The demand for personal care products has been increasing steadily. Consumers are now seeking for products that offer enhanced functionality, natural ingredients, and superior feeling experiences. Fragrances and flavors are key components in personal care formulations. Terpenes and their derivatives dominate natural fragrances due to their diverse structures and scents, widespread availability from plants and animals, stable function, and high safety profile. The terpene fragrance market is projected to grow at an annual growth rate of 6.4%, reaching $1.01 billion by 2028, indicating a high market revenue and promising future. Currently, the acquisition of natural terpene fragrances is constrained by the long growth cycle of plants, low terpene content, and high extraction cost. Thus, there is an urgent need for developing new technology, such as synthetic biology, to achieve large-scale production of diverse fragrance compounds at an environment-friendly manner. This review explores the application and development of synthetic biology in the sustainable production of terpene fragrances, highlighting how data-driven synthetic biology and biotechnological innovations empower terpene fragrance production. It also compares classical and alternative terpenoid biosynthesis pathways, elucidating their differences and advantages, which can offer comprehensive insights for chassis design toward terpenoid efficient biosynthesis. Additionally, this review explores recent advances in terpene synthase discovery and engineering as well as cell factory construction. Furthermore, we comprehensively summarizes challenges encountered in the construction of three major types of terpene fragrance cell factories: monoterpenes, sesquiterpenes, and nor-isoprenoids, and discusses metabolic engineering strategies that can be employed to address these issues, including enzyme optimization, pathway reconstruction, and cellular detoxification. At the end, we comment the current landscape of patents and industrial competition, offering insights into future challenges and opportunities, including the hurdles of biosynthesis technology, the discovery and design of new products, as well as the market regulation and safety concerns.

Flavonoids are natural ingredients commonly used in cosmetics, mainly for their antioxidant and anti-inflammatory effects, but they also present a variety of other biological activities such as antimicrobial, whitening, and anti-ultraviolet. Therefore, flavonoids have a huge application potential waiting to be explored. In this review, firstly, the numerous biological properties of flavonoids used in cosmetics, as well as examples of their applications in cosmetics are presented, with their biosynthetic pathways addressed. Then, recent advances in biosynthesis of typical flavonoids (e.g., phloretin, naringenin, apigenin, luteolin, chrysin, rutin, and anthocyanins) are reviewed and discussed, with a focus on the novel synthetic biology and metabolic engineering strategies to improve the productivity and yield of biosynthesized flavonoids, including the enhancement of precursor supply, characterization and modification of key enzymes, regulation of gene expression, and optimization of fermentation processes. With the continuous innovation of synthetic biology technology, there has been an increase in the efficiency of flavonoid biosynthesis and a significant reduction in production cost, which contributes substantially to the widespread use of flavonoids in cosmetics. However, the prevalence of poor solubility and low stability of flavonoids limits their applications in cosmetics. To address this issue, we outline the research process of two main strategies: nanocarrier technology and moiety modification. The application of these research results opens up new possibilities for the use of flavonoids in cosmetics. At the end, we discuss two major challenges in high-yield synthesis of complex flavonoids: the difficulty of key enzyme modification and the imbalance of metabolic flux. We also look forward to AI-assisted synthetic biology to address these challenges and drive the yield improvement and industrialization of flavonoid biosynthesis, providing biotechnological power for the development and innovation of the cosmetics industry.

The development of synthetic biology has witnessed rapid advancements, which have significantly promoted production innovations in multiple sectors. In the cosmetics industry, the production methods of amino acid derivatives, which are a kind of pivotal raw materials in cosmetics, are experiencing groundbreaking innovations. The traditional methods for the production of amino acid derivatives have the problem of high cost, and usually generate environmental risk. Besides, the production stabilities of the target products are often unsatisfactory. The application of synthetic biology technology in the design and engineering of microbial cell factories for the bioproduction of amino acid derivatives, can greatly enhance the production efficiency and reduce the production costs of the target products. This innovative approach not only enhances the development of green biomanufacturing, but also benefits the demand of market for natural, safe, and functional cosmetic ingredients. In this review, an overall introduction to the utilization of amino acid derivatives in cosmetics industry is first provided. Subsequently, the strategies for the construction of high-producing strains for the production of amino acid derivatives are comprehensively summarized, which are basically categorized into two groups: enzyme conversion and microbial fermentation. The application of enzyme engineering, rational metabolic engineering, and random screening in the construction of microbial cell factories for the production of amino acid derivatives are systematically introduced. Moreover, the current research advancements and trends in the biosynthesis of amino acid derivatives as cosmetic raw materials are outlined. With the support of the cutting-edge technologies such as artificial intelligence, synthetic biology will further promote the production innovation process, enabling efficient and eco-friendly biomanufacturing of a wider array of cosmetic raw materials. This ongoing evolution holds immense promise for the cosmetics industry, promising a future with sustainable and innovative products.

Hyaluronic acid (HA), a natural linear acidic polysaccharide composed of disaccharide units of D-glucuronic acid (D-GlcA) and N-acetylglucosamine (N-GlcNAc), has been widely used in the cosmetic and medical fields. HAs with different molecular weights exhibit distinct biophysical properties. While high molecular weight HAs have stronger viscoelasticity and resistance to degradation, low molecular weight HAs demonstrate enhanced biological functions. Significant progress has been made for the industrial production of HAs, with the shift from traditional extraction from animal tissues to microbial fermentation. However, the use of the natural HA-producing species Streptococcus zooepidemicus presents challenges, such as potential pathogenicity and difficulties in molecular modifications, which limit the study on the biosynthesis of HAs with varying molecular weights. Recently, the increasing demand for specific molecular weight HAs has driven the application of metabolic engineering and synthetic biology techniques for their biosynthesis and molecular weight regulation. By identifying the key factors involved in the processes, researchers have developed various strategies to optimize the synthesis of HAs and control their molecular weights. This article first analyzes the limiting factors in the synthesis of medium and high molecular weight HAs, focusing on the genetic regulation on the synthesis pathways of HA precursors and the weakening of competitive branches. Secondly, it discusses the impact of HA synthase, precursor supply, and fermentation conditions on the synthesis of ultra-high molecular weight HAs. Finally, it summarizes the preparation strategies for low molecular weight HAs, including physical and chemical methods, enzymatic methods, and microbial direct fermentation as well. The review summarizes the latest research progress regarding challenges faced in the biosynthesis and molecular weight regulation of HAs: specifically, the insufficient molecular weight of high molecular weight HAs, the weak synthesis capability of medium molecular weight HAs, and the poor controllability of low molecular weight HAs. It provides a systematic overview on enhancing the understanding of strategies for HA biosynthesis and molecular weight regulation, aiming to facilitate the efficient biosynthesis of HAs with controlled molecular weights.

Mycosporine-like amino acids (MAAs), a class of natural sunproof molecules, have attracted intensive attention because of their potent ultraviolet (UV) -absorbing capabilities and potential applications in the cosmetics industry. However, the complicated extraction process and low yield restrict their applications. To address challenges with the supply of MAAs, reconstructing the biosynthesis pathway for their production in microbial cells with synthetic biology techniques provides an effective strategy. This article systematically reviews current progress in the biosynthesis of MAAs, covering a range of critical aspects, including the analysis of structural diversity, which is essential for understanding the functional properties of different MAAs. Additionally, the article delves into the elucidation of biosynthetic pathways, providing insights into the biochemical steps and enzymes involved in the production of MAAs. Furthermore, this review explores the construction of chassis cells in the biosynthesis of MAAs, including the integration of heterologous genes and the optimization of metabolic pathways, highlighting the importance of selecting and engineering suitable microbial hosts to optimize MAAs biosynthesis. The review provides a forward-looking perspective on microbial synthesis of MAAs, with a focus on driving innovation in green and efficient biomanufacturing of these high-value compounds. Meanwhile, the article also discusses the current key challenges in MAAs biosynthesis research, including low precursor content, insufficient enzyme catalytic activity, and difficulties in accurate product identification, which collectively hinder the industrial development of MAAs. Breaking through these technical bottlenecks is expected to enable the development of sustainable and economically viable approaches for the large-scale production of MAAs. This review introduces the current status of research on MAAs synthesized by microbial cells from multiple perspectives and makes a prospective analysis of future development trends, aiming to provide a reference and guidance for research on microbial synthesis of MAAs. Biosynthesis technology shows promise in replacing traditional extraction methods, potentially revolutionizing the production mode of MAAs fundamentally. This innovative production approach will not only satisfy the growing demand for MAAs in the cosmetics industry, but will also significantly improve the accessibility and usage of MAAs in multiple fields.

Monoterpenoids constitute a significant subclass of terpenoids, known for their volatility and strong aromatic properties. These compounds are extensively employed across multiple sectors, including pharmaceuticals, foods, flavors, cosmetics, agriculture, and energy, due to their diverse pharmacological and biological activities. Currently, monoterpenoids are primarily sourced from plant extracts or chemical synthesis. However, low yield and high cost associated with plant extracts as well as low purity and high energy consumption with chemical synthesis cannot address the growing demand. As a result, the heterologous synthesis of monoterpenoids using microorganisms presents an alternative pathway that is efficient, sustainable, and eco-friendly. Yeasts show promise as hosts for monoterpenoid biosynthesis due to their fast growth, inherent mevalonate (MVA) pathway, and robust post-translational modification systems. Currently, the industrial production of the artemisinin precursor artemisinic acid and the sesquiterpene farnesene has been achieved using Saccharomyces cerevisiae. Advances in synthetic biology have enabled the construction of microbial cell factories for monoterpenoid synthesis. However, challenges remain in scaling up production due to limited precursor availability and monoterpene cytotoxicity. This review first introduces the foundational pathways of monoterpenoid biosynthesis in yeast, followed by discussion on engineering strategies and advancements in yeast-mediated monoterpenoid synthesis, which include enhancing the supply and utilization of acetyl coenzyme A and geranyl pyrophosphate (GPP), regulating and modifying key enzymes such as GPP synthase and monoterpene synthase, optimizing subcellular organelle localization and compartmentalization of MVA pathway genes and monoterpenoid synthases, and implementing exocytosis and tolerance engineering to mitigate monoterpene cytotoxicity. Future directions and strategies to overcome bottlenecks in microbial synthesis are explored to guide research in yeast synthesis of monoterpenoids.

With the rapid growth of consumption in cosmetics, demand for their raw materials is expanding correspondingly, which not only drive the efficacy and product competitiveness but are also crucial for ensuring safety. Synthetic biology, an emerging interdisciplinary field based on engineering principles, leverages gene editing, computer simulation, and bioengineering technologies to design, modify, and even resynthesize organisms through rational strategies. Saccharomyces cerevisiae, an important microbial platform, is increasingly used in the production of cosmetic raw materials. Constructing S. cerevisiae cell factories for the heterologous biosynthesis of cosmetic ingredients presents an eco-friendly and sustainable alternative to traditional plant extraction and chemical synthesis, addressing both environmental concern and resource limitation. In this article, we review the development of gene editing technology and its key role in constructing biosynthetic pathways for the production of cosmetic raw materials with S. cerevisiae. We also summarize the application of metabolic engineering strategies such as multi-copy gene integration, compartmentalization, transporter engineering, and multicellular system in the optimization of S. cerevisiae cell factories. Moreover, we present the latest progress in the biosynthesis of different cosmetic active ingredients with S. cerevisiae cell factories, such as terpenes, vitamins, polyphenols, proteins and amino acids. While the potential and advantages of using S. cerevisiae for large-scale production of cosmetic raw materials are significant, a series of challenges remain, including incomplete biosynthetic pathway analysis, low biosynthesis yield, and low yield with the separation and purification. Looking ahead, the integration of artificial intelligence, machine learning, and other advanced technologies is expected to establish more efficient gene editing tools for the optimization of yeast cell factories and the biosynthesis of cosmetic raw materials, providing technical support and practical guidance for the sustainable development of the cosmetics industry.

L-arginine is an alkaline amino acid that has been used as a neutralizer, moisturizer, and antioxidant in skin care products. In addition, L-arginine is also widely used in feed, medicine, and food industries. The wide range of applications for L-arginine has garnered significant attention for its robust production. L-arginine can be produced through protein hydrolysis and microbial fermentation. However, protein hydrolysis has drawbacks, including complicated operation, high purification cost, low recovery efficiency, and environmental pollution. In contrast, the microbial fermentation can use renewable and cheap feedstock. Besides, the process is performed under mild conditions, and thus is more environmentally friendly. At present, engineered microorganisms such as Corynebacterium glutamicum and Escherichia coli are major producers of L-arginine, and design and construction of microbial strains is the robust production of L-arginine through microbial fermentation. Random mutagenesis and screening strategies are used to develop L-arginine producing microbial strains, which are random with uncertainties, resulting in a low-efficiency for the breeding. With the development of synthetic biotechnology, development of L-arginine producing strains is empowered by the rational design of artificial synthetic pathways and regulatory machineries, taking advantages of advanced genome editing technologies. This paper reviews the progress in the studies of the synthetic pathways and regulatory mechanisms of L-arginine production that have been discovered in different microorganisms. Synthetic biology-guided metabolic engineering strategies for improving L-arginine production in C. glutamicum and E. coli are summarized. Besides, the application of the biosensor-based high-throughput screening strategy for selecting L-arginine producing strains is introduced. Finally, potential strategies to enhancing L-arginine production and the possibility of using new carbon resources such as non-food biomass and one-carbon feedstock for L-arginine production are discussed. It is envisioned that synthetic biology-guided strain engineering will further enhance the production of L-arginine, particularly using non-food feedstock in the near future.

Functional peptides are short chain peptides composed of 2 to 50 amino acids, and their biological activities are closely related to their amino acid sequences, chain length, and structural architectures. Functional peptides can play a regulatory role in a variety of physiological processes by specifically recognizing and binding to target molecules in vivo. Due to their rapid action, strong specificity, less side effect and toxicity, functional peptides have shown great application potentials in many fields such as biomedicine, food science and cosmetics. For example, in the field of biomedicine, functional peptides can be used as the basic material of antimicrobe, anticancer, immune regulation and other therapeutic factors. In the food industry, they are used as natural supplements to enhance nutritional value for health benefit. In the field of cosmetics, functional peptides are widely used for the anti-aging, moisturizing, and repairing of the skin. In this paper, we discuss the ways of obtaining functional peptides, mainly including protein hydrolysis, chemical synthesis, and biosynthesis (e.g., through microbial recombinant expression technology), and compare their advantages and disadvantages and respective application scenarios. In terms of strategies for mining functional peptides, we review the latest research progress including phage surface display, machine learning algorithm, molecular docking and artificial intelligence. These techniques show significant potentials in the screening and design of functional peptides. In recent years, the rapid development of synthetic biology and the wide applications of bioinformatics and artificial intelligence have provided new ideas and strategies for the discovery and optimization of functional peptides, making it possible to screen functional peptides through machine learning and high throughput. Looking forward to the future, the research of functional peptides will face new challenges and opportunities. Improving the synthesis process for high efficiency, improving the stability of functional peptides through structural modifications, and using computer-aided optimization and artificial intelligence to design multifunctional peptides will become important research directions. At the same time, strengthening the safety and efficacy assessment of functional peptides can further enhance the applications of functional peptides.