Advances in engineering the production of the natural red pigment lycopene: A systematic review from a biotechnology perspective

Recent advances in lycopene and germacrene a biosynthesis and their role as antineoplastic drugs

Sesquiterpenes and tetraterpenes are classes of plant-derived natural products with antineoplastic effects. While plant extraction of the sesquiterpene, germacrene A, and the tetraterpene, lycopene suffers supply chain deficits and poor yields, chemical synthesis has difficulties in separating stereoisomers. This review highlights cutting-edge developments in producing germacrene A and lycopene from microbial cell factories. We then summarize the antineoplastic properties of β-elemene (a thermal product from germacrene A), sesquiterpene lactones (metabolic products from germacrene A), and lycopene. We also elaborate on strategies to optimize microbial-based germacrene A and lycopene production.

Expanding the CRISPR Toolbox for Engineering Lycopene Biosynthesis in Corynebacterium glutamicum

Lycopene represents one of the central compounds in the carotenoid pathway and it exhibits a potent antioxidant ability with wide potential applications in medicine, food, and cosmetics. The microbial production of lycopene has received increasing concern in recent years. Corynebacterium glutamicum (C. glutamicum) is considered to be a safe and beneficial industrial production platform, naturally endowed with the ability to produce lycopene. However, the scarcity of efficient genetic tools and the challenge of identifying crucial metabolic genes impede further research on C. glutamicum for achieving high-yield lycopene production. To address these challenges, a novel genetic editing toolkit, CRISPR/MAD7 system, was established and developed. By optimizing the promoter, ORI and PAM sequences, the CRISPR/MAD7 system facilitated highly efficient gene deletion and exhibited a broad spectrum of PAM sites. Notably, 25 kb of DNA from the genome was successfully deleted. In addition, the CRISPR/MAD7 system was effectively utilized in the metabolic engineering of C. glutamicum, allowing for the simultaneous knockout of crtEb and crtR genes in one step to enhance the accumulation of lycopene by blocking the branching pathway. Through screening crucial genes such as crtE, crtB, crtI, idsA, idi, and cg0722, an optimal carotenogenic gene combination was obtained. Particularly, cg0722, a membrane protein gene, was found to play a vital role in lycopene production. Therefore, the CBIEbR strain was obtained by overexpressing cg0722, crtB, and crtI while strategically blocking the by-products of the lycopene pathway. As a result, the final engineered strain produced lycopene at 405.02 mg/L (9.52 mg/g dry cell weight, DCW) in fed-batch fermentation, representing the highest reported lycopene yield in C. glutamicum to date. In this study, a powerful and precise genetic tool was used to engineer C. glutamicum for lycopene production. Through the modifications between the host cell and the carotenogenic pathway, the lycopene yield was stepwise improved by 102-fold as compared to the starting strain. This study highlights the usefulness of the CRISPR/MAD7 toolbox, demonstrating its practical applications in the metabolic engineering of industrially robust C. glutamicum.

Construction and Regulation of the Abscisic Acid Biosynthesis Pathway in Yarrowia lipolytica

Abscisic acid (ABA) is an important plant hormone with a variety of physiological functions such as regulating plant growth and helping plants to resist an adverse growth environment. However, at present, the ABA yield of heterologous biosynthesis by metabolic engineering is still low for industrial production. Therefore, five Botrytis cinerea genes (bcaba1, bcaba2, bcaba3, bcaba4, and bccpr1) related to ABA biosynthesis were expressed in Yarrowia lipolytica PO1h; its ABA production was 24.33 mg/L. By increasing the copy number of IDI and ERG12S, ERG20YMT, and bcaba3, bcaba1 genes, the yield of ABA was increased to 54.51 mg/L. By locating HMG-CoA reductase and HMG-CoA synthase in mitochondria, acetyl-CoA in mitochondria was converted into mevalonate; this increased the ABA yield to 102.12 mg/L. Finally, in the fed-batch fermentation process with the addition of dodecane, the ABA yield was up to 1212.57 mg/L, which is the highest yield of heterologous production of ABA by metabolic engineering.

Therapeutic Effect of Natural Products and Dietary Supplements on Aflatoxin-Induced Nephropathy

Aflatoxins are harmful natural contaminants found in foods and are known to be hepatotoxic. However, recent studies have linked chronic consumption of aflatoxins to nephrotoxicity in both animals and humans. Here, we conducted a systematic review of active compounds, crude extracts, herbal formulations, and probiotics against aflatoxin-induced renal dysfunction, highlighting their mechanisms of action in both in vitro and in vivo studies. The natural products and dietary supplements discussed in this study alleviated aflatoxin-induced renal oxidative stress, inflammation, tissue damage, and markers of renal function, mostly in animal models. Therefore, the information provided in this review may improve the management of kidney disease associated with aflatoxin exposure and potentially aid in animal feed supplementation. However, future research is warranted to translate the outcomes of this study into clinical use in kidney patients.

Recent Advances on Key Enzymes of Microbial Origin in the Lycopene Biosynthesis Pathway

Lycopene is a common carotenoid found mainly in ripe red fruits and vegetables that is widely used in the food industry due to its characteristic color and health benefits. Microbial synthesis of lycopene is gradually replacing the traditional methods of plant extraction and chemical synthesis as a more economical and productive manufacturing strategy. The biosynthesis of lycopene is a typical multienzyme cascade reaction, and it is important to understand the characteristics of each key enzyme involved and how they are regulated. In this paper, the catalytic characteristics of the key enzymes involved in the lycopene biosynthesis pathway and related studies are first discussed in detail. Then, the strategies applied to the key enzymes of lycopene synthesis, including fusion proteins, enzyme screening, combinatorial engineering, CRISPR/Cas9-based gene editing, DNA assembly, and scaffolding technologies are purposefully illustrated and compared in terms of both traditional and emerging multienzyme regulatory strategies. Finally, future developments and regulatory options for multienzyme synthesis of lycopene and similar secondary metabolites are also discussed.

Optimization of antioxidant and lycopene extraction from tomato pomace using Hansen solubility parameters and its application in chicken meat preservation

Tomato pomace, composed of peels and seeds, is often discarded or used as animal feed. However, it contains valuable phytochemicals, including lycopene. Lycopene, a natural pigment, is an antioxidant known for reducing the risk of chronic diseases like cardiovascular ailments and cancer. In this study, we aimed to study the possibility of valorizing tomato pomace by quantifying phenolic compounds, evaluating the antioxidant activity of their extracts, as well as extracting and quantifying lycopene, and studying the effect of tomato peel extract on the oxidative stability of chicken patties during storage. The effectiveness of different solvent mixtures for the extraction of lycopene was evaluated using Hansen solubility parameters (HSPs). The obtained results showed that the best solvent mixture was hexane/acetone (50/50) with a Hansen theoretical distance of 7.2, indicating its favorable solvation power. It also achieved a notable extraction yield of 3.12% and the highest lycopene yield of 20.05 mg/100 g. This combination demonstrated the highest values in terms of total phenolic (24.06 mg equivalent gallic acid/100 g dry matter) and flavonoid content (30.55 mg equivalent catechin/100 g dry matter), indicating a significant presence of these compounds. However, its 1,1-diphenyl-2-picrylhydrazyl (13.51 µg/mL) and ABTS, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, (8.52 µg/mL) IC50 values were comparatively lower than the other mixes. The use of this fraction as a food additive and antioxidant showed significant competitiveness with the conventional preservative, 2,6-di-tert-butyl-4-methylphenol. Tomato extract can be considered a potential natural preservative in food preparations due to its high lycopene content. PRACTICAL APPLICATION: This research provides valuable insights into optimizing the extraction of antioxidants from tomato pomace, using HSPs. The findings have the potential to benefit the food industry by developing improved methods for preserving chicken meat through the application of these optimized antioxidant extracts. By enhancing the preservation process, this study may contribute to extending the shelf life and maintaining the quality of chicken meat, leading to reduced food waste and improved consumer satisfaction.

The Importance of Antioxidant Activity for the Health-Promoting Effect of Lycopene

Lycopene is a compound of colored origin that shows strong antioxidant activity. The positive effect of lycopene is the result of its pleiotropic effect. The ability to neutralize free radicals via lycopene is one of the foundations of its pro-health effect, including the ability to inhibit the development of many civilization diseases. Therefore, this study focuses on the importance of the antioxidant effect of lycopene in inhibiting the development of diseases such as cardiovascular diseases, diseases within the nervous system, diabetes, liver diseases, and ulcerative colitis. According to the research mentioned, lycopene supplementation has significant promise for the treatment of illnesses marked by chronic inflammation and oxidative stress. However, the majority of the supporting data for lycopene's health benefits comes from experimental research, whereas the evidence from clinical studies is both scarcer and less certain of any health benefits. Research on humans is still required to establish its effectiveness.

Increased Cordycepin Production in Yarrowia lipolytica Using Combinatorial Metabolic Engineering Strategies

As the first nucleoside antibiotic discovered in fungi, cordycepin, with its various biological activities, has wide applications. At present, cordycepin is mainly obtained from the natural fruiting bodies of Cordyceps militaris. However, due to long production periods, low yields, and low extraction efficiency, harvesting cordycepin from natural C. militaris is not ideal, making it difficult to meet market demands. In this study, an engineered Yarrowia lipolytica YlCor-18 strain, constructed by combining metabolic engineering strategies, achieved efficient de novo cordycepin production from glucose. First, the cordycepin biosynthetic pathway derived from C. militaris was introduced into Y. lipolytica. Furthermore, metabolic engineering strategies including promoter, protein, adenosine triphosphate, and precursor engineering were combined to enhance the synthetic ability of engineered strains of cordycepin. Fermentation conditions were also optimized, after which, the production titer and yields of cordycepin in the engineered strain YlCor-18 under fed-batch fermentation were improved to 4362.54 mg/L and 213.85 mg/g, respectively, after 168 h. This study demonstrates the potential of Y. lipolytica as a cell factory for cordycepin synthesis, which will serve as the model for the green biomanufacturing of other nucleoside antibiotics using artificial cell factories.

Research Progress on Lycopene in Swine and Poultry Nutrition: An Update

Oxidative stress and in-feed antibiotics restrictions have accelerated the development of natural, green, safe feed additives for swine and poultry diets. Lycopene has the greatest antioxidant potential among the carotenoids, due to its specific chemical structure. In the past decade, increasing attention has been paid to lycopene as a functional additive for swine and poultry feed. In this review, we systematically summarized the latest research progress on lycopene in swine and poultry nutrition during the past ten years (2013-2022). We primarily focused on the effects of lycopene on productivity, meat and egg quality, antioxidant function, immune function, lipid metabolism, and intestinal physiological functions. The output of this review highlights the crucial foundation of lycopene as a functional feed supplement for animal nutrition.

A mechanistic updated overview on lycopene as potential anticancer agent

The potent relation between lycopene intake and reduced incidence of a variety of cancers has an increasing interest. This comprehensive review aims to highlight the in vivo and in vitro research evaluating the anticancer mechanisms of lycopene by underlining the experiment conditions. In addition to these, the general characterization of lycopene has been explained. A collection of relevant scientific pharmacological articles from the following databases PubMed/MedLine, Web of Science, Scopus, TRIP database, and Google Scholar on the mechanisms of anticancer molecular action and cellular effects of lycopene in various types of tumors was performed. The anticancer potential of lycopene has been described by various in vitro cells, animal studies, and some clinical trials. It has been revealed that the anticancer potential of lycopene is mainly due to its powerful singlet-oxygen quencher characteristics, simulation of detoxifying/antioxidant enzymes production, initiation of apoptosis, inhibition of cell proliferation and cell cycle progression as well as modulations of gap junctional communication, the growth factors, and signal transduction pathways. It has been highlighted that the anticancer properties of lycopene are primarily linked to factors including; dose, presence of drug delivery systems, type of cancer, tumor size, and treatment time.

Microbes of traditional fermentation processes as synthetic biology chassis to tackle future food challenges

Microbial diversity is magnificent and essential to almost all life on Earth. Microbes are an essential part of every human, allowing us to utilize otherwise inaccessible resources. It is no surprise that humans started, initially unconsciously, domesticating microbes for food production: one may call this microbial domestication 1.0. Sourdough bread is just one of the miracles performed by microbial fermentation, allowing extraction of more nutrients from flour and at the same time creating a fluffy and delicious loaf. There are a broad range of products the production of which requires fermentation such as chocolate, cheese, coffee and vinegar. Eventually, with the rise of microscopy, humans became aware of microbial life. Today our knowledge and technological advances allow us to genetically engineer microbes - one may call this microbial domestication 2.0. Synthetic biology and microbial chassis adaptation allow us to tackle current and future food challenges. One of the most apparent challenges is the limited space on Earth available for agriculture and its major tolls on the environment through use of pesticides and the replacement of ecosystems with monocultures. Further challenges include transport and packaging, exacerbated by the 24/7 on-demand mentality of many customers. Synthetic biology already tackles multiple food challenges and will be able to tackle many future food challenges. In this perspective article, we highlight recent microbial synthetic biology research to address future food challenges. We further give a perspective on how synthetic biology tools may teach old microbes new tricks, and what standardized microbial domestication could look like.