Optimization of cultivation strategies for production of recombinant human papillomavirus type 58 major capsid protein L1 in Hansenula polymorpha.

Abstract

Human papillomaviruses (HPVs) are a major cause of cervical cancer, which ranks fourth among cancers in women worldwide. A prophylactic vaccine composed of virus-like particles (VLPs) formed by the major capsid protein L1 of human papillomavirus (HPV) effectively prevents HPV infection but provides limited cross-protection against other HPV subtypes, highlighting the importance of multivalent prophylactic vaccines. In this study, cultivation conditions for recombinant HPV58 L1 protein production in the yeast Hansenula polymorpha were optimized to enhance growth and the volumetric yield of L1 protein. The results indicated that induction with methanol (at 1% v/v) was necessary for HPV58 L1 production in SYN6 medium, whereas a cultivation temperature of 37 °C was optimal for growth and production of HPV58 L1 protein. Subsequently, SYN6 medium supplemented with 10 g/L of either Hy-Express™ System II or HySoy was evaluated in batch and fed-batch bioreactor cultivations. Fed-batch cultivation with HySoy supplementation under a constant feeding rate achieved an OD₆₆₀ of 117 (26.18 g-CDW/L), a volumetric L1 yield of 312 mg/L, and a productivity of 4.7 mg/L/h, which were significantly higher than those obtained with the control SYN6 medium (92 mg/L; 2.2 mg/L/h). These findings demonstrate that fed-batch cultivation with HySoy supplementation offers a practical and efficient strategy for HPV58 L1 production at the bioreactor scale.