Effects of palygorskite on steroid-transformation in Mycobacterium neoaurum

The low availability of hydrophobic substrates limited the bioproduction of steroid medications. As palygorskite (Pal) has excellent adsorption and dispersion capacity, Pal and modified Pal were incubated with Mycobacterium neoaurum TCCC 11979 (MNR) to investigate their effects on phytosterols (PS) biotransformation. The production of the steroid medicine intermediate androst-4-ene-3, 17-dione (AD) was remarkably improved with Pal or modified Pal as a carrier in PS biotransformation. Entropy and gas chromatography analyses confirmed that Pal samples increased the dispersion and adsorption of PS. Meanwhile, the cell permeability of MNR by nucleic acid improved. Among Pal samples, KH550 modified Pal showed superior properties, which results in the good dispersion of substrate and effectively improves the cell permeability without affecting cell growth (confirmed by TEM). Therefore, Pal, particularly KH550 modified Pal, can be used as a carrier in AD production by MNR. The data obtained will expand the application of Pal in the pharmaceutical industry and improve our understanding of the mechanism underlying the effect of Pal on the bioconversion of hydrophobic compounds.