing "stress-smart" crops in future.

Statins are the most prescribed drug for regulating the high cholesterol level in the blood, which can lead to severe complications, such as cardiovascular diseases and other health complications. A wide range of analytical techniques have been employed for the quantification of statins from various origins, including fermentation derived (lovastatin, pravastatin, and compactin), semi-synthetic (simvastatin), and synthetic (atorvastatin, rosuvastatin, and fluvastatin) routes. The presence of more than one structural form and structural analogue generated in the biosynthesis pathway, as well as reaction intermediates and macromolecules in the clinical sample, complicates the quantification of statins. Furthermore, significant concentrations of statins in environmental samples pose serious health and ecology hazards, and estimating statins in those diluted samples is extremely difficult. On the other hand, the: cost, accurate estimation of the desired one from other structural forms, sample complexity, time, limits of detection and quantification, were major criteria distinguishing the usability of each technique. As a result, the current manuscript focuses on analytical techniques such as molecular spectroscopy (normal and derivatives UV-Visible spectrophotometer), chromatography (TLC, HP-TLC, HPLC, GC, swing column, micellar, and supercritical fluid), mass spectroscopy (HPLC-MS/MS and GC-MS/MS), sequential flow injection, capillary electrophoresis, and cyclic voltammetry, as well as their: optimal operating conditions, limits of detection and quantification, advancements, and limitations. Furthermore, various online and offline sample preparations (precipitation, solid phase extraction, liquid-liquid extraction, and micellar extraction) have been highlighted as an essential pretreatment technique to avoid the interference caused by structural analogues and other macromolecules. The greener and more sustainable concepts used in analytical approaches for the quantification statins are also highlighted with current advancements.

The development and commercialization of bio-based and biodegradable polyhydroxyalkanoates (PHAs) biopolymers could be crucial for the transition toward a sustainable circular economy. However, despite potential traditional and novel applications in the packaging, textiles, agriculture, automotive, electronics, and biomedical industries, the commercialization of PHAs is limited by their current market competitiveness. This review provides the first critical assessment of the current pure culture pilot-scale PHA literature, which could be crucial in translating promising laboratory-scale developments into industrial-scale commercial PHA production. It will also complement reviews of mixed microbial cultures currently dominating pilot-scale PHA literature. Pure culture fermentations could provide advantages, such as ease of characterizing microbial producers' behavior, higher PHA productivities, and better alignment with existing PHA commercialization and industrial biotechnology approaches. Key aspects, including producer organisms, fermentation volumes and schemes, control schemes, optimization, and properties of the polymers produced, are discussed in-depth, to elucidate important trends, achievements, and knowledge gaps. Furthermore, specific ways for future pilot-scale studies to help address current PHA commercialization challenges are also identified. The insights, and recommendations provided will be extremely beneficial for the future development of PHA production, at both pilot and commercial scales, whilst also being beneficial to the production of other microbial polymers and industrial biotechnology as a whole.

Astaxanthin (AXT), a natural carotenoid, has strong antioxidant and anti-ageing effects and can reduce ultraviolet light-induced damage to cells and DNA, stimulate the immune system, and improve cardiovascular disease prognosis. Despite its wide applications in the: nutraceutical, cosmetic, aquaculture, and pharmaceutical industries, AXT industrial production and application are hindered by natural source scarcity, low production efficiency, and high requirements. This review compares the qualitative differences of AXT derived from different natural sources, evaluates the upstream procedures for AXT expression in different chassis organisms, and investigates synthetic biology- and cell factory-based strategies for the industrial production of natural AXT. Synthetic biology is a promising novel strategy for reprogramming plants or microorganisms to produce AXT. Additionally, genetic engineering using cell factories extends beyond terrestrial applications, as it may contribute to the long-term sustainability of human health during space exploration and migration endeavors. This review provides a theoretical basis for the efficient and accurate genetic engineering of AXT from the microalga Haematococcuspluvialis, providing a valuable reference for future research on the biomanufacturing of AXT and other biological metabolites.

CRISPR-based diagnostics (CRISPR/Dx) have revolutionized the field of molecular diagnostics. It enables home self-test, field-deployable, and point-of-care testing (POCT). Despite the great potential of CRISPR/Dx in diagnoses of biologically complex diseases, preamplification of the template often is required for the sensitive detection of low-abundance nucleic acids. Various amplification-free CRISPR/Dx systems were recently developed to enhance signal detection at sufficient sensitivity. Broadly, these amplification-free CRISPR/Dx systems are classified into five groups depending on the signal enhancement strategies employed: CRISPR/Cas12a and/or CRISPR/Cas13a are integrated with: (1) other catalytic enzymes (Cas14a, Csm6, Argonaute, duplex-specific nuclease, nanozyme, or T7 exonuclease), (2) rational-designed oligonucleotides (multivalent aptamer, tetrahedral DNA framework, RNA G-quadruplexes, DNA roller machine, switchable-caged guide RNA, hybrid locked RNA/DNA probe, hybridized cascade probe, or "U" rich stem-loop RNA), (3) nanomaterials (nanophotonic structure, gold nanoparticle, micromotor, or microbeads), (4) electrochemical and piezoelectric plate biosensors (SERS nanoprobes, graphene field-effect transistor, redox probe, or primer exchange reaction), or (5) cutting-edge detection technology platforms (digital bioanalysis, droplet microfluidic, smartphone camera, or single nanoparticle counting). Herein, we critically discuss the advances, pitfalls and future perspectives for these amplification-free CRISPR/Dx systems in nucleic acids detection. The continued refinement of these CRISPR/Dx systems will pave the road for rapid, cost-effective, ultrasensitive, and ultraspecific on-site detection without resorting to target amplification, with the ultimate goal of establishing CRISPR/Dx as the paragon of diagnostics.