title: [Hydroxylation of 16alpha, 17alpha-epoxy-4-pregenene-3, 20-dione by Absidia coerulea with pseudo-crystallo feed].
abstract: The 11-hydroxylation of 16alpha,17alpha-epoxy-4-pregenene-3,20-dione as a useful intermediate for the preparation of hormones can be achieved by the mycelium of Absidia coerulea at higher conversion rate than using other strains. In this paper 16alpha,17alpha-epoxy-4-pregenene-3,20-dione mixed with a little water, beta-cyclodextrin, Tween-80 was introduced into the fermentation broth after ultrasonication to increase pseudo-water-solubility of the hydrophobic substrate. This pseudo-crystallo feed could avoid the toxicity of organic solvents and was more available for the microbial transformation. The multi layer feed-forward neural network was used to setup a model which indicated the relationship between medium and feed components and the conversion rate. Particle swarm optimization (PSO), which was a stochastic global optimization algorithm and of which the convergence speed was high, was applied to obtain the optimal concentration of the medium and feed components. At optimum conditions with the pseudo-crystallo feed, the conversion rate of 16alpha,17alpha-epoxy-4-pregenene-3,20-dione at an initial concentration of 10 g/L was 87.5% in shaking flasks. The conversion rate of the substrate was up to 86.6% at higher concentration of 20 g/L feed in a 3.7 L fermentor.
authors.affiliation: Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Guan
authors.forename: Hai-Qing
authors.initials: HQ
authors.lastname: Wang
authors.forename: Shan-Jing
authors.initials: SJ
authors.lastname: Yao
mesh_terms: D020095:Absidia / Q000378:metabolism*; D005285:Fermentation; D006900:Hydroxylation; D011282:Pregnenediones / Q000378:metabolism*
chemical_list: D011282:Pregnenediones