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.

Keywords: Mycobacterium; androstenedione; biosynthesis; pharmaceutical; phytosterol; steroid.

Figure 1

Biochemical pathway of androstenedione (AD) production from phytosterol, obtained from vegetable oils—mainly β-sitosterol. Dashed arrows indicate multiple enzymatic steps. HsD: 3β-hydroxysteroid dehydrogenase. The red dashed borders indicate the obstacles to AD production: the substrate’s low solubility and steroidal nucleus degradation. Green arrows indicate chemical reactions or extraction procedures [1,2,3,6].

Figure 2

Numbers of publications related to androstenedione (AD) production from phytosterols over the years (2000 to 2021).

Figure 3

Scientific articles that report the biosynthesis of androstenedione (AD) from phytosterols between 2000 and 2021, shown by country.

Figure 4

Publications about the androstenedione (AD) biosynthesis from phytosterols by different institutions between 2000 and 2021.

Figure 5

Different categories identified in the set of manuscripts involving androstenedione (AD) production from phytosterols, as found in the systematic search (meso analysis).

Figure 6

Different groups identified in the set of manuscripts, categorized as “microorganism” (microanalysis), for microbial androstenedione production from phytosterols.

Figure 7

Different groups identified in the set of manuscripts categorized as “process improvement” (microanalysis) for microbial androstenedione production from phytosterols.

Figure 8

Patents that report the biotransformation or biosynthesis of androstenedione (AD) between 1976 and March 2021.

Figure 9

Patent-holding institutions and patent applications for androstenedione production between 1976 and March 2021. * Filled by Noh, Seung-Kwon; Kim, Myung-Kuk; Yoon, Won-Tae; Park, Kyung-Moon; Park, Sang-Ok. ** Partnership between Emory University, Hauptman–Woodward Medical Research Institute, and the Research Foundation for the State University of New York.