Preparation, Characterization, and Biotransformation of the Inclusion Complex of Phytosterols and Hydroxypropyl-β- cyclodextrin by Mycobacterium neoaurum

Abstract

The inclusion complex of hydroxypropyl-β-cyclodextrin (HBβCD) and phytosterols (PSs) was prepared and characterized by thermogravimetric analysis (TGA) and infrared (IR) spectroscopy. Biotransformation of the inclusion complex of phytosterols and hydroxypropylβ-cyclodextrin (PSs-HBβCD) by Mycobacterium neoaurum to 1,4-androstadiene-3,17-dione and 4-androstene-3,17-dione [AD(D)] was studied. The TGA and IR results indicated that the thermal stability of PSs was improved in the complex with HBβCD. Biotransformation improved the solubility of PSs in the aqueous medium a lot because the AD(D) production was increased remarkably compared with the control, but growth of the bacteria was inhibited in the presence of HBβCD. The optimal inclusion ratio, ultrasonic treating time, dosage, and time of addition of PSs-HBβCD complexe were found to be 2:1, 10 min, 1.5 g/30 ml medium, and 48 h after incubation, respectively. This inclusion technique not only increased the availability of the substrates for the microorganisms, but also the capability of these microorganisms to produce AD(D) from PSs.

Effects of different carbon sources on growth, membrane permeability, β-sitosterol consumption, androstadienedione and androstenedione production by Mycobacterium neoaurum

“…The size of the world market for AD(D) compounds exceeds, 1000 tons per year (Schmid 2001). Biotransformation with microorganisms such as Mycobacterium neoaurum was regarded the most promising strain to transform phytosterols (including β-sitosterol, campesterol, brassicasterol, stigmasterol, etc) into AD(D) that performed side-chain cleavage of the substrate molecules (Rodina et al 2008; Wang and Yu 2011).…”