Biotransformation of Phytosterols into Androstenedione—A Technological Prospecting Study

Abstract

Androstenedione (AD) is a key intermediate in the body’s steroid metabolism, used as a precursor for several steroid substances, such as testosterone, estradiol, ethinyl estradiol, testolactone, progesterone, cortisone, cortisol, prednisone, and prednisolone. The world market for AD and ADD (androstadienedione) exceeds 1000 tons per year, which stimulates the pharmaceutical industry’s search for newer and cheaper raw materials to produce steroidal compounds. In light of this interest, we aimed to investigate the progress of AD biosynthesis from phytosterols by prospecting scientific articles (Scopus, Web of Science, and Google Scholar databases) and patents (USPTO database). A wide variety of articles and patents involving AD and phytosterol were found in the last few decades, resulting in 108 relevant articles (from January 2000 to December 2021) and 23 patents of interest (from January 1976 to December 2021). The separation of these documents into macro, meso, and micro categories revealed that most studies (articles) are performed in China (54.8%) and in universities (76%), while patents are mostly granted to United States companies. It also highlights the fact that AD production studies are focused on “process improvement” techniques and on possible modifications of the “microorganism” involved in biosynthesis (64 and 62 documents, respectively). The most-reported “process improvement” technique is “chemical addition” (40%), which means that the addition of solvents, surfactants, cofactors, inducers, ionic liquids, etc., can significantly increase AD production. Microbial genetic modifications stand out in the “microorganism” category because this strategy improves AD yield considerably. These documents also revealed the main aspects of AD and ADD biosynthesis: Mycolicibacterium sp. (basonym: Mycobacterium sp.) (40%) and Mycolicibacterium neoaurum (known previously as Mycobacterium neoaurum) (32%) are the most recurrent species studied. Microbial incubation temperatures can vary from 29 °C to 37 °C; incubation can last from 72 h to 14 days; the mixture is agitated at 140 to 220 rpm; vegetable oils, mainly soybean, can be used as the source of a mixture of phytosterols. In general, the results obtained in the present technological prospecting study are fundamental to mapping the possibilities of AD biosynthesis process optimization, as well as to identifying emerging technologies and methodologies in this scenario.

New Insights into the Modification of the Non-Core Metabolic Pathway of Steroids in Mycolicibacterium and the Application of Fermentation Biotechnology in C-19 Steroid Production

“…In recent reviews, the background of AD-producing strains, types of substrates and treatment methods, yield, and other information have been outlined in detail [ 1 , 6 ]. In order to show more clearly the effects of different cofactor regulation strategies and transformation system production technology on AD production, the production yield and productivity of MNR and recombinant strains constructed based on different cofactor regulation strategies were compared ( Table 2 ).…”

“…C-19 steroids, especially AD, are the main raw materials for steroid hormone drugs. The global market for AD and ADD exceeds 1000 tons per year, and it is estimated that the global AD market will reach USD 210 million by 2025 [ 6 ]. Promoting the green, efficient, and low-cost production of C-19 steroids, such as AD, has become an important strategic demand for the global steroid pharmaceutical industry to achieve green, efficient production and sustainable development.…”

“…AD can also be converted to ADD in one step by 3-ketosteroid-∆1-dehydrogenase (KstD), which is a precursor for estrogens and glucocorticoids [ 5 ]. Thus, almost all steroid drugs can be synthesized from AD ( Figure 1 ) [ 6 ]. The establishment of a technology system for the microbial synthesis of AD with phytosterol as a substrate has now become the main production method of hormone steroid drugs [ 1 ].…”

Modular Coculture to Reduce Substrate Competition and Off-Target Intermediates in Androstenedione Biosynthesis

“…4AD is a highly valuable steroid precursor commonly used to produce a broad spectrum of therapeutically important hormones, such as testosterone and estradiol. − Recently, 4AD synthesis via microbial sterol biotransformation has made considerable progress at the industrial scale. − However, the starting substrates (sterols) need to be obtained from natural resources, and the low water solubility of sterols reduces their bioavailability during steroid production . In addition to classical biotransformation approaches, de novo steroid synthesis from simple carbon sources can be employed to obtain steroidal compounds in an environmentally friendly process. − However, to the best of our knowledge, no studies regarding the microbial de novo synthesis of 4AD have been reported to date.…”

“…19−21 However, the starting substrates (sterols) need to be obtained from natural resources, and the low water solubility of sterols reduces their bioavailability during steroid production. 18 In addition to classical biotransformation approaches, de novo steroid synthesis from simple carbon sources can be employed to obtain steroidal compounds in an environmentally friendly process. 22−25 However, to the best of our knowledge, no studies regarding the microbial de novo synthesis of 4AD have been reported to date.…”