Improving the production of squalene-type triterpenoid 2,3;22,23-squalene dioxide by optimizing the expression of CYP505D13 in Saccharomyces cerevisiae

Multiplexed engineering of cytochrome P450 enzymes for promoting terpenoid synthesis in Saccharomyces cerevisiae cell factories: A review

Terpenoids, also known as isoprenoids, represent the largest and most structurally diverse family of natural products, and their biosynthesis is closely related to cytochrome P450 enzymes (P450s). Given the limitations of direct extraction from natural resources, such as low productivity and environmental concerns, heterologous expression of P450s in microbial cell factories has emerged as a promising, efficient, and sustainable strategy for terpenoid production. The yeast expression system is a preferred selection for terpenoid synthesis because of its inner membrane system, which is required for eukaryotic P450 expression, and the inherent mevalonate pathway providing precursors for terpenoid synthesis. In this review, we discuss the advanced strategies used to enhance the local enzyme concentration and catalytic properties of P450s in Saccharomyces cerevisiae, with a focus on recent developments in metabolic and protein engineering. Expression enhancement and subcellular compartmentalization are specifically employed to increase the local enzyme concentration, whereas cofactor, redox partner, and enzyme engineering are utilized to improve the catalytic efficiency and substrate specificity of P450s. Subsequently, we discuss the application of P450s for the pathway engineering of terpenoid synthesis and whole-cell biotransformation, which are profitable for the industrial application of P450s in S. cerevisiae chassis. Finally, we explore the potential of using computational and artificial intelligence technologies to rationally design and construct high-performance cell factories, which offer promising pathways for future terpenoid biosynthesis.

Biosynthesis of mushroom-derived type II ganoderic acids by engineered yeast

Type II ganoderic acids (GAs) produced by the traditional medicinal mushroom Ganoderma are a group of triterpenoids with superior biological activities. However, challenges in the genetic manipulation of the native producer, low level of accumulation in the farmed mushroom, the vulnerabilities of the farming-based supply chain, and the elusive biosynthetic pathway have hindered the efficient production of type II GAs. Here, we assemble the genome of type II GAs accumulating G. lucidum accession, screen cytochrome P450 enzymes (CYPs) identified from G. lucidum in baker's yeast, identify key missing CYPs involved in type II GAs biosynthesis, and investigate the catalytic reaction sequence of a promiscuous CYP. Then, we engineer baker's yeast for bioproduciton of GA-Y (3) and GA-Jb (4) and achieve their production at higher level than those from the farmed mushroom. Our findings facilitate the further deconvolution of the complex GA biosynthetic network and the development of microbial cell factories for producing GAs at commercial scale.

Biosynthetic pathways of triterpenoids and strategies to improve their Biosynthetic Efficiency

"Triterpenoids" can be considered natural products derived from the cyclization of squalene, yielding 3-deoxytriterpenes (hydrocarbons) or 3-hydroxytriterpenes. Triterpenoids are metabolites of these two classes of triterpenes, produced by the functionalization of their carbon skeleton. They can be categorized into different groups based on their structural formula/design. Triterpenoids are an important group of compounds that are widely used in the fields of pharmacology, food, and industrial biotechnology. However, inadequate synthetic methods and insufficient knowledge of the biosynthesis of triterpenoids, such as their structure, enzymatic activity, and the methods used to produce pure and active triterpenoids, are key problems that limit the production of these active metabolites. Here, we summarize the derivatives, pharmaceutical properties, and biosynthetic pathways of triterpenoids and review the enzymes involved in their biosynthetic pathway. Furthermore, we concluded the screening methods, identified the genes involved in the pathways, and highlighted the appropriate strategies used to enhance their biosynthetic production to facilitate the commercial process of triterpenoids through the synthetic biology method.