Ceramide, a fundamental bioactive molecule found ubiquitously in eukaryotic organisms, exerts profound regulatory effect on cellular physiology, encompassing critical roles in signaling cascades, cellular proliferation, differentiation, and apoptosis, as well as immunomodulation. In dermatology, ceramides play an indispensable role as constituents of the stratum corneum, the outermost layer of the skin, where they are crucial for maintaining the integrity of the epidermal barrier, regulating moisture retention, combating oxidative stress linked to aging, and exhibiting notable antimicrobial and anti-inflammatory properties. The multifaceted biological functions of ceramides underscore their extensive applications in various industries, including cosmetics, biomedicine, functional food, and animal nutrition, highlighting their significant market potential and therapeutic value. The chemical synthesis of ceramides poses substantial challenges due to the intricate stereochemistry involved, necessitating precise control over synthetic pathways. As a result, current commercial sources predominantly rely on semi-synthetic methods that integrate traditional natural extraction techniques with biochemical transformations of sphingolipid precursors to achieve targeted ceramide structures. Recent advancements in synthetic biology have explored microbial systems for the production of sphingolipids, including ceramides, offering promising avenues for scalable and sustainable synthesis. However, optimizing de novo synthesis pathways and their efficiency in microbial cell factories remains a primary research focus. Strategies aimed at enhancing ceramide yield and purity through metabolic engineering and pathway optimization are pivotal for advancing industrial applications. This paper provides a systematic review of the physiological effectiveness and function of ceramides, encompassing their physiological roles and various applications. It begins with an overview of ceramide extraction methods, including both natural extraction techniques and chemical synthesis approaches for ceramides and their precursor compounds. Subsequently, the review addresses the sphingolipid synthesis pathways and their associated key enzymes, detailing strategies for pathway regulation and optimization, as well as the aspects of product transport, storage, and secretion. Additionally, it explores the identification and expression of key enzymes. The paper concludes by examining future directions in the field, such as addressing aggregation toxicity in ceramide synthesis, enhancing transport and secretion mechanisms, advancing digital modifications of catalytic elements, and expanding gene regulatory target exploration. By synthesizing current knowledge and highlighting avenues for innovation, this review aims to catalyze further research effort toward achieving efficient ceramide production. Ultimately, optimizing ceramide synthesis has the potential to unlock its full potential in various sectors, contributing to its advancement in skincare, therapeutics, and functional materials. The integration of microbial systems is particularly promising for expanding production capabilities while addressing sustainability concerns in ceramide manufacturing. Continued advancements in synthetic biology and biotechnology are expected to revolutionize the landscape of ceramide applications, paving the way for enhanced therapeutic interventions and novel industrial applications in the future.
