Abstract:BackgroundCholesterol, the precursor of all steroid hormones, is the most abundant steroid in vertebrates and exhibits highly hydrophobic properties, rendering it a difficult substrate for aqueous microbial biotransformations. In the present study, we developed a Bacillus megaterium based whole-cell system that allows the side-chain cleavage of this sterol and investigated the underlying physiological basis of the biocatalysis.ResultsCYP11A1, the side-chain cleaving cytochrome P450, was recombinantly expressed… Show more
“…Its use in the pharmaceutical and food industries is preferred due to the ability of this bacterium to grow on a variety of carbon sources and simple media as well as due to its high protein production capacity and plasmid stability . Importantly, as shown by research results considering various P450 enzymes, the B. megaterium offers certain advantages, of being not only a source of new, uncharacterized P450s but also a very good host for P450s and/or their homologous or heterologous redox partners . Use of the whole‐cell expressed P450(s) in a biotransformation process allows for regeneration of the expensive NADPH cofactor that is necessary for P450 activity.…”
“…Its use in the pharmaceutical and food industries is preferred due to the ability of this bacterium to grow on a variety of carbon sources and simple media as well as due to its high protein production capacity and plasmid stability . Importantly, as shown by research results considering various P450 enzymes, the B. megaterium offers certain advantages, of being not only a source of new, uncharacterized P450s but also a very good host for P450s and/or their homologous or heterologous redox partners . Use of the whole‐cell expressed P450(s) in a biotransformation process allows for regeneration of the expensive NADPH cofactor that is necessary for P450 activity.…”
“…megaterium membrane, Quillaja saponin, with a final concentration of 0.2 %, was used. This surface‐active glycoside was previously demonstrated to strongly increase the cholesterol conversion rate of another P450‐based whole‐cell system in B. megaterium . Interestingly, the CYP109E1 whole‐cell system showed limited activity towards cholesterol, with a conversion ratio of about 20 %, yielding (13.6±2.4) mg L −1 of products after 48 h of reaction (Figure B).…”
Section: Figurementioning
confidence: 99%
“…The reasons for the observed low activity of CYP109E1 towards cholesterol in B. megaterium cells are not yet clear, but might be related to limited cholesterol accessibility for P450 during whole‐cell conversion. It was previously shown that cholesterol tends to accumulate in the poly(3‐hydroxybutyrate) (PHB) bodies in B. megaterium , whereas CYP109E1 is a cytosolic P450 located in the cytoplasm. Moreover, the strain encodes other P450s with unknown natural substrates, which might also bind cholesterol or consume electrons for other reactions.…”
In this study, the ability of CYP109E1 from Bacillus megaterium DSM319 to metabolize cholesterol was investigated. This steroid was identified as a new substrate to be converted by CYP109E1 with adrenodoxin and adrenodoxin reductase as redox partners in vitro. The biotransformation was successfully reproduced in vivo by using Bacillus megaterium cells that overexpressed CYP109E1. To enhance the production of cholesterol derivatives, an Escherichia coli based whole‐cell system that harbored CYP109E1 was established. This novel system showed a 3.3‐fold higher activity than that of the B. megaterium system, yielding about 45 mg L−1 of these products. Finally, the reaction products were isolated and identified to be the highly important cholesterol derivatives 24(S)‐ and 25‐hydroxycholesterol.
“…The steroid pharmaceuticals are of great importance for their role in the management of human fertility, osteoporosis, menopause and blood pressure regulation [2,3]. Commercially, steroid production represents one of the largest sectors of medical products manufactured by the pharmaceutical industry [4]. Production of AD and androstadienedione (ADD) exceeds 1000 tons per year in the world.…”
Androstenedione (AD) is a steroid intermediate valuable for the production of steroid medicaments. Microbial biotransformation of phytosterol to produce AD is a wellresearched area. However, low substrate solubility of phytosterol in aqueous media and nucleus degradation of AD to androstadienedione (ADD) or 9-hydroxy-AD are the major obstacles for AD production leading to detailed research for optimization of biotransformation process. In this review, microbial transformation of AD with respect to the existing methods of chemical or biochemical synthesis of AD are extensively discussed. This review examines the microbial biotransformation process and limitations for enhanced AD production. Factors affecting the effective biotransformation process to obtain AD are discussed and limitations are highlighted. The main content of this review focuses on the recent and futuristic biotechnological advances and strategies in techniques to enhance AD bioprocess.
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