Molecular engineering of Komagataella phaffii for venom toxin production.

Animal venoms constitute a rich source of bioactive peptides and proteins with high target specificity, representing valuable scaffolds for therapeutic development. However, the biotechnological exploitation of venom-derived toxins is limited by challenges in achieving efficient, scalable, and reproducible production. Native venom extraction is constrained by low yields and biological variability, making recombinant platforms essential. Yet, most venom toxins are cysteine-rich peptides with complex disulfide bond architectures and stringent structure-function relationships, posing significant challenges to heterologous expression. Inefficient folding, proteolysis, and secretion bottlenecks frequently compromise functional yield. Among microbial hosts, Komagataella phaffii has emerged as a robust system combining eukaryotic protein processing with high cell-density fermentation and cost-effective cultivation. Its oxidative secretory pathway, strong and regulatable promoters, and suitability for strain engineering make it particularly attractive for producing disulfide-rich toxins. This review provides a critical analysis of recombinant venom toxin production in K. phaffii, focusing on molecular and bioprocess determinants of expression performance. We discuss post-translational modifications, yields, and bioactivity, as well as promoter selection and secretion signal optimization. By integrating data across toxin families, we identify recurring technical bottlenecks and highlight engineering approaches to enhance venom biomanufacturing within microbial biotechnology frameworks.