## 1 Introduction  
Isoprenoids, a family of natural molecules with high chemical diversity, with over 80,000 known isoprenoids [1], are involved in the synthesis of secondary metabolites, such as carotenoids and sterols, in microorganisms, demonstrating promising commercial prospects for industrial production [2, 3]. All isoprenoids are derived from a simple C5 structural unit: isoprenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) [4], which are synthesized from or modified by isoprenyl diphosphate syntheses (IPPSs or IDSs), also known as premytransferases (PTs) [5]. PTs are involved in the biosynthesis of isoprenoids and regulate the production of secondary metabolites. According to the characteristics of the carbon chain lengths of the biosynthetic products, isoprenyl diphosphate synthases (IPPSs) are classified as follows: short-chain isoprenyl diphosphate synthases (SCIPPSs, C10-C25), medium-chain isoprenyl diphosphate synthases (MCIPPSs, C30-C35) and long-chain isoprenyl diphosphate synthases (LCIPPSs, C40-C50) [6], all of which are classified as trans types, according to the stereochemistry of the double bonds from IPP condensation [7]. By contrast, the product of cis-polypentenyl diphosphate synthase is polyisoprenoid (>C50), which catalyzes the synthesis of a double bond with an all-cis stereoisomeric configuration [8]. Farnesyl pyrophosphate synthase (known variously as FPPS, FPS, FDPS, FDS and EC 2.5.1.10), key enzyme in the metabolic pathway of isoprenoids, belong to the trans-SCIPPS family and catalyze the sequential irreversible 1'-4 condensation of DMAPP with IPPs to synthesize the finial product (2E,6E)-farnesyl diphosphate (FPP, C15). FPPS lead to an electron-deficient substrate carbon atom due to the loss of the diphosphate group and attack of the double-bonded electron-rich carbon atom on the IPP molecule [9]. In 1975, [PERSON] et al. [10] purified a homologous prenyltransferase from _Saccharomyces cerevisiae_, and in 1994 the first X-ray structure of the IPPSs was solved [11]. These results provided a basis to model homologous IPPs found in different species [12]. FPPSs are IPPSs that function as soluble homodimers, with each subunit weighing 32-44 kDa, and exist as single copies in the cytoplasm of microorganisms [13]. The FPPS catalyzing all-trans stereoisomerism consists mainly of \(\alpha\)-helices [11], which form a large reaction cavity in the middle of the protein and contain two aspartic acid-rich motifs, designated as the First Asp-Rich Motif (FARM) and the Second Asp-Rich Motif (SARM). These two motifs are typical IPPS active site domains and binding sites for the diphosphate moieties of IPPs and allylic substrates [14]. Previous studies have suggested that the fifth amino acid upstream of FARM is key for FPPS enzymatic activity [15]. _Sporoblomyces pararoseus_: NGR is unconventional and can yield high levels of carotenoids [16]. Carotenoids are lipid-soluble isoperneids with antioxidant activity and are precursors of vitamin A synthesis. Carotenoids are used therapeutically to improve immunity and prevent cancer and many chronic diseases and have great commercial value in cosmetics, as food additives and in the animal feed industries [17; 18]. In addition to carotenoids, the functional diversity of terpenoids enables them to play different roles in nature, such as hormones (gibberellins), photosynthetic pigments (phytol and carotenoids) and electronic carriers (ubiquane and plastid quinone), as well as toxins, insect repellents, etc. [19]. FPPSs are located upstream of the carotenoid biosynthesis pathway. They are responsible for the synthesis of C15 FPP, which is condensed with a molecule of IPP to form C20 GGPP, and via head-to-head condensation of two GGPPs forms the pigment synthesis intermediate C40 phytoene [20]. Changes in FPPS activity affect the flux of FPP to downstream metabolites, which means that the enzyme plays a vital role in regulating downstream metabolites [21; 22; 23].