Recent trends and future prospects of solvent‐tolerant microbial platforms for green cholesterol biotransformation

Cholesterol is simultaneously an indispensable membrane component, a high-value feedstock for steroid pharmaceuticals, and an emerging aquatic contaminant. Green biocatalytic routes that convert cholesterol into pharmaceutically useful C19 intermediates (AD, ADD, 9-OH-AD, etc.) promise to replace harsh chemical syntheses, yet their industrial deployment remains sporadic. This mini-review (i) summarizes the physiological and environmental relevance of cholesterol; (ii) critically compares chemical and microbial transformation strategies; (iii) highlights breakthrough advances – including solvent-tolerant bacterial chassis, deep-eutectic/ionic-liquid media, enzyme immobilization, and AI-guided strain engineering; and (iv) identifies unresolved challenges such as low aqueous solubility, product recovery, and regulatory barriers. A roadmap for integrating data-centric solvent design with systems-biology-driven chassis optimization is proposed.