Improving Biotransformation Efficiency of by Enhancement of Cell Stress Tolerance and Enzyme Activity.

exhibits excellent Δ-dehydrogenation ability, but the acquisition of the desirable strain is limited due to lacking of comprehensive genetic manipulation. Herein, a promoter collection for fine-tuning gene expression was achieved. Next, the expression level was enhanced and directed evolution of the global transcriptional factor (IrrE) was applied to enhance cell viability in systems containing more substrate and ethanol, thus contributing to higher production.

Identification, Biological Characteristics, and Active Site Residues of 3-Ketosteroid Δ-Dehydrogenase Homologues from .

3-Ketosteroid Δ-dehydrogenase (KsdD) is the key enzyme responsible for Δ-dehydrogenation, which is one of the most valuable reactions for steroid catabolism. has been widely used in the industry due to its superior bioconversion efficiency, but KsdD information is not yet fully clear. Here, five KsdD homologues were identified in CGMCC 14539.

Compatible solutes adaptive alterations in Arthrobacter simplex during exposure to ethanol, and the effect of trehalose on the stress resistance and biotransformation performance.

Ethanol-tolerant Arthrobacter simplex is desirable since ethanol facilitates hydrophobic substrates dissolution on an industrial scale. Herein, alterations in compatible solutes were investigated under ethanol stress. The results showed that the amount of trehalose and glycerol increased while that of glutamate and proline decreased.

IrrE Improves Organic Solvent Tolerance and Δ-Dehydrogenation Productivity of Arthrobacter simplex.

During steroid bioconversion, organic solvents are widely used for facilitating hydrophobic substrate dissolution in industry. Thus, strains that tolerate organic solvents are highly desirable. IrrE, a global transcriptional factor, was introduced into Arthrobacter simplex with Δ-dehydrogenation ability.

1β,15α-Dihy-droxy-16α,17-ep-oxy-pregn-4-ene-3,20-dione.

The title mol-ecule, C21H28O5, is composed of three six-membered rings (A/B/C) and a five-membered ring (D). Ring A adopts a 1α-sofa conformation, while rings B and C adopt chair conformations. Cyclo-pentane ring D adopts a 14α-envelope conformation.

11α,15α-Dihy-droxy-androst-4-ene-3,17-dione.

The title compound, C(19)H(26)O(4), was biotransformed from androstenedione. In the crystal, inter-molecular O-H⋯O hydrogen bonds link molecules into a corrugated sheet, which lies parallel to the ab plane. Ring A has a slightly distorted half-chair conformation, rings B and C adopt chair conformations, while the cyclo-pentane ring D adopts a 14α-envelope conformation.

The influence of host-guest inclusion complex formation on the biotransformation of cortisone acetate Delta(1)-dehydrogenation.

An intensive and systematic investigation had been carried out on the Delta(1)-dehydrogenation of cortisone acetate (CA) to prednisone acetate (PA) by Arthrobacter simplex TCCC 11037 in the presence of native and modified beta-cyclodextrins (beta-CDs). The biotransformation was improved through the formation of the host-guest inclusion complex between CA and CDs in aqueous solution. The inclusion complexes of CDs with CA were investigated by means of phase solubility, 2D NMR spectroscopy and differential scanning calorimetry (DSC).