To realize a practical technology for recycling both cyclodextrin and resting-cells at the same time in phytosterol biotransformation using mycobacterial resting cells. In order to produce 22-hydroxy-23,24-bisnorchol-4-ene-3-one (HBC) efficiently and low-costly, a recycled phytosterols (PS) biotransformation process using mycobacterial resting cells was developed. By optimizing the ratio of hydroxypropyl-β-cyclodextrin (HP-β-CD) and PS to 1:1 (w/w), most products crystallized during the biotransformation process. So, the HBC was easily separated by low-speed (900×g) centrifugation with yield of 92%. The resting cells, HP-β-CD and the residual products and substrates left in the reaction system were reused for another bioconversion cycle after PS supplement. Three continuous cycles were achieved without the supplement of cells and HP-β-CD. In each batch, 80 g L−1 of PS was transformed to HBC with the space–time yield of HBC of 8.9–12.8 g L−1 day−1. This strategy reduced the cost of HBC production and simplified the purification process.

中文翻译：

---

分枝杆菌静息细胞从高浓度植物甾醇生产 22-hydroxy-23,24-bisnorchol-4-ene-3-one 的循环批量生物转化策略

利用分枝杆菌静息细胞进行植物甾醇生物转化，实现环糊精和静息细胞同时回收的实用技术。为了高效低成本地生产 22-hydroxy-23,24-bisnorchol-4-ene-3-one (HBC)，开发了一种使用分枝杆菌静息细胞的回收植物甾醇 (PS) 生物转化过程。通过将羟丙基-β-环糊精 (HP-β-CD) 和 PS 的比例优化为 1:1 (w/w)，大多数产品在生物转化过程中结晶。因此，HBC 很容易通过低速 (900 x g) 离心分离，产率为 92%。静息细胞、HP-β-CD 以及反应体系中残留的产物和底物在补充 PS 后重新用于另一个生物转化循环。在不补充细胞和 HP-β-CD 的情况下实现了三个连续循环。在每批中，80 g L-1 的 PS 转化为 HBC，HBC 的时空产量为 8.9-12.8 g L-1 day-1。这种策略降低了 HBC 生产的成本并简化了纯化过程。