A K. marxianus based Yeast Platform for Robust and High-yield Expression of Recombinant Proteins

K. marxianus is a thermotolerant fastest-growing eukaryote. The organism can assimilate a variety of sugars such as xylose, dextrose, fructose lactose and inulin. The unique properties of K. marxianus make it an attractive host for a number of industrial applications including large-scale protein production.

The group at CSIR-IMTECH has now constructed a K. marxianus strain with a number of auxotrophic markers. The expression vectors encoding novel constitutive and inducible promoters with novel terminators have been designed. The technology thus provides an alternative microbial host platform for protein or enzymes production.

Large-scale biologics and enzyme production require microbial host systems that are cost-effective, scalable, and capable of producing active, natively folded proteins. Kluyveromyces marxianus has emerged as an attractive non-conventional yeast due to its rapid growth, thermotolerance, and moderate glycosylation; however, its application has been limited by the lack of strong constitutive promoters, absence of inducible promoters, and availability of only a limited number of auxotrophic markers.

The group addressed these critical gaps by (i) engineering K. marxianus strains with multiple auxotrophic markers, (ii) identifying and developing novel constitutive and inducible promoters and (iii) identifying novel terminator sequences. The strength of the identified inducible promoter is tunable by varying the type of sugar present.

The outcome is a patentable, ready-to-use K. marxianus protein expression kit with the competent cells and expression plasmids.

• Engineered Host with Multiple Auxotrophic Markers – Enables efficient genetic manipulation and stable plasmid maintenance.
• Identified Next-Generation Strong Constitutive Promoters – Deliver protein yields far exceeding from existing
• Identified Novel Inducible Promoters – Provide rapid, reversible, and tightly controlled protein expression — a first-of-its-kind tool in marxianus.
• Industrial-Grade Physiology – Combines high-temperature tolerance, multi-carbon utilization, and rapid growth (~52 min doubling time) to cut production costs and enable scalable fermentation.
• Developed a commercial-ready-to-use expression kit with patent protection.