Abstract:

Ceramide, a fundamental bioactive molecule found ubiquitously in eukaryotic organisms, exerts profound regulatory effects on cellular physiology, encompassing critical roles in signaling cascades, cellular proliferation, differentiation, apoptosis, and 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 across 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 have explored microbial systems for the production of sphingolipids, including ceramides, offering promising avenues for scalable and sustainable synthesis. However, optimizing de novo synthesis 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 effects and functions 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 pathway and its associated key enzymes, detailing strategies for pathway regulation and optimization, as well as aspects of product transport, storage, and secretion. Additionally, it explores the identification and expression of key enzyme. 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 efforts toward achieving efficient ceramide production. Ultimately, optimizing ceramide synthesis has the potential to unlock its full potential across diverse sectors, contributing to advancements 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 years ahead.

Key words: ceramide, microbial cell factories, biosynthesis, sphingolipids, sphingosine alkali

摘要：

神经酰胺是一种存在于所有真核生物中的多功能生物活性物质，在细胞信号转导、细胞增殖、分化、凋亡和免疫调节中发挥着重要作用。神经酰胺天然存在于皮肤角质层中，起着支持肌肤屏障、保持水分、抗氧化衰老、抗菌抗炎等作用。因此，神经酰胺及其衍生物在化妆品、生物医药、功能食品等领域具有广阔的市场前景。神经酰胺构型存在多个立体中心，化学从头合成难度大，已知市售的天然或类神经酰胺化合物主要是通过传统天然提取法及生物化学相结合的半合成法获得。近年来，利用微生物合成神经酰胺等鞘脂类化合物已有报道，但从头合成效率还处于较低水平，如何实现细胞工厂高效生产神经酰胺具有重大意义。本文首先从神经酰胺的生理功能和应用出发，系统地综述了神经酰胺类物质的生理效应及功能；其次阐述了神经酰胺的天然提取方法、神经酰胺及其前体化合物的化学合成方法；接下来，从鞘脂合成途径及关键酶出发介绍，引出途径调控与优化、产物的运输储存与分泌、关键酶的挖掘与表达等改造策略；最后，从神经酰胺合成面临的聚集毒性、高效运输分泌、数字化改造催化元件、基因调控靶点的拓展等方面进行了展望。合成生物学和生物技术的持续进步有助于扩大微生物细胞工厂的生产能力，实现神经酰胺等鞘脂类化合物的可持续绿色生物制造。

关键词: 神经酰胺, 微生物细胞工厂, 生物合成, 鞘脂, 鞘氨醇碱